- Hops Plant Types: How Many Hops Varieties Are There
- Hops Plant Types
- A Brief Guide to Hops, and Hop Varieties
- Evaluating Hop Information for Brew Planning
- Hop Varieties – Alphabetically
- How are they used?
- The Complete List of All Hop Varieties on Earth
- Just How Many Hop Varieties Are There?
- What Are Hops?
- How Hops Affect Your Beer
- A Matter of Timing
- All Hop Varieties (Except the Secret Martian Ones)
- You’re Ready to Pursue Hoppiness
- Hop Varieties & Types: The Complete Guide to All the Different Flavor Profiles
- What Are Hops?
- The 3 Types of Hops (and How to Use Them While Brewing)
- The 3 Best & Most Popular Hop Profiles
- In conclusion…
- How Are Hops Used In Beer?
- Types of Hops
- Timing of Hop Additions
- Getting to Know Different Hop Varieties
- The Beer-Making Step You’re Probably Forgetting
- The Complete Guide on How to Grow, Harvest & Dry Hops at Home
- What is a Hop?
- 1. How to Grow Hops?
- 2. Harvesting
- 3. How to Dry Hops?
- 4. How to Store Hops?
- What Are You Waiting For? Hop To It
Hops Plant Types: How Many Hops Varieties Are There
Beer is officially made up of four ingredients: water, yeast, malted grain, and hops. Hops are the cone-shaped flowers of the female hops plant, and they are used to preserve the beer, clear it, help retain its head and, of course, gives it its classic bitter flavor. If you brew your own beer and you’re looking to get more involved in the process, growing your own hops is a great place to start. But how do you know which types of hops plants to grow? Keep reading to learn more about hops varieties and their uses.
Hops Plant Types
How many hops varieties are there? That’s a tough question to answer, because there are so many. There are about 80 different hops plant types commercially available today, but that number is not hard and fast.
Beer brewing is a complex business, and new varieties are constantly being bred and developed. Even 80 is an awfully high number if you’re looking to choose a single variety to grow. Luckily, there are some easy ways to narrow your selection down.
Hops can be split into three main categories: bittering, aroma, and dual.
- Bittering hops tend to have a high amount of acid in them and impart that recognizable bitter flavor onto the beer.
- Aroma hops have less acid but a more pronounced flavor and aroma, and are used to make the beer taste and smell a specific way. Most beer recipes call for both kinds of hops.
- Dual hops tend to have a mid-range to high amount of acid and a good smell and aroma, and can be used for both aroma and bittering. If you want to brew a beer with just your homegrown hops, one of these dual hops plant types is a good choice.
Best Types Of Hops Plants
The best hops varieties for doing double duty for both bittering and aroma have a nice strong scent and a mid-range to high Alpha Acid percentage (usually between 5% and 15%). If you’d like to be able to follow recipes when using your hops, it’s also a good idea to pick common hops plant types that are popular in recipes and well documented. A few good, popular, dual types of hops plants are Chinook, Centennial, and Cluster.
A Brief Guide to Hops, and Hop Varieties
Hops, that little green flower that you add to your beer. They are vital most beer styles. They add a bitterness that balances the sweet malty wort, flavors and aromas that range from spicy and piney to fruity and citrusy, and provide anti spoiling agents in their bitter oils to help keep beer from becoming infected. The longer hops are boiled, the more bitterness they add, but the less aroma and flavor they add. After 15 minutes, your aroma contributions will be almost none, and after 20 the flavor drops off. Between 21 and 44 minutes is kind of a dead zone where you aren’t getting great use from your bittering additions and not getting flavor or aroma either. 45-60 minutes is where you’ll get the most from your bittering hops.
Evaluating Hop Information for Brew Planning
When looking at a hop package in your local homebrew store, or browsing hops online, you may see a few words with percentages after them. These typically refer to Alpha Acids (AA), Beta Acids (BA), and Cohumulones. Alpha Acids contribute the bitterness to your beer through boiling. The higher the Alpha Acid content, the more bitterness you’ll get. So something with an AA of 4% like a noble hop, won’t add as much as a hop with 9% AA. Beta Acids are a bit more tricky. They don’t add any bitterness to your beer when boiled and only contribute a bitterness when beer becomes oxidized during long periods of aging or lagering. Cohumulones are a type of Alpha Acid, (the other relevant one being Humulones). Cohumulones add a harsher bitterness, while Humulones add a softer bitterness. These aren’t always listed on hop varieties so if you don’t see it, you can assume it’s an average amount. If it is particularly low or high it may be listed. Being familiar with how these acids work with your beer will help determine hops to use in recipe formulation along side their flavor and aroma profiles. Now let’s go over some popular hops in the homebrewing community.
Hop Varieties – Alphabetically
There are hundreds of hops varieties, and new ones pop up every year. Not all of them are available everywhere, or they sell out fast depending on popularity. Alpha Acids are listed in the middle of their typical range.
- Amarillo Pellets Admiral AA 14% Smooth Bitterness and faint citrus aroma
- Ahtanum AA 6% Citrusy and floral, strong grapefruit
- Amarillo AA 9% Citrus, Floral, Peach, Apple
- Apollo AA 18% Orange, strong bittering
- Azacca AA 15% Citrus, Tangerine, Grapefruit, Pine
- Admiral AA 14% Smooth Bitterness and faint citrus aroma
- Belma AA 12% Fruity, Melon, Clean
- Bramling Cross AA 8% Spicy, Lemon
- Bravo AA 15% Mild, Floral, Clean Bittering
- Brewer’s Gold AA 7% Earthy, Spicy, Black Currant
Delta AA 6% Mild spiciness, mild citrus
- East Kent Goldings AA 5% Smooth floral character
- Equinox AA 14% Floral, Apple, Herbal
- El Dorado AA 15% Cherry, Fruity, Pear
- Fuggles AA 5% Spicy
- Falconer’s Flight AA 10% Citrus, Floral, Grapefruit
- Falconer’s Flight 7Cs (or 7 Seas) AA 9.5% Fruity, Pine, Earthy
- First Gold AA 7% Spicy, Earthy
- Galena AA 12% Citrus
- Green Bullet AA 12% Fruity, Plum
- Glacier AA 5.5% Earthy, Floral, Citrus
- Galaxy AA 7% Tropical Citrus, Peach, Bright Fruitiness
- Hallertau AA 3% Spicy, Floral
- Herkules AA 14% Fruity, Spicy
- Horizon AA 12% Citrus, Floral, Clean Bittering
- Herald AA 10% Strong Bitterness, Grapefruit
- Hull Melon AA 7% Strawberry, Melon
- Kohatu AA 6% Strong floral, Pine, Citrus
- Legacy AA 7% Floral, Currants, Spicy
- Liberty AA 4% Mild Spice and Earthy
- Northdown AA 8% Clean, Woody
- Nelson Sauvin AA 12% Wine, Grapefruit,
- Northern Brewer AA 9% Neutral, Clean bitterness
- Nugget AA 12% Strong Herbal, Strong bitterness
- Opal AA 9% Spicy, Floral, Fruity
- Pacifica Pellets Progress AA 8% Mild Spice
- Pioneer AA 8% Mild Citrus
- Pride of Ringwood AA 9% Citrus, Herbal
- Phoenix AA 9% Clean Bitterness, Spicy
- Polaris AA 19% Mint
- Perle AA 7% Balanced Spice, Mild Bittering
- Pacific Jade AA 12% Peppery, Citrus
- Palisade AA 7% Fruity, Earthy
- Pacifica AA 5% Orange, Citrus, Floral
- Pacific Gem AA 14% Clean Bittering, Citrus, Summer Berries
- Rakau AA 9% Spicy, Stone Fruits
- Riwaka AA 6% Grapefruit, Citrus, Orange
- Super Alpha AA 11% Piney, Lemon
- Super Pride AA 9.5% Herbal
- Summit AA 18% Smooth, Orange, Citrus
- Stella AA 15% Spicy, Floral, Earthy
- Styrian Goldings AA 5% Spicy Aroma Hop, Mild
- Sterling AA 8% Floral, Mild Citrus
- Spalt AA 4% Spicy
- Sovereign AA 5% Earthy, Pine
- Sorachi Ace AA 13% Lemon
- Simcoe AA 14% Pine, Citrus, Smooth Bittering
- Saphir AA 4% Fruity, Citrus
- Saaz AA 4% Soft Bittering, Spicy
- Target AA 9% Herbal, Earthy
- Tettnang AA 4% Spicy, Woody
- Topaz AA 9% Spicy, Orange, Earthy
- Tradition AA 6% Floral, Earthy
- Ultra AA 5% Spicy, Floral
- Vanguard AA 5.5% Floral, Herbal,
- Warrior AA 16% Clean Bittering, Citrus
- Wakatu AA 8% Floral, Spice, Fruit
- Willamette AA 4.5% Herbal, Spicy
- Zythos AA 11% Strong Fruit, Citrus, Pine
How are they used?
Hops are a natural preservative and part of the early use of hops in beer was to preserve it. Hops were added directly to the cask after fermentation to keep it fresh while it was transported. This is how one particular style of beer, India Pale Ale, was developed. At the turn of the 18th century, British brewers began shipping strong ale with lots of hops added to the barrels to preserve it over the several month voyage to India. By journey’s end, the beer had acquired a depth of hop aroma and flavor. Perfect for quenching the thirst of British personnel in the tropics.
Beer wouldn’t be beer without hops – hops provide the balance, and are the signature in many styles. The bitterness contributed by hops balances the sweetness of the malt sugars and provides a refreshing finish. The main bittering agent is the alpha acid resin which is insoluble in water until isomerized by boiling. The longer the boil, the greater the percentage of isomerization and the more bitter the beer gets. However, the oils that contribute characteristic flavors and aromas are volatile and are lost to a large degree during the long boil. There are many varieties of hops, but they are usually divided into two general categories: Bittering and Aroma. Bittering hops are high in alpha acids, at about 10 percent by weight. Aroma hops are usually lower, around 5 percent and contribute a more desirable aroma and flavor to the beer. Several hop varieties are in-between and are used for both purposes. Bittering hops, also known as kettle hops, are added at the start of the boil and boiled for about an hour. Aroma hops are added towards the end of the boil and are typically boiled for 15 minutes or less. Aroma hops are also referred to as finishing hops. By adding different varieties of hops at different times during the boil, a more complex hop profile can be established that gives the beer a balance of hop bitterness, taste and aroma. Descriptions of the five main types of hop additions and their attributes follow.
First Wort Hopping
An old yet recently rediscovered process (at least among homebrewers), first wort hopping (FWH) consists of adding a large portion of the finishing hops to the boil kettle as the wort is received from the lauter tun. As the boil tun fills with wort (which may take a half hour or longer), the hops steep in the hot wort and release their volatile oils and resins. The aromatic oils are normally insoluble and tend to evaporate to a large degree during the boil. By letting the hops steep in the wort prior to the boil, the oils have more time to oxidize to more soluble compounds and a greater percentage are retained during the boil.
Only low alpha finishing hops should be used for FWH, and the amount should be no less than 30% of the total amount of hops used in the boil. This FWH addition therefore should be taken from the hops intended for finishing additions. Because more hops are in the wort longer during the boil, the total bitterness of the beer in increased but not by a substantial amount due to being low in alpha acid. In fact, one study among professional brewers determined that the use of FWH resulted in a more refined hop aroma, a more uniform bitterness (i.e. no harsh tones), and a more harmonious beer overall compared to an identical beer produced without FWH.
The primary use of hops is for bittering. Bittering hops additions are boiled for 45-90 minutes to isomerize the alpha acids; the most common interval being one hour. There is some improvement in the isomerization between 45 and 90 minutes (about 5%), but only a small improvement at longer times ( <1%). The aromatic oils of the hops used in the bittering addition(s) tend to boil away, leaving little hop flavor and no aroma. Because of this, high alpha varieties (which commonly have poor aroma characteristics) can be used to provide the bulk of the bitterness without hurting the taste of the beer. If you consider the cost of bittering a beer in terms of the amount of alpha acid per unit weight of hop used, it is more economical to use a half ounce of a high alpha hop rather than 1 or 2 ounces of a low alpha hop. You can save your more expensive (or scarce) aroma hops for flavoring and finishing.
By adding the hops midway through the boil, a compromise between isomerization of the alpha acids and evaporation of the aromatics is achieved yielding characteristic flavors. These flavoring hop additions are added 40-20 minutes before the end of the boil, with the most common time being 30 minutes. Any hop variety may be used. Usually the lower alpha varieties are chosen, although some high alpha varieties such as Columbus and Challenger have pleasant flavors and are commonly used. Often small amounts (1/4-1/2 oz) of several varieties will be combined at this stage to create a more complex character.
When hops are added during the final minutes of the boil, less of the aromatic oils are lost to evaporation and more hop aroma is retained. One or more varieties of hop may be used, in amounts varying from 1/4 – 4 oz, depending on the character desired. A total of 1-2 oz. is typical. Finishing hop additions are typically 15 minutes or less before the end of the boil, or are added “at knockout” (when the heat is turned off) and allowed to steep ten minutes before the wort is cooled. In some setups, a “hopback” is used – the hot wort is run through a small chamber full of fresh hops before the wort enters a heat exchanger or chiller.
A word of caution when adding hops at knockout or using a hopback – depending on several factors, e.g. amount, variety, freshness, etc., the beer may take on a grassy taste due to tannins and other compounds which are usually neutralized by the boil. If short boil times are not yielding the desired hop aroma or a grassy flavor is evident, then I would suggest using FWH or Dry Hopping.
Hops can also be added to the fermenter for increased hop aroma in the final beer. This is called “dry hopping” and is best done late in the fermentation cycle. If the hops are added to the fermenter while it is still actively bubbling, then a lot of the hop aroma will be carried away by the carbon dioxide. It is better to add the hops (usually about a half ounce per 5 gallons) after bubbling has slowed or stopped and the beer is going through the conditioning phase prior to bottling. The best way to utilize dry hopping is to put the hops in a secondary fermenter, after the beer has been racked away from the trub and can sit a couple of weeks before bottling, allowing the volatile oils to diffuse into the beer. Many homebrewers put the hops in a nylon mesh bag – a Hop Bag, to facilitate removing the hops before bottling. Dry hopping is appropriate for many pale ale and lager styles.
When you are dry hopping there is no reason to worry about adding unboiled hops to the fermenter. Infection from the hops just doesn’t happen.
Keeping pace with the beer hop scene can be as challenging as predicting the next culinary trend or Kanye West outburst.
There are scores of varieties, from the ever-popular Cascade to the lesser-known Lotus. Brewers work with the bitterness-imparting cones like a cook works with spices, dabbling here and there with different types, ratios, and, of course, results. These lovely nuggets do much more than just adjust bitterness units, they offer brightness and tons of unique flavors and fragrances.
With labs all over the country constantly researching and developing new beer hop types, we’d thought it would be a good idea to break down a few emerging styles.
The agricultural trend-setters at Oregon State University developed this hop, in tandem with Portland industry merchant Indie Hops. It’s gaining traction in the Willamette Valley and beyond, and for good reason, as it is layered and very aromatic. Those in the know have described its effects on beer as “cannabis meets passion fruit.”
Beer to try: The Strata IPA from Worthy Brewing out of Bend, Oregon. It shows nice tropical notes, alongside a grassy, subtly dank hit.
Pahto has been revered for its many uses as a hop that’s both bitter and clean. Developed in Yakima, this variety is a little earthy, a little floral, and nicely balanced. The name refers to the title indigenous people gave to nearby Mt. Adams.
Beer to try: Varietal Beer Company of Sunnyside, Washington touts the hop in its nicely-assembled Wapahto IPA.
The delightfully-named Cashmere hop is more on the delicate side, with a certain smoothness and light hit of citrus. It’s known to produce citrusy flavors, along with notes of melon and even coconut. Washington State University created this variety by crossing Cascade hops with Northern Brewer hops.
Anton Eine/EyeEm/Getty Images
Beer to try: Colorado’s Avery Brewing makes a fine whole-hopped IPA with an extra helping of Cashmere hops. While a limited release, expect to see more from this hop in the beers of of producers across the land.
Named after a Finnish agricultural god, Pekko delivers a nice balance of tropical fruit notes and herbaceous qualities. It also packs plenty of alpha acid content, meaning a bigger whack of bitterness by volume.
Beer to try: Short’s Brewing out of Michigan makes single-malt pale ale with a hop bill built solely around Pekko. It’s light and extremely approachable.
As the name suggests, Lemondrop hops are bright and zesty. They’re derived from popular Cascade hops and known to even impart green tea and spearmint notes. In addition to the obvious IPA category, keep your eyes peeled for this hop in newer takes on hefeweizens and blonde ales.
Pyramid Brewing Co./Facebook
Beer to try: Even the bigger guns are starting to work with this hop, including Seattle’s Pyramid. Their Lemondrop Citrus Pale Ale uses a dry version of the hop to create a refreshing, zippy beer perfect for the patio.
An offshoot of the Summit hop, Jarrylo shows ester-y qualities like banana and pear. With a bit of spiciness as well, it’s gaining a following among producers of Belgian-style beers. It was devised in the hop mecca otherwise known as Yakima Valley.
Beer to try: The Jarrylo by Ninkasi of Eugene is as easy-drinking as they come, and a fine example of what the hop can bring to the table.
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The Complete List of All Hop Varieties on Earth
Last Updated: March 19, 2019
Humans have an interesting relationship with leafy greens. Some, we use for decoration in our homes and gardens. Others, we toss in salad and smoothies, or use as garnish to help assuage our double-cheeseburger guilt. But the humble hop—while perfectly edible and pretty enough to complement the clematis in your backyard arbor—was destined for a greater purpose: beer.
The sheer number of hop varieties available can make choosing the right mix a daunting proposition. But once you understand how hops work, when they’re used, and what each type adds to your beer, a list of every single hop variety shifts from overwhelming to awesome.
Just How Many Hop Varieties Are There?
If you’re new to homebrewing, you may be wondering whether one ingredient warrants an entire list all its own. The answer is yes, because you’ll find roughly 147 hop varieties from around the world.
Before you start collecting, though, it’s important to understand what they are, what they do, and how to use them.
What Are Hops?
Grown on a bine—the technical term for a vine that lacks tendrils—the cone-shaped flowers of the plant called Humulus lupulus are packed with acids and oils that bring bitterness and aroma to finished beer. It’s a perennial, which means it comes back every year without having to replant it over and over. That’s a huge bonus in our book if you’re considering growing hops.
In addition to counteracting the natural sweetness of brewing malts, they’re also naturally antiseptic. This quality made the hop a blessing for early brewers looking to keep their beer healthy and tasty longer in a world before sterilization.
Hops can be added to your wort whole, either fresh or dried. You can also use dried hop pellets If you click this link and make a purchase, we earn a commission at no additional cost to you. . Depending on how many hops you add to your wort, and when you add them, you’ll achieve different results.
How Hops Affect Your Beer
Added before, during, or after the boil, hops will release into your wort the volatile compounds responsible for bitterness, flavor, and aroma.
The specific compounds of interest to you as a homebrewer are alpha acids, beta acids, and essential oils.
You can think of these chemicals as the Three Musketeers of beer bittering. The three most important alpha acids—Humulone, Cohumulone, and Adhumulone—are slowly transformed into what are known as iso-alpha acids as the wort boils, giving your beer a sharp, bitter taste.
This transformation process is called isomerization, and refers to the transformation of one type of molecule into another made up of the same components, but in a different bonding arrangement.
Alpha acids are also responsible for the antiseptic qualities of hops. In days of yore, beer makers had to rely on very high alcohol levels to make beer shelf-stable and safe. Adding hops not only killed off contaminating bacteria that caused illness and funky flavors, but also created a healthier environment in the wort for yeast to grow and ferment efficiently. Talk about a one-two punch!
Bitterness contributed by the alpha acids in hops is measured on the International Bitterness Unit (IBU) scale. One IBU is roughly equivalent to 1 milligram per liter (mg/l) or 1 part per million (ppm) of iso-alpha acids.
The scale runs from 1 to 100 IBUs. Bitterness ranges for common beer varieties include:
Wheat beers: 10–12 IBUs
American Pale Ale: 20–40 IBUs
Pilsner: 30–40 IBUs
IPA: 40 or more IBUs
For homebrewing, using an online IBU calculator makes bittering your beer a breeze. But if you’re itching to bust out your slide rule and pencil, you can also manually calculate IBUs:
IBU= (W(g) x U(%) x A(%) x 1000) V(l) x C(grav)
W is the weight of hops added, in grams.
U is hops utilization expressed as a percentage, taken from one of several available hops utilization tables.
A is the alpha acid percentage of the hops being used.
V is wort volume, in liters.
C is the gravity correction factor, which can be used to ensure accuracy for brews with a specific gravity, or density compared to water, higher than 1.050. If necessary, you can calculate C thusly:
C(grav) = 1+ ((G(b) -1.050)2)
Where G(b) is the specific gravity of your boiled wort.
Whichever method you use, it’s worth noting that IBU can only tell you how bitter your wort or beer will be, and not what kind of bitterness it will have.
Important: Despite their bittering and antibacterial superpowers, alpha acids can undergo another, less desirable chemical transformation if they’re exposed to light during fermentation. When iso-alpha acids combine with the riboflavin (Vitamin B12) in wort, exposing them to light will skunk your beer faster than you can say, “Yeesh, what’s that smell?” Keeping your wort in a dark place while it ferments and conditions, or using dark glass bottles If you click this link and make a purchase, we earn a commission at no additional cost to you. , will help you avoid the Pepe Le Pew effect.
Compared to alpha acids, most hops contribute relatively low levels of beta acids to beer. Beta acids form another trio of compounds: Lupulone, Colupulone, and Adlupulone. They have quite strong antiseptic properties. They also add a smaller amount of bitterness to the mix, but it’s much sharper.
This bitterness comes from a different source than the primary bittering produced by alpha acids. Beta acids oxidize, or react with oxygen, in beer over time. This can create subtle (or not-so-subtle) changes in the flavor of beer that’s stored for a long time, such as lagers.
Rich in both scent and taste, these oils are a flavorful but volatile component of the hopping process. Many boil off in just minutes, so in order to add the uniquely floral, spicy, earthy or citrusy flavors they bring, you can add more hops during fermentation.
Four compounds found in hops contribute a total of 60% to 80% of the total essential oils:
Humulene contributes strong, hoppy flavors when added late in the boil or during fermentation. It has the longest-lasting impact on both flavor and aroma.
Myrcene is especially prevalent in hops grown in the United States, and adds citrus and pine aromas and flavors to beer.
Caryophyllene is known for producing a “spicy” scent and flavor.
Farensene is the least present of the essential oils in most hop varieties, and doesn’t contribute much aroma or flavor to finished beer.
A Matter of Timing
Traditionally, you’d add hops to the wort during the first boil, before fermentation, to extract bittering compounds and harness the plant’s antiseptic qualities via isomerization. The process can take anywhere from 45 to 90 minutes, depending on the desired profile.
Because boiling destroys the essential oils and the delicate flavors they impart, adding hops in the final five to fifteen minutes of the boil, or alternatively, after the wort’s been boiled, can enhance aroma and flavor without adding significant bitterness.
You can also add dried hops (or hop extracts) late in the fermentation or conditioning phase using a process called dry hopping. By waiting until bubbling has stopped, you can prevent the flavorful essential oils from being carried away by carbon dioxide.
A variation called wet hopping uses fresh, rather than dried, hops to add aroma and flavor, but is otherwise identical to dry hopping. In addition to adding aromas and flavors, dry hopping can also increase beta acid levels in your finished beer, combatting spoilage while also increasing bitterness over time.
Another hopping process known as first wort hopping can reduce the risk of boil-over while potentially boosting the hoppy flavors in your finished beer. Rather than wait until fermentation, you add hops to the brew kettle If you click this link and make a purchase, we earn a commission at no additional cost to you. as the wort transfers from the lauter tun.
Sticking to hops with low concentrations of alpha acids If you click this link and make a purchase, we earn a commission at no additional cost to you. is best for first wort hopping. They’re in the kettle longer, so a lower concentration of acid keeps the additional bitterness they contribute at reasonable levels.
All Hop Varieties (Except the Secret Martian Ones)
Now that you’ve brushed up on your beer-based botany and hopping techniques, you can give your full attention to the master list of hop varieties, carefully collected from around the globe.
For brewing purposes, hops are readily broken into three categories: bittering, aromatics, and dual purpose. Like the notes of a delicate sonata or the application of spicy mustard to a well-grilled bratwurst, each has their part to play in creating your beer’s flavor and aroma.
After you’ve familiarized yourself with each category, get ready to dig deep. Check out the spreadsheet we’ve built containing not only all hop varieties (and their particulars), but yeast varieties, brewing malts, extracts, and adjuncts, too.
Flavor, schmavor. High in alpha acids and low in essential oils, these hops are bred to bring the bitter. European varieties are often higher in alpha acids than new world hops, and so are used to a greater extent for bittering. This isn’t a hard-and-fast rule, however, as Tomahawk
( also called Columbus If you click this link and make a purchase, we earn a commission at no additional cost to you. or Zeus), Nugget If you click this link and make a purchase, we earn a commission at no additional cost to you. , and Bravo If you click this link and make a purchase, we earn a commission at no additional cost to you. hops are excellent bittering hops produced in the United States.
Bittering hop varieties include:
- Brewers Gold
- Green Bullet
- Hallertauer Taurus
- HBC 682
- Magnum (Germany)
- Magnum (United States)
- Nugget (Germany)
- Nugget (United States)
- Pacific Gem
- Pacific Sunrise
- Southern Star
Higher in oils than their bittering kin, these hops introduce notes of grass, fruit, earth, honey, flowers, and spice to your beer. In general, hops from North America tend to be more aromatic than their European counterparts, although noble hops are an obvious exception.
- Brewers Gold
- East Kent Goldings
- Falconer’s Flight 7C’s®
- Falconer’s Flight®
- Golding (United Kingdom)
- Golding (United States)
- Hallertauer Mittelfrüh
- Hallertauer Tradition
- HBC 472
- Hersbrucker Pure
- Huell Melon
- Mandarina Bavaria
- Mount Hood
- Pacific Hallertau
- Saaz Triploid B
- Savinjski Golding
- Spalter Select
- Styrian Golding
- Tettnanger (Germany)
- Tettnanger (United States)
- Whitbread Golding
Dual Purpose Hops
Flexible and balanced, these hops can be used to add bitterness in the boil or added after for flavor and aromas. They come from a variety of sources around the world.
- Bitter Gold
- Bramling Cross
- Dr. Rudi
- First Gold
- Hallertau Aroma
- HBC 431
- HBC 438
- Hüller Bitterer
- Mount Rainier
- Nelson Sauvin
- Northern Brewer (Germany)
- Northern Brewer (United States)
- Pacific Jade
- Perle (Germany)
- Perle (United States)
- Pride of Ringwood
- Sorachi Ace
- Southern Brewer
- Southern Cross
- Southern Promise
- Super Alpha
- Super Pride
- Super Styrian (Aurora)
What About Noble Hops?
You don’t need a noble peerage or a suit of armor to appreciate these hops. The noble in noble hops refers to the venerated status of four of the oldest, and most traditional, hop varieties:
Saaz If you click this link and make a purchase, we earn a commission at no additional cost to you. , Tettnanger If you click this link and make a purchase, we earn a commission at no additional cost to you. , Spalt If you click this link and make a purchase, we earn a commission at no additional cost to you. , and Hallertau Mittelfrüh If you click this link and make a purchase, we earn a commission at no additional cost to you. . They tend to have more essential oils (particularly Humulene) than run-of-the-mill hops, and you’ll likely pay a bit more for these cherished heirloom varieties than you will others.
Like true Champagne, noble hops are valued for their origins, since the soil they grow in gifts each with a unique blend of spice, aroma, and finish. All four varieties are classified as aromatic hops, but Tettnanger’s subtle flavor gives it some leeway for use as an effective bittering hop as well.
You’re Ready to Pursue Hoppiness
The curtain has been peeled back, and the once-mysterious hop no longer holds any mysteries for you. Like a master chef, you’re ready to choose and use the perfect hops to tweak flavor, aroma, and finish.
Whether you want to sharpen the bite of your English bitter or whip up a fruity, lemony lambic, choosing the right hop varieties will help you achieve your beer making—and enjoying—goals.
Fundamentals of beer and hop chemistry
Denis De Keukeleire
University of Gent – Faculty of Pharmaceutical Sciences – Laboratory of Pharmacognosy and Phytochemistry – Harelbekestraat 72 B-9000 – Gent – Belgium
E-mail: [email protected]
Recebido em 8/12/98; aceito em 23/3/99
Beer brewing is an intricate process encompassing mixing and further elaboration of four essential raw materials, including barley malt, brewing water, hops and yeast. Particularly hops determine to a great extent typical beer qualities such as bitter taste, hoppy flavour, and foam stability. Conversely, hop-derived bitter acids account for an offending lightstruck flavour, which is formed on exposure of beer to light. These various processes are presented in detail, while due emphasis is placed on state-of-the-art hop technology, which provides brewers with efficient means to control bitterness, foam, and light-stability thereby allowing for the production of beers with consistent quality.
Keywords: beer; brewing; hops; bitter taste; flavour.
Beer is a fermented aqueous drink based on starch and flavoured by hops. This simple definition encompasses the four essential ingredients, which are necessarily used in the brewing of beer (Scheme 1). The body of the beer is provided by barley, more specifically barley malt, and, in general, a few hundreds of grams are used for one litre of beer. The malt may be partly substituted by starch-rich adjuncts, such as rice, corn or wheat. When a slurry of barley malt and brewing water (called ‘mash’) is heated at a temperature around 60°C, the malt enzymes, mainly amylases but also proteases, degrade starch and proteins, leading to a mixture of sugars and peptides or amino acids. For that purpose, barley must be subjected, prior to mashing, to a controlled germination, during which these enzymes are formed in the barley grain. Such germinated barley is known as barley malt. The starch-to-sugar conversion is stopped by heating. Depending on the conditions (time, temperature), pale or amber-coloured or even dark malts are obtained, the colour being due to caramelization of sugars and to Maillard-type reactions. It is important to notice that the colour of beer is derived from the colour of the malt(s) used. Furthermore, it is obvious that coloured malts exhibited a distinct taste, which often is characteristic of particular dark beers.
After filtration, the sugar solution, in brewers’ jargon called ‘wort’, is transferred to the brewing kettle, where it is boiled during at least one hour with the addition of hops (Humulus lupulus L.). The amount of hops needed is only a fraction of the substantial quantities of malt used in the brewery. Usually, a few grams of hops are sufficient as a quantitatively minor, but qualitatively major ingredient with crucial impact on well-defined beer features. Besides the formation of insoluble complexes with proteins and polypeptides, contributing to the colloidal stability of beer, hops sterilize the wort solution, which takes care of the bacteriological stability of beer. The most important asset of hops is the bitter taste conferred to, particularly, blond beers. Furthermore, hops are necessary for the stabilization of beer foam, while, on the other hand, the most precarious off-flavour in beer, called lightstruck flavour, involves degradation of hop-derived components (see below).
After cooling and removal of spent hops, the liquid, known as ‘hopped wort’ is pumped to the fermentation vessels and yeast is added under aeration for growth. During the anaerobic phase yeast cells convert sugars to ethanol and carbon dioxide. Depending on the temperature during fermentation and the nature of yeast collection at the end of the fermentation period, beers are distinguished as being produced by ‘bottom fermentation’ or ‘top fermentation’. Yeast strains, appropriate for bottom-fermented beers (Saccharomyces carlsbergensis), are active below 5°C and they settle to the bottom of the fermentor after production of about 5% ethanol. Conversely, yeasts, typical for the production of top-fermented beers (Saccharomyces cerevisiae), operate at ambient temperature and resist higher concentrations of ethanol, up to 12%. When the activity stops, the yeast cells collect to the top as a dense foam.
A typical fermentation takes about one week thereby delivering a so-called ‘green beer’ or ‘young beer’, which is not drinkable, as a number of offending (bad taste and smell) compounds are formed during fermentation. Consequently, beers need a maturation or lagering period of several weeks at about 0°C, during which the unwanted components are slowly decomposed. High concentrations of diacetyl and pentane-2,3-dione are particularly obnoxious for the quality of lager beers (‘pilsner-type’) and scrutinous monitoring is required. Only after the content has decreased below critical values (ppb-ranges), beer can be packaged. For prolonged conservation beers may be pasteurized. Special beers often require a slow (several months) second fermentation, usually in oak kegs, to generate sour flavours.
COMPLEX HOP FLAVOUR CHEMISTRY
The tastes of varying beer types are derived from a judicious choice of raw materials. Hops, in particular, account, in addition to the bitter taste, for a delicate hoppy flavour in beer. Until now, this extremely valuable organoleptic feature has not been fully defined. It is generally accepted that the hoppy aroma in beer is a complex of sensory impressions resulting from many different volatile compounds at low concentrations, many of them acting in synergism1. It appears that volatiles, contained in the hop oil (0.5-3% in hops), and non-volatiles, present in the hop polyphenolic fraction (3-6%), contribute to a full mouthfeel during beer tasting. However, the composition of these hop fractions is very complex and their study has been hampered by the low and varying concentrations normally found in beer. Thus, detailed insights are, at present, elusive.
Obviously, during the boiling of hops in wort many constituents are volatilized or oxidized and the hop-derived constituents, present in beer, are to a large extent different from the original molecules, present in hops. It should be interesting to trace the fate of individual volatile hop constituents, particularly terpenes, such as myrcene, caryophyllene, humulene and farnesene, during wort boiling, but the variability due to differing conditions and beers preclude that general statements be made. An inevitable conclusion is that the very intricate composition of the hop oils becomes even more complex during wort boiling.
Many brewers try to conserve part of the original composition by adding precious hop varieties (‘aroma hops’) near the end of the boiling period. This procedure, known as ‘late hopping’, may be combined with ‘dry hopping’, a special technique involving addition of hops to beer just before packaging. By doing so, some original hop constituents are directly transferred to the aqueous matrix thereby imparting a discrete hoppy character to the beer. The growing success of small brewers (microbreweries, brewpubs) suggests increasing recognition of the opportunities that the use of hops presents, in particular for developing various hop aromas and flavours.
Hops may contribute up to about one third of the total polyphenols in beer. Little doubt now remains that, amongst the polyphenolics, the low-molecular-weight proanthocyanidins determine the colloidal stability of beer. The net result of boiling is a dramatic change in the already complex polyphenol composition of wort2. It seems to be impossible to get a reasonable insight into the fate of the polyphenolic mixture. Part of the complexity can undoubtedly be ascribed to the ready oxidation and the ease of polymerization of many polyphenols.
Hop polyphenols are found as monomers, dimers, trimers, but also as more complex forms associated with nitrogenous components. It is common practice to distinguish between ‘chill haze’ and ‘permanent haze’. The polyphenols combine slowly with proteins to form chill haze when cooled, but which redissolves when warmed up. As the polyphenols polymerize and grow larger, they become insoluble at room temperature to form irreversible haze. The extent to which a beer requires stabilization depends on its shelf-life and the storage conditions after packaging. It appears that hop polyphenols are a group of substances with interesting effects on taste and taste stability of beers. Taking, moreover, the pronounced ‘natural’ anti-oxidant character of particular polyphenols into account, it is obvious that, in the future, more attention will be focussed on the various roles of polyphenols in brewing.
THE CHEMISTRY OF THE BITTER BEER TASTE
Bitter profiles in beer are well understood, as only few precursors are present in hops, thereby facilitating research of beer bitter components3,4. Perhaps the most important class of hop compounds are the hop acids, which are distinguished as alpha-acids or humulones (1) and beta-acids or lupulones (2) (Scheme 2). The two series comprise, in fact, three constituents differing in the nature of the side chain, which is derived from the hydrophobic amino acids, leucine, valine and isoleucine, for humulone (1a)/lupulone (2a), cohumulone (1b)/colupulone (2b) and adhumulone (1c)/adlupulone (2c), respectively. An intriguing feature of the hop acids is their exceptionally high content, up to 25% or even more, of the dry weight of the hop cones. The relative proportions of the individual constituents depend strongly on the hop variety and, for a given variety, on the conditions of growing. The hop acids occur as pale-yellowish solids in the pure state, are weak acids, exhibit very poor solubility in water and have almost no bitter taste.
The hop acids have pronounced bacteriostatic activity; they strongly inhibit the growth of Gram-positive bacteria. This action has been attributed to the interference of the prenyl group, characteristic of the side chains of the hop acids, with the function of the cell plasma membrane. It appears that the more prenyl groups (three in the beta-acids) are present, the stronger the bacteriostatic action is. This remarkable bio-activity is of importance for killing micro-organisms during wort boiling, which ultimately leads to a sterile beer.
Varying applications have been explored to exploit the bacteriostatic activity of the beta-acids. A highly interesting use is in the sugar industry to control and reduce bacterial activity during extraction of sugar beets5. By dosing the hop beta-acids periodically in amounts of 10 g per ton of beet, the lactic acid content of raw juice was reduced to 400 ppm without influence on the fermentation. Investigations on the fate of the hop compounds showed that residual values in sugar, molasses and pulp are undetectable or uncritical. It appears that formalin, a widespread processing aid in the sugar industry, could be advantageously replaced by hop beta-acids.
Otherwise, the beta-acids are very sensitive to oxidative decomposition and most oxidation reaction products possess unpleasant organoleptic characteristics. Notwithstanding the fact that the beta-acids may possibly protect beer against oxidation, they are, in general, considered a negative factor in brewing and a number of brewers select hop varieties, that are poor in beta-acids.
The major component of the mixture of alpha-acids is humulone (1a). While the relative amounts of humulone (1a) and cohumulone (1b) are variety-dependent (20-50%), adhumulone (1c) constitutes invariably ca. 15% of the mixture. Cohumulone has been associated with a poor hop quality, although this issue is not proven unambiguously6. Detailed analysis by HPLC (high performance liquid chromatography) – MS (mass spectroscopy) reveals the presence of other related alpha-acids, albeit in very small concentrations.
The transformations of the humulones during wort boiling have been studied in great detail3. By far the most important chemical conversion overall during the brewing of beer is the thermal isomerization of the alpha-acids or humulones (1) to the iso-alpha-acids or isohumulones (3 + 4) via an acyloin-type ring contraction (Scheme 3). Each humulone gives rise to two epimeric isohumulones, which are distinguished as cis-isohumulones (3) and trans-isohumulones (4), depending on the spatial arrangement of the tertiary alcohol function at C(4) and the prenyl side chain at C(5). The terms trans and cis indicate that these groups point to opposite faces and to the same face of the five-membered ring, respectively.
Thus, humulone (1a) is isomerized to cis-isohumulone (3a) and trans-isohumulone (4a). Consequently, six major iso-alpha-acids (cis-isohumulone and trans-isohumulone, cis-isocohumulone and trans-isocohumulone, cis-isoadhumulone and trans-isoadhumulone) are present in beer resulting from the conversion of the three major alpha-acids, humulone, cohumulone and adhumulone, respectively. Figure 1 represents a reversed-phase HPLC separation of the six major isohumulones in a typical lager beer. The early part of the chromatogram refers to an oxidized fraction and is representative of the ‘freshness’ of the iso-alpha-acids.
The ratio of the isohumulones depends on the reaction conditions. In the wort medium it is normally 68:32 in favour of the cis-compounds. However, the cis-compounds are much more stable (half-life >> 5 years) than the trans-isomers (half-life of ca. 1 year) during the course of time. This affects, obviously, the cis:trans ratio and has significant consequences with respect to taste and flavour stability. Thus, it appears interesting to have the highest content of cis-isohumulones possible in the mixture of isohumulones.
The iso-alpha-acids are intensely bitter, almost equivalent to quinine, the reference compound for comparisons of bitterness. The threshold value in water has been estimated at 6 ppm. The iso-alpha-acids constitute the quantitatively most important fraction of hops in beer and they account for the typical bitter beer taste. Their concentrations vary widely, from 15 ppm in typical American lager beers to nearly 100 ppm in very bitter English ales. The real taste, as perceived by beer consumers, is largely modified by complexation with residual sugars, present in beers, and, thus, the bitterness is evaluated as ‘pleasant bitterness’.
There are conflicting views on the bittering power of the individual isohumulones, mainly as a consequence of differences in purity of the compounds that have been used in taste trials. Purification of iso-alpha-acids is particularly difficult and reported results should be interpreted with great caution. The utilization of cohumulone (1b) is better than that of the other alpha-acids due to the more polar character and the increased solubility in water. The organoleptic features of the isocohumulones, however, are subject to some suspicion, as they generate a more ‘harsh’ bitterness with respect to the other isohumulones.
In addition to imparting bitter taste to beer, the iso-alpha-acids exhibit other interesting features: they have tensioactive properties, thereby stabilizing the beer foam, and inhibit the growth of Gram-positive bacteria, thus protecting beer against these micro-organisms. On the other hand, lactic acid bacteria in beer are resistant to iso-alpha-acids.
THE LIGHTSTRUCK FLAVOUR OF BEER
It has been thought that iso-alpha-acids and phenolic compounds are key components with regard to beer stability. Iso-alpha-acids are partly responsible for production of ageing off-flavours, including stale and cardboard flavours7. Volatile aldehydes, such as trans-non-2-enal, are formed during storage of bottled beer from various precursors, including hop lipids. On the other hand, it has been known for quite some time that beer decomposes on exposure to light, thereby generating an offending ‘skunky’ flavour. Thus, beer must be stored, either in opaque cans, or in green or brown bottles, in order to prevent light from being transmitted through the glass.
The cause for this phenomenon is the vulnerability of the iso-alpha-acids to light. The resulting decomposition leads to formation of the so-called ‘lightstruck flavour’. The light-sensitive chromophore in the isohumulones is the acyloin group composed of the tertiary alcohol function at C(4) and the carbonyl group of the side chain at C(4). Activation of, for example, the isohumulones 3a and 4a with UV light causes bond cleavage by a Norrish Type I reaction, leading to a ketyl-acyl radical pair. Subsequent loss of carbon monoxide from the acyl radical and recombination of the resulting fragment with a thiol radical furnish 3-methylbut-2-ene-1-thiol, also known as ‘skunky thiol’ (5, Scheme 4), together with dehydrohumulinic acid (6a)8.
The mechanism for the formation of the lightstruck flavour was confirmed by the unambiguous identification of 3-methylbut-2-ene-1-thiol in illuminated beers. The flavour threshold of the thiol is so low that even concentrations of few ppb spoil irreversibly the beer quality. The thiol is formed also on exposure to visible light or sunlight. Since the iso-alpha-acids do not absorb in the visible region, the reaction is photosensitized, in first instance by riboflavin (vitamin B2)9.
NOVEL HOP TECHNOLOGY TO CONTROL BITTERNESS, FOAM AND LIGHT-STABILITY OF BEERS
The isomerization of alpha-acids to iso-alpha-acids during wort boiling suffers from low yields, which are seldom higher than 30%. The transfer of the alpha-acids from the vegetative hop material, the restricted solubility of the alpha-acids in the aqueous matrix and the almost neutral wort (pH 5-5.5) are critical factors. A better utilization of hops is effected when hop extracts are used (40-50%). Liquid or supercritical carbon dioxide is, indeed, an excellent medium to extract both the hop acids and the hop oil from hops. Thus, new technologies aimed at exploiting the full potential of hops and optimizing the utilization of hops in the brewing of beer – on the basis of original findings in our laboratory – are gaining considerable importance. Opportunities for the development of more flavour-consistent beers and diversified beer types abound.
Hops are fractionated on an industrial scale to a variety of ‘hop products’, based on liquid or supercritical carbon dioxide extracts4. While the polyphenols reside in the spent hops, an extract, rich in hop acids, or an extract, rich in hop oil, may be obtained, depending on the operating temperatures and pressures. The hop volatiles can be separated from the oil-rich extract as ‘hop essences’. Crude fractionation of the total hop oil provides a ‘floral oil’ and a ‘spicy oil’, respectively. The hop alpha-acids are accessible from a hop-acids-rich extract using selective, pH-controlled solvent extraction. The alpha-acids prevail then as a concentrate, which can readily be isomerized to the iso-alpha-acids, the principal beer bitter constituents. Isomerization may be carried out by heating solid salts of particular metal ions, e.g. magnesium(II) humulates. Alternatively, irradiation of the alpha-acids in the wavelength region of 350-366 nm (UV-A light) provokes a fully regio- and stereoselective photorearrangement, thereby affording exclusively trans-isohumulones (4)8. Yields are in both cases almost quantitative.
These isohumulones, thus produced off-line (i.e. not by brewers, but by hop processors), are formulated as potassium salts in concentrated aqueous solution. Such advanced hop products can be applied to add bitterness to beer or to adjust bitterness levels at any stage during the brewing process. Best organoleptic results are obtained when the isohumulones are added near the end of wort boiling, hence when they fully participate in fermentation and lagering. It was found that introduction of isohumulones just before packaging must be accompanied by addition of very small amounts of hop oil (ca. 1 ppm) in order to make such ‘advanced’ beers indistinguishable from ‘traditional’ beers10. Yields of isohumulones, thus applied, exceed 80%.
Further manipulation of the iso-alpha-acids is carried out with the principal aim to brew foam- and light-stable beers. In practice, iso-alpha-acids are converted to reduced iso-alpha-acids with quite interesting properties11. Three major types of reduced iso-alpha-acids should be considered depending on the number of hydrogen atoms (dihydro, tetrahydro, hexahydro) incorporated during reduction.
Sodium borohydride reduction of the carbonyl group in the side chain at C(4) of the isohumulones gives rise to dihydro-isohumulones (also known as ‘rho-isohumulones’), which are perfectly light-stable, as the light-sensitive acyloin group has been converted to a diol. Since formation of the secondary alcohol function is accompanied by creation of a new chiral centre, two epimeric dihydro-iso-alpha-acids arise from each iso-alpha-acid, e.g. compounds 7a and 8a from trans-isohumulone (4a) (Scheme 5). Consequently, a mixture of twelve dihydro-iso-alpha-acids may result from reduction of the six major iso-alpha-acids. However, dihydro-iso-alpha-acids products are usually less complex due to the reaction conditions employed and the resulting selectivities. Substitution of iso-alpha-acids by dihydro-iso-alpha-acids allows brewing of light-stable beers, which can be bottled in clear glass.
Tetrahydro-iso-alpha-acids are obtained by hydrogenation of the double bonds in the side chains of the iso-alpha-acids, e. g. trans-tetrahydro-isohumulone (9a) from trans-isohumulone (4a). Commercially available tetrahydro-iso-alpha-acids are produced as a mixture of six tetrahydro-iso-alpha-acids. Via reversed phase HPLC analysis of a beer, made from iso-alpha-acids, in conjunction with tetrahydro-iso-alpha-acids, the composition of the bitter constituents can be revealed, as shown in Figure 2. Saturation of the double bonds leads to diminished reactivity and enhanced hydrophobicity, which has a pronounced foam-positive effect. Since the acyloin group is still present, photochemical reactions may occur on light exposure, although the allyl radical, intervening in the formation of 3-methylbut-2-ene-1-thiol (5), can no longer be formed. Hop products, based on tetrahydro-iso-alpha-acids, have become very popular recently, particularly in view of the pronounced propensity to stabilize beer foam (Scheme 6). Brewers take advantage of this by adding few ppm of tetrahydro-iso-alpha-acids to create a creamy head on a glass of beer.
Hexahydro-iso-alpha-acids are accessible by a combination of the aforementioned processes, i.e. reduction of the side-chain carbonyl group and hydrogenation of the double bonds in the iso-alpha-acids. Trans-isohumulone (4a) would afford trans-hexahydro-isohumulones 10a and 11a, while the mixture of hexahydro-iso-alpha-acids could theoretically be composed of twelve isomers and homologues. Real samples of hop products based on hexahydro-isohumulones are much simpler as observed on HPLC separation.
Beer is an extremely complex drink and several hundreds of constituents have been identified hitherto. Hops are vital to the organoleptic qualities of beer, including taste and flavour. During the multi-stage brewing process many hop components are modified, but even the use of sophisticated separation and analysis techniques has, until now, not allowed to identify unambiguous relations between particular hop-derived compounds and sensory characteristics.
As opposed to the intricate chemistry of hop oils and hop polyphenols, the bitter taste features of beer have been adequately profiled. Alpha-acids or humulones are converted during wort boiling to iso-alpha-acids or isohumulones, which impart the typical bitter taste to beer. Modern hop technology has unlocked the full potential of hops by providing novel hop products, which allow brewers to adjust desired beer properties. Moreover, off-flavours, such as the lightstruck flavour, can be obviated by bittering beers with advanced hop products, based on reduced iso-alpha-acids or reduced isohumulones, thereby rendering beers light-stable.
Both bottom- and top-fermented beers, using advanced hop products, have been made in our pilot brewing facilities and sensory analysis proved their superior quality with respect to more traditional brews. Judicious application of advanced analytical methods has been essential to the successful penetration of new hop technologies into the beer world. State-of-the-art analyses involving high-efficient chromatographic variants (e.g. reversed phase HPLC)12 and electro-driven separation methods (e.g. CZE)13 have superseded classical unspecific protocols. Validated quantification of various hop-derived compounds must support beer quality control from a modern brewing perspective.
6. Meilgaard, M.; J. Inst. Brew. 1960, 66, 35.
8. De Keukeleire, D.; Blondeel, G. M. A.; Tetrahedron Lett. 1979, 1343.
9. De Keukeleire, D.; Heyerick A.; University of Gent, unpublished results, 1998.
10. De Cooman, L.; Overmeire, H.; Aerts, G.; De Keukeleire, D.; University of Gent, 1998, unpublished results.
12. De Cooman, L.; Everaert, E.; De Keukeleire, D.; Phytochem. Anal. 1998, 8, 1.
13. De Keukeleire, D.; David, F.; Haghebaert, K.; Sandra, P.; J. Inst. Brew. 1998, 104, 75.
Hop Varieties & Types: The Complete Guide to All the Different Flavor Profiles
New to brewing and want to know all about the different types of hops? You’ve found the right guide.
The 52Brews Guide to Hop Varieties will cover everything you need to know to get started down the zesty, citric, bittersweet road to brewing better beer.
In it, we cover:
- Hop Varieties and Their Flavors
- The Different Categories of Hops and How to Use Them in Brewing
- The Most Popular Types of Hops
Behold, the hop plant.
There are as many types of hops as there are reasons to love them (as in, lots). Good thing homebrewing fanatics have already done all the research for you!
What Are Hops?
Let’s start with the definition of a “hop.”
They’re the flower of the hop plant, also known to very smart people as humulus lupulus.
They are the bringers of balance in the beer world. Without them, your beer would be dull, sweet, and flavorless.
Just like chefs add herbs and spices to their creations to entice the palettes of diners, so do brewers for beer drinkers.
Hops are added to beer during the brewing process for several reasons:
- To add that essential bitter taste (beer would be sugary and sweet without them)
- To add those irresistible flavors we all love so much
- To act as a preservative
- To retain the head of the beer
“Hops are most often associated with bitterness, but that isn’t the only reason to use them.”
– Vine Pair
Before hops, people used just about anything they could to flavor their beer. Imagine using twigs and berries to flavor your beer (seriously, people did that).
Lucky for all of us, you can go get delicious, zesty, aromatic hops easier than ever before.
Before we get to the most popular hops for your beer, it’s important to understand the different categories of hops and their role in the brewing process.
The 3 Types of Hops (and How to Use Them While Brewing)
If you’re familiar with brewing, you know the term wort. It’s the sweet liquid byproduct of the mashing process (when grains steep in water to create fermentable starches).
Hope that’s all making sense.
Wort must then be boiled before it becomes your favorite bottled beverage.
During the boiling process, different varieties of hops are added according to their flavor profile and level of alpha acids.
New Term: Alpha acids: Alpha acids are responsible for the bitterness of beer and are found in hops. The higher the alpha acid measurement, measured as International Bitterness Units (IBUs), the more bitter the beer.
The 3 categories are:
- Bittering Hops: Also known as kettle hops, bittering hops are added at the start of the boil and are boiled typically for about an hour. Since these hops have a high acid range, they are more bitter. They are boiled longer so the heat can break down the acids and the wort can absorb them (a process known as isomerization).
- Aroma Hops: Also known as finishing hops, aroma hops are added for their flavoring. Since they boil for far less time, more of their flavor and character are captured by the beer.
- Dual-Purpose Hops: These hops are stuck somewhere in the middle. They can’t decide for themselves whether or not they work better as a bittering hop or an aroma. That’s up to you to decide (we clue you in on what the industry thinks below).
The 3 Best & Most Popular Hop Profiles
Now, it’s time for the fun part.
We’ve covered the most popular and delicious hop varieties and their flavor profiles in this article.
This is for you to get a good idea of what to expect, as well as their unique characteristics.
We’ll also include the types of beer they are normally used in.
Why go through the work of experimenting when big brewers have done it for you already? So…
1. Bittering Hops
Complete with pleasant fruit aromas and zesty hints of flowers, oranges, and vanilla, Bravo is a “super-bitter” variety of hops that is popular with pale ales.
The candied orange and delicate fruit notes mixed with its excellent bittering properties makes it one of the most popular varieties out there.
Another high alpha hop with balanced bitterness, Admiral’s aroma profiles are said to be anywhere from citrus to woody.
It isn’t as harsh or bitter as some others in this range either. Its resinous hop aroma also contains hints of herbal flavors.
Bred in Germany, Magnum is primarily a bittering hop variety used only for its extreme (but useful) bittering abilities.
The taste spectrum runs anywhere from pepper and nutmeg to a slight citrus tint. Its alpha % range makes it versatile enough to be included in multiple different types of beer.
2. Aroma Hops
2.1 Fuggle Hops
Earthy, woody, and full-bodied, Fuggle is one of the most revered flavoring hops in the world. Its earthy tones make it perfect for English style ales, bitters, and porters.
If you’re going for pleasant flavors with a floral hint, you can’t go wrong.
The most popular hop in American craft brewing, Cascade is a hop variety that has unique and powerful floral tones to go along with a spicy and exquisite citrus character.
This aroma palette is well balanced by its bittering potential. Its medium intensity makes it one of the most recognizable tastes in the industry. It’s perfect for IPAs and American Ales.
2.3 Hallertauer Classic
The classic German hops variety (not to be confused with the American imitation) is the aroma hop associated with german style lagers, bocks, and weissbier.
This hop’s tale is one of a clash of two extreme opposites: bright fruit underpinnings and harmonic bitterness. Spicy, herbal, and fruity, these hops are as a versatile as they are delicious.
3. Dual-Purpose Hops
3.1 Centennial Hops
Very similar to Cascade hops, Centennial dual-purpose hops are characterized by pine and citrus notes as well as a distinct hint of citrus.
The mix of delicate and aggressive aromas makes the perfect scent to please the olfactory glands of craft snobs from Portland to Brooklyn, but its powerful bittering qualities let it stand up to a wide range of malt.
Your options are limitless. The choice is yours.
Despite its high alpha profile, this versatile hop variety is dual purpose and dang good at what it does.
The hint of grapefruit is balanced out by the taste of spices and pine, creating a beautiful harmony that brewers love.
Dry hopping with Chinook is becoming more popular as of late and can even result in smoky flavors.
Hops may have changed a lot in the last few hundred years, but they’re crucial to the brewing process if you want nuanced, delicious brews.
Even as a budding brewer, your choice of hop varieties has never been wider. It’s up to you to find that perfect mix.
Did we leave any varieties out that you wanted to see? Which other flavors did you discover in your types of hops that we should know about?
Let us know so we can make our next hops guide even better.
Also, if you want a new DIY project, how about learning how to grow hops for the first time?
LEARN HOW TO GROW, HARVEST & DRY HOPS
Photo credit: Kate Ter Haar /Flickr/CC BY 2.0
Hops are the green, cone-shaped flowers of the female hop plant, also known by its scientific name Humulus lupulus. (Have fun with that one after a few beers.) Hops are chock full of alpha acids, which are the primary bittering agent brewers use to balance the sweetness in the beer imparted by grain during the brewing process. Hops are also a concentrated source of the essential oils that lend many beers their signature, intoxicating flavors and aromas. And before modern refrigeration, hops served as an important beer preservative.
How Are Hops Used In Beer?
Brewers use hops in beer to varying degrees. In some styles, like the omnipresent IPA, hops take centerstage. In other styles, like stouts, hops typically play a less obvious role; they add backbone and depth, but the beer’s flavor and aroma is mostly defined by the grain bill.
Coaxing particular characteristics out of hops takes skill and experience. Brewers manipulate which varieties of hops they use and for how long they’re boiled to achieve particular effects.
Hops come whole or in plugs and pellets, like these. Photo credit: Epic Beer/Flickr/CC BY 2.0
Types of Hops
Just as there are dozens of varietals of grapes used for winemaking, there are a ton of different kinds of hops available to brewers. And just like wine grapes, hops of different strains and from different growing regions bring to the table (or should I say kettle?) different flavors, aromas, and bittering capabilities.
For starters, hop strains differ in terms of their alpha acid and essential oil levels. Hops with high amounts of alpha acids are especially useful for adding sharp, angular bitterness to a finished beer. Hops with loads of essential oils contribute the most in terms of flavor and aroma. Some strains have sufficient levels of both to be appropriate for all three applications.
In general, hops strains are categorized by their geography of origin. The three most prominent categories are Noble hops, which come from Germany and the Czech Republic; American hops from the United States; and English hops, from–your guessed it–England. Within each category, there are many hop strains to choose from.
Of the three categories, Noble hops, which includes strains like Saaz and Tettnanger, are considered the most classic. They are what lend traditional German and Czech pilsners and lagers their characteristic flavor profiles. Noble hops tend to be particularly rich in the high-aroma essential oil humulene and have low alpha acid levels.
American hops, including heavy hitters like Cascade and Centennial, tend to be bold, bright, and highly aromatic. In general, they have higher amounts of the essential oil myrcene, which gives them their characteristic citrus and pine notes.
In contrast, English hops (Fuggle is an example) have lower levels of myrcene. This allows the more subtle aromas of other essential oils to shine through. The profiles of English hops, therefore, tend to be more delicate and mild. Notes of earth, molasses, herbs, spice, and wood are common. English hops constitute only a small percentage of hops grown worldwide but are imperative to traditional British ales.
Photo credit: Daniel Lobo/Flickr/CC0 1.0
Timing of Hop Additions
Brewers introduce hops to the beer making process after mashing. During mashing, grains steep in hot water to activate the malt enzymes and convert its starches into fermentable sugars. The sweet liquid byproduct is called wort, which must be boiled before it is fermented and turned into beer. During the boil, brewers add hops to the wort in stages to effect bitterness, flavor, and aroma.
Bittering hops are added to the wort toward the beginning of the boil and are left to bubble and steep for at least 45 minutes and up to an hour and a half. The heat catalyzes a chemical reaction called isomerization, which turns alpha acids into water soluble iso-alpha acids. The longer bittering hops are left to boil, the more iso-alpha acids are transferred to the wort.
At the same time, a long boil destroys the flavorful essential oils inherent to hops. If a brewer is using hops for flavor and wants to preserve those delicate compounds, he or she will add them later and boil them for a shorter duration–generally about 15 minutes but no more than about 30.
The essential oils in hops responsible for aroma are even more susceptible to the damaging effects of heat. For that reason, aromatizing hops are added at the very end and boiled for the shortest amount of time–typically not longer than five minutes.
Sometimes, aromatizing hops aren’t boiled at all. Instead, brewers may choose to steep them off the heat after fermentation, extracting the volatile oils slowly and gently over a period of days or even weeks. This method is called dry hopping, and it is commonly used in the production of Pale Ales and IPAs.
Getting to Know Different Hop Varieties
If you want to familiarize yourself with the different hop varieties available, you can order small quantities of hops online and spend time analyzing their aromatic profiles. More immediately, you should start reading the labels of the beer you drink. Breweries will often identify the hops used in a particular recipe on the bottle or can.
If a recipe uses multiple kinds of hops, it might be difficult to differentiate them at first. To educate your palate, try seeking out beers that showcase a single hop variety. Bell’s Brewery makes Two Hearted Ale with 100% Centennial hops, and it is widely available. Other single-hop beers include:
Liberty Ale | Anchor Brewing
Sorachi Ace | Brooklyn Brewery
Hops: Sorachi Ace
Zombie Dust | 3 Floyds Brewing Co.
Pilsner Urquell | Plzeňský Prazdroj
The Beer-Making Step You’re Probably Forgetting
When you’re tasting wine at a vineyard, you don’t have to look far to find the source of what’s in your glass. But when you’re downing pints at a craft brewery, have you ever thought about where that beer really came from?
You can likely take a tour and see the mash tuns churning away in the background, but there’s something else you’re missing: the actual growing of hops, one of beer’s basic ingredients. Even if you don’t think you like classically hop-forward IPAs, the bitterness they’re known for helps counter sweetness from another one of beer’s characteristic ingredients, malted barley, in a variety of beer styles.
Ed Atkins, head farmer at Elk Mountain Farms in Idaho, says one of the biggest misconceptions people have about hops is that they’re synonymous with bitterness. While they do contribute to flavor, that’s only a quarter of the story: They also attribute aroma, stabilize foam and act as a preservative, thanks to antimicrobial properties.
We got to see hops in action at a recent trip to Goose Island’s fields at Elk Mountain Farms, the largest contiguous hop farm in the world. There’s an ironic contrast between the peaceful, idyllic farm—merely 10 miles south of Canada—and the rowdiness that its final product inevitably leads to.
Atkins grows more than 60 types of hops across 1,700 acres and has truly revitalized the farm over the past couple of decades. Needless to say, he knows his crop well.
When hops grow, they look like a cross between apple trees and vines. Mesmerizing, seemingly endless vines span across the fields, dotted with individual hops that grow on the vines and look like miniature artichokes. Brewers are after the yellow powder inside called lupulin, which contains the hop acids and oils. If you ever get your hands on some fresh hops, split one in half and rub it on your skin—you’ll smell like you’ve started using IPA perfume.
In the same way that there are noble grapes used in winemaking (Cabernet Sauvignon, Riesling, Merlot), there are also noble hops. For example, Centennial and Cascade are pronounced in IPAs like Goose Island’s Goose IPA—which is the beer most produced from hops at Elk Mountain farms—while Saaz is prominent in great pilsners, especially from the Czech Republic. And hops too have terroir—that buzzy word sommeliers always throw around.
After being picked, the hops go through a maze of different sorting machines, plus heating and cooling, before being packed into hay bale-like bundles. It takes 200 pounds of hops to produce a single pallet, as after the moisture is released, the leaves are significantly lighter, almost feather-like. This signals the end of the hops’ time on the farm, but they still have an important job to do: the actual beer-making process done at the brewery.
Harvest season is an all-hands-on-deck type of situation. Many farmers even live on the property during the season, which starts around the end of August and can last through September, as their days consist of two 12-hour shifts, seven days a week.
Before each growing season, farmers burn down the fields and start completely anew, a process Atkins likes because he says it gives a sense of rebirth, no matter how good or bad the previous yield was. Every year is a new beginning with just as much promise for great beer as the last.
The Complete Guide on How to Grow, Harvest & Dry Hops at Home
People have been harvesting hops to make delicious homemade beer for thousands of years.
Honestly, nothing much has changed (besides the Space-Age stainless steel technology used to mash, sparge, and boil genetically engineered plants perfectly).
In this complete guide on how to grow hops at home, we cover everything from the perfect location to how to dry and freeze them for later use.
Now, you’ll be able to serve up homebrew that is actually 100% made from scratch.
What is a Hop?
Hops are in beer—that makes them pretty important to begin with.
These cone-shaped flowers are the main ingredient used to flavor beer, mostly because of their flexibility, sense of bitterness, and preservative effect on the beverage.
What do hops look like?
A picture is worth a thousand words right? Best to take a look at the image on the left.
There are as many types of hops as there are brands of beer (slight exaggeration), and each produces its own distinctive personality. That’s the main reason why modern beer brewers love them so much.
So now that you can’t wait to start picking your own batch off of your fence (and everywhere else in your yard), let’s get into how to grow them.
We’ll cover the process in 3 main phases:
And a bit of freezing thrown in for good measure.
“Hops contain an essential oil with a very bitter flavor. This bitterness counters the sweetness from the malt to create a more balanced beer, and it also acts as a preservative.”
– Emma Christensen, Brewer
1. How to Grow Hops?
All you need to get started are some rhizomes (roots cut from a hop plant), some sunshine, and space to grow. Chances are you’ve got the latter two already (we hope), so let’s start with rhizomes.
Let’s start with how to get hops.
1.1 When to Buy
Rhizomes are available in March/April at most home growers/outdoors shops. Some of the most popular varieties may have to be pre-ordered, but usually just putting your name on the mailing list will do fine.
As soon as they arrive, you’ll be notified.
1.2 Basic Requirements
Did you know that hops became popular for brewing alcohol in climates where growing grapes wasn’t feasible? Makes sense.
The good news is that hops can grow in pretty much any mild/temperate climate during the summer.
As long as you have a minimum of 4 months frost-free (pretty much everywhere in the USA). Here’s what you’ll need:
- Space: Your hops are going to turn into growing machines (sometimes up to 1 ft. per day), so make you’ve got plenty of room. The ideal site will have direct access to sunlight, plenty of fencing, and open vertical space above (i.e., no power lines).
- Support: You don’t have to sing to your plants, but you should support them as much as possible. Tall poles and twine are best, or, if you really want to be rustic and patriotic, a flagpole is a great idea. We’ve even seen people use clotheslines before.
- Soil: With the advent of fertilizers, most soil is fine for growing plants. Still, you want a Ph between 6.0-8.0 if possible. Manure compost and commercial fertilizers are a must.
Now that you’ve chosen your location, let’s move on to preparing the soil and rhizomes and actually sticking them in the ground.
- Maintain your rhizomes: If you buy them a bit early (before the ground has thawed), keep them refrigerated and mist them lightly on a regular basis.
- Prepare the soil: Mix some topsoil and compost if necessary into your soil with a gardening fork or other tool. Make sure you’ve turned it over well.
- Plant your rhizomes: Stick those bad boys in the ground with the buds facing up, and cover them with about 2 inches of soil.
It’s really that simple. Of course, like all plants, your hops are going to need some TLC. You’ll want to maintain the rhizomes with frequent short waterings.
In the first season, the plant focuses on planting deep roots to survive droughts, so don’t expect too much in year one. Short waterings are enough in the first season.
Next season, you’ll have to focus on longer watering methods like drip irrigation. But anyway, we digress.
If you don’t maintain your hops, your yard will begin to look like that overgrown abandoned house down the street and not in a good way.
Worse, it may lead to pests and plant diseases that will ruin your plant.
So get your green thumb out and get ready to trim branches, plant poles, and mulch your soil to no end.
- Bine: This isn’t a typo. A bine is similar but different from a vine. It is the climbing stem of your hop plant.
- Trellis: A framework of wood or metal for supporting your plants.
Here are a few tips:
- Mulch: Use organic material to mulch the soil frequently. This will control weeds.
- Plant a trellis (or some basic support): We recommend strong poles in the ground to keep it simple. Strong wire also works well. Hop plants can grow up to 30 feet if the support system allows it! If you want to be ambitious, build a full trellis support system or purchase one from a store.
- Select the strongest branches: Wait until the bine is about 1-foot long and select 2 or 3 of the strongest branches. Why? Survival of the fittest. By trimming the weaker branches, you allow the plant to focus on its strongest branches. Also, you avoid entanglement issues. Now that you’ve chosen the branches, wrap them around your chosen support system.
- Trim, trim, and trim: Keep a close eye on your plant and be sure to trim regularly. We mean like 2-3 chutes off of the bine each time. The last thing you need when harvesting your hops is battling a jungle of tangled up arms of a hop plant.
1.5 Pests to Watch Out for
Your neighbors won’t be the only ones interested in what’s going on in your backyard. There are plenty of pests who will set their sights on your garden.
Most are easy to spot, and, with the right insecticides (or plain water), get rid of. Keep an eye out for these two:
- The Hop Aphid: These pale-green pests haunt hopyards and can destroy an entire harvest. A strong blast of water is usually enough to get them off your bines. You can also use commercial insecticides.
- The Spotted Cucumber Beetle: They look a lot like ladybugs but vary in color and size. Commercial insecticides will do the trick too.
Depending on the height of your plant, you may need to jump up on a ladder.
Aside from pests, you need to keep a close eye out for mildew. If you spot discolored or soggy leaves, remove them immediately. If it is severe, you may need to invest in a fungicide.
Once August rolls around, most plants are ready to be harvested.
2.1. When to Harvest Hops?
Late summer nights slowly blend into crisp fall early evenings, and your skyscraping vines are now reaching ever closer toward the dull grey skies.
OK, enough of the theatrics. It’s time for the harvest!
After a few months, your plants should be ready to bear their fruit. Here’s how to tell if your hops are ready to be picked:
- Feel the cones. Are they dry and papery? If so, they are ready to go.
- Lupulin is the main ingredient in hops. When ripe, its yellow powder and aroma should be obvious. Roll the hops in your hand… do they get sticky? Smell the cones? Do they smell aromatic?
- Lastly, try to crush one of the cones. If it springs back to full form, they are ripe.
If all of these tests fail, give them a little bit more time.
As you become more experienced, you’ll get a better feel for things. Be prepared for several harvesting sessions to get the best hops possible.
2.2. How to Harvest Hops?
Now the fun, albeit tedious part happens. For larger plants, you’ll need:
- Long sleeves (the plants can be abrasive)
- Sturdy Gloves
- A ladder (if your plants reach up really high)
- A six pack (hey, your friends aren’t going to come help you for free)
- A large bucket
Picking them is really simple. Just pull (or cut) the bine down and pick them one by one with your hands. Throw them into the bucket and you’re all set.
If you cut down the bines, let them lay on the ground to strengthen their roots. This is only necessary in the first year.
3. How to Dry Hops?
Without getting into the specifics of the science, drying hops is necessary because it gives you more control over the flavors.
According to a study, different temperatures can affect the bitterness of the end result after dry-hopping.
Moist hops are unpredictable whereas dry ones can be manipulated to create all of the extremely delicious beers we enjoy today.
When drying, you have two choices:
- Quickly with high heat: This takes less time but yields lower quality hops.
- Slowly with moderate temperature: Takes longer and requires more care but produces higher quality.
3.1. Methods of Drying Hops
The three main ways are:
Low-tech (preferred): Use a screen and a fan to dry your hops if your batch is small. Wash and dry the screen and lay it on top of a fan on low power.
Make sure the fan is off the ground. One trick is to put several bricks in a square formation and place the fan on top. Then lay the screen on top of the fan and pour your hops on.
Medium-tech: Put them in an oven on a pan. Make sure the oven is on very low heat and keep an eye on them.
In either case, you don’t want the hops to turn brown or dry so much that they break in your hand.
Food Dehydrator: These are a godsend for impatient harvesters. Basically, it’s a kitchen appliance that dries food for storage. It uses a combo of heat and airflow to remove water from food, making it easier to store.
Load the hops in, press the button, and let it sit for several hours. Just don’t let the heat get too high and keep an eye on your harvest.
The reason you don’t want to overdry them is that they will lose alpha acids, which are basically the ingredient that you’ve just done this whole process for.
They are what gives the beer the flavors that we crave. You don’t want to waste your entire harvest season by leaving them out to dry too long!
4. How to Store Hops?
Learning how to store hops is essential.
Thankfully, storing hops is easier than finishing a pint of delicious home brew.
The best way: Place your hops in an airtight, vacuum-sealed bag and toss them in the freezer. This will preserve their alpha acids the best way possible.
Alternatively, you an use glass jars and store them in the freezer.
If you plan to use them instantly, you can also store them in a mason jar in the fridge. Just use them quickly.
Check out the following video for a summary of the entire process:
What Are You Waiting For? Hop To It
There’s no feeling as rewarding as growing your own hops to use in some delicious homebrew. At least not when it comes to beer.
Planting, maintaining, and harvesting hops isn’t all that hard once you get the hang of it. Now that you know how to grow hops at home, you can truly say your beer is made from scratch.
Now that you’ve grown your hops, you must be ready to make your own homebrew. Make sure to check out our page on the best home brewing kits.
These kits are designed to get you started on your brewing adventures.