Why is cauliflower purple?

My Cauliflower Turned Purple: Reasons For Purple Tint On Cauliflower

Cauliflower is a member of the Brassica family grown for its head or curd, which is composed of a cluster of flowers. The head is most often pure white to a slight cream in color, but what if there is a purple tint on cauliflower? Is it safe to eat purple cauliflower?

Help, My Cauliflower Turned Purple!

It happened to me the first time I grew cauliflower in my home garden; my cauliflower turned purple. It was my first foray into vegetable growing, about 20 years or more ago. Everything was an experiment.

The Internet was more or less non-existent, so I often relied on my mother or aunt to clue me in on gardening problems and possible solutions. Thankfully, they told me this purple tint on cauliflower was not a disease, fungus or pest.

Cauliflower is a cool weather veggie which thrives in the cool temperatures of spring and fall. As mentioned, it is grown for its whitish to cream head or curd. But cauliflower naturally has a range of colors, even tending towards purple, yellow, red or blue tints. This purple color in cauliflower is caused by the presence of anthocyanin, which is exacerbated by sun exposure. It is a harmless water soluble pigment found in colorful foods such as grapes, plums,

berries, red cabbage and eggplant. Certain varieties, such as ‘Snow Crown,’ have a stronger propensity for a purple color in cauliflower heads.

Preventing Cauliflower with Purple Tinge

To prevent growing cauliflower which has a purple tinge to it, purchase a self-blanching variety which has been developed to reduce problems with curd tinting, or blanch or cover the head as it is developing. Also, schedule the maturation of the cauliflower for cooler months such as September and October.

Lengthy, hot summer days will cause a purple color in cauliflower heads; you may even see leaves sprouting out of the curd. If this has already happened, there’s nothing to be done about it except to take note for next year’s crop. To blanch a cauliflower head, tie the outer leaves over the developing curd when it is 2 inches across, securing them with a clip or gardening twine. The leaves will shield the developing curd from the sun and allow it to maintain its whitish coloration.

Planting time for cauliflower is also an important consideration to avoid the formation of purplish curds. Cauliflower needs daytime temps of between 70-85 F. (21-29 C.) but with an early enough start time for a long enough growing season to support maturation of a large head. If you plant too early, however, a late season frost can kill the young cauliflower. You may need to look for early maturing or late maturing varieties, depending on the climate in your area and the length of your growing season. The earliest varieties mature in just 60 days, and in some regions, you can get an early harvest and then replant in June for a fall harvest.

Is It Safe to Eat Purple Cauliflower?

If it’s too late and the cauliflower curd is already tinged purple, don’t despair. Purple cauliflower is perfectly safe to eat. It may have a bit of an “off” flavor and, as such, you may want to use it raw; cooking it will only increase the “off” flavor. Heating the purplish florets will also change the color from purple to gray or slate blue, especially if your water is hard or has an alkaline pH — not the most appetizing hues. If you can’t stand raw cauliflower and want to cook it, add a bit of vinegar or cream of tartar (tartaric acid) to the water to minimize the color change.

The Many Colors of Cauliflower – Purple, Green, Orange, and White

Green, yellow, and purple cauliflower

Have you been seeing something in the supermarket or famer’s markets that looks like cauliflower but instead of the traditional white, the heads are purple, orange, and green? Colored cauliflower started popping up in the markets about 10 years ago and have increasingly become more popular and readily available. What are these colored cauliflowers? How do they taste? How to prepare them so they retain their color?

White cauliflower used to be the only option. The colored cauliflowers, like the white variety, are members of the cruciferous vegetable family. They have a similar texture and taste—mild, sweet, and nutty. The major difference is their color and with color, a slight difference in nutritional value.

White cauliflower matures creamy white if the head is void of direct sunlight. Older cultivars need to be blanched (inner leaves are tied loosely over the small heads to reduce the amount of light penetration) to prevent the sun from turning white cauliflower to yellow. Newer cultivars are self-blanching as the plants produce inner leaves that hug the heads tightly preventing light penetration. No blanching is required for the colorful varieties.

Purple cauliflower gets its color from anthocyanin, a naturally occurring phytochemical that is also found in other red, blue, or purple fruits and vegetables, as well as red wine. Carotenoids are responsible for the color in orange cauliflower; carotenoids are also found in carrots, squash, and other yellow vegetables and fruits. Orange cauliflower actually came about as a genetic mutation that allows it to hold more beta carotene than its white counterpart. Green cauliflower, also known as broccoflower, is a hybrid of broccoli and cauliflower. Green cauliflower contains more beta carotene than white cauliflower, but less than broccoli.

Colored cauliflower can be eaten raw, roasted, grilled, sautéed or steamed. Cooks Illustrated experimented to find out the best method of preparation for holding color. They found that the orange cauliflower proved to be the most stable; the orange pigments are not water soluble or sensitive to heat. The chlorophyll in the green cauliflower is heat sensitive just like broccoli; overcooking will cause the cauliflower to become brown. The anthocyanins in purple cauliflower leach out in water which dulls it’s color; color is better retained with dry heat such as roasting, grilling, or sautéing.

There are lots of recipes available online for preparing the colored cauliflowers. Enjoy the color!

Marlene Geiger

I am a graduate of the University of Nebraska-Lincoln with a BS in Home Economics Education and Extension and from Colorado State University with a MS in Textiles and Clothing. I enjoy spending time with family and friends, gardening, quilting, cooking, sewing, and sharing knowledge and experience with others.

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A simple Sicilian recipe for Purple Cauliflower Salad (purple cauliflower is optional!) with kalamata olives, capers, fresh herbs, a grain of choice, topped with pickled red onions. Add Marcona almonds or shaved pecorino to add richness, or keep it vegan! Either way, you’ll love the Sicilian flavors in this recipe!

I stumbled on the most beautiful purple cauliflower at the farmer’s market the other day. I still marvel at how nature produces such remarkable hues, it’s kind of incredible, really. Anyways, this is what became of the purple cauliflower and as I type I’m munching on the leftovers. So tasty! Know that you can make this salad with regular cauliflower, or even a pink one – whatever strikes your fancy.

But if the opportunity arises which, I have a feeling it will – because well, that is how the universe works- where the most beautiful purple cauliflower catches your eye, now you have something to make with it!

And bringing something new and different into the kitchen even as simple as a purple cauliflower makes cooking delightful. So prepare yourself for delight, friends. I’m so excited to see how many of you stumble on a purple cauliflower this week!

If I were a bride, I would have these as my centerpieces. I would hold one as my bouquet. Ok maybe a bit much, but you get the idea, they really are flowers!

Roast the cauliflower and cook your grain of choice.

Today I picked black rice, but feel free to use quinoa, farro, freekah, wheat berries, wild rice… anything you like!

You can toss everything into a big bowl along with the dressing, or you can layer the salad as I do here for a pretty presentation, to show off the cauliflower – perfect if taking to a potluck or gathering.

Layer the cooked grain on the bottom. Add the roasted purple cauliflower, olives, capers.

Sprinkle with the scallions and herbs.

Add the pickled red onions, and spoon the dressing over top!

Toss right before serving.

So easy, so fun to make.

Go visit your local farmer’s market, find the purple cauliflower of your dreams and give this Purple Cauliflower Salad a try this week! Hope you are having a joyful week. Hint: it’s in you. The joy, I mean… find it!;)

xoxo

Related:

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Make-Ahead Vegan Salads!

Purple Cauliflower Salad- Sicilian Style

Purple Cauliflower Salad (Sicilian Style!) with kalamata olives, capers, grains parsley scallions and pickled onions. This vegan healthy salad is easy to make and keeps for several days, perfect for meal prep!

  • Author: Sylvia Fountaine
  • Prep Time: 20
  • Cook Time: 30
  • Total Time: 50 minutes
  • Yield: 6 1x
  • Category: salad, vegan salad
  • Method: roasted
  • Cuisine: Italian

Scale 1x2x3x

Ingredients

  • 1 head cauliflower, purple if possible
  • olive oil to coat
  • 1/2 teaspoon salt
  • zest of one lemon
  • —–
  • 2 cups cooked grain- black rice, quinoa, freekah, farro, etc….
  • 2 scallions, sliced
  • 1/2 cup sliced kalamata olives
  • 2 tablespoons capers
  • 1/2 cup Italian parsley, chopped

Dressing:

  • 1/4 cup olive oil
  • 2 tablespoons red wine vinegar
  • 2 cloves garlic, minced
  • 1/2 teaspoon salt
  • 1/2 teaspoon pepper

Optional Garnishes: Pickled onions, marcona almonds, chili flakes, shaved pecorino

Instructions

Preheat oven to 425F

Set grains to cook on the stove. Cook and cool to room temp.

Cut cauliflower into bite-sized florets, lightly toss in olive oil, salt and lemon zest. Spread out on a parchment-lined baking sheet. Roast 25 minutes, or until fork-tender, turning halfway through. Let cool.

Make the dressing, whisking all in a bowl.

Feel free to toss salad ingredients the dressing in a bowl or layer them in a shallow bowl. If layering, start wth the grain, add the cauliflower, olives, capers, scallions, parsley, pickled onions, optional almonds/pecorino and sprinkle with chili flakes.

Nutrition

  • Serving Size: 1 cup

Keywords: purple cauliflower salad, purple cauliflower recipes, roasted cauliflower salad, vegan cauliflower salad, cauliflower salad recipes, cauliflower recipes healthy, Italian cauliflower salad

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The Many Colors of Cauliflower

White cauliflower is by far the predominant type of this cruciferous vegetable, but purple, orange, and green varieties also exist.

  • White cauliflower. In order to prevent the sun from turning white cauliflower yellow, farmers sometimes tie the biggest leaves over the head (also known as the “curd”) when it reaches the size of a tennis ball. Note that cooking white cauliflower in aluminum will cause it to turn yellow, while cooking it in cast iron results in a brown or blue-green color.
  • Purple cauliflower. This may be referred to as Sicilian Violet, Violet Queen, or Graffiti Cauliflower. Anthocyanin, the phytochemical responsible for purple cauliflower’s vibrant hue, is also found in other red, blue, or purple fruits and vegetables, as well as red wine.
  • Orange cauliflower. Also called Cheddar Cauliflower or Orange Bouquet Cauliflower, this type of cauliflower owes its color to a genetic mutation that allows it to hold more beta carotene than its white counterpart.
  • Green cauliflower (broccoflower). This is a hybrid of broccoli and cauliflower. There are two variants, one shaped like regular cauliflower, the other (Romanesco) with pointed, conical spiraling clusters of florets. Green cauliflower contains more beta carotene than white cauliflower, but less than broccoli.

Keeping Color in Colorful Cauliflower

Not so long ago, white cauliflower was your only option at the supermarket. Nowadays the produce aisle is aglow with hybrid varieties bred to have high levels of particular naturally occurring pigments. An abundance of carotenoids color orange cauliflower; extra chlorophyll creates green cauliflower, and a plenitude of anthocyanin compounds produces the purple brassica. Color differences aside, we found that they all shared the same mildly nutty-sweet flavor. But does cooking dull their color? We boiled these varieties in water and sautéed them in oil to find out.

The carotenoids in orange cauliflower proved the most stable. These pigments are not water-soluble or sensitive to heat and stayed vibrant when boiled or sautéed. Though the chlorophyll in green cauliflower is heat sensitive, the vegetable turned tender before it faded or turned brown, whether boiled or sautéed. The water-soluble anthocyanin compounds in purple cauliflower were the most sensitive; when we boiled the vegetable, they leached into the water and dulled its color if cooked past crisp-tender. Happily, sautéing didn’t impact the color at all.

In sum, orange cauliflower will hold its color no matter how (or how long) you cook it and green cauliflower will stay green as long as you don’t overcook it. Stick with sautéing purple cauliflower to prevent its color from fading or make sure to blanch it until just crisp-tender.

Cauliflower stems turning purple

Hi, I grew broccoli and cauliflower from seed and transplanted them into the garden on Memorial day, exactly three days ago. My starts were thriving, bright green and sturdy. They are still sturdy and green, but today, exactly three days after transplanting them, I noticed the cauliflower stems are starting to turn purple and the small new leaves sprouting from the middle of the plants are also coming up purple. The broccoli stems are still green, but the leaves are also starting to have a purple-ish hue. I know that purple can be a sign of phosphorus deficiency, but I tested the soil and it says it is adequate/sufficient in phosphorus. It’s also freshly layed compost in which the plants are planted in. I also don’t understand how quickly (just 3 days) the plants could have changed. I fertilized the plants with 5-1-1 fish emulsion as that is all I have on hand. Tomorrow I plan on getting a phosphorus fertilizer to feed them. I should also mention that the plants hardened off for 2 weeks in hot and cold weather, so I’m not convinced it’s a temperature issue (cold weather making it unable for nutrients to be brought up from soil). But it could be since we had a colder, misty rain Tuesday and some rain overnight and this morning as well. And the plants never sat outside at night under the rain because they were under the porch at night. I live 900 ft up in elevation in Washougal, so temperatures are a bit lower than Portland. The I’ve babied these plants since the beginning and am sad that they are changing all of a sudden. I’m racking my brain and the internet as to what could be wrong and cannot get an answer. I even started to question the quality of the compost I had delivered. I’ve done tests on the compost and the pH is about 6-6.5. Potash and potassium seem to be sufficient, and nitrogen is unclear as the tester is unclear. Any advice would be so appreciated. Thank you SO much! Best, Christina

Purple Cauliflower. on the image to see a slideshow of this week’s Purple spec. load.

I was sent this pic through the week with the enquiry: “Why are my Cauliflowers turning purple?”
I don’t have personal experience of this issue but Mark with many years of experience in the UK vegetable industry was not surprised to see some purple discolouration. Having done a little reading (none of it scientific) Cauliflower is naturally coloured, it’s through selection and breeding that white “curds” have been developed. When the plant is stressed some varieties will revert to their original colours. From my point of view this is a perfectly handsome Cauliflower and I think the colouring will “cook out”, it is certainly still perfectly edible. Growers recommend folding and pegging leaves over the curds to create a protective scarf to prevent sun scald & frost burn, I don’t know if this will affect curds reverting to purple.

While we were discussing Caulis Mark used the term “Buttoning”. I hadn’t heard of buttoning previously but a quick search indicates that buttoning describes exactly the problem reported earlier this year by another frustrated grower of Cauliflower Baby White. Buttoning describes Caulis or Broccoli that prematurely set heads that remain seriously undersized. It turns out that buttoning is another stress reaction by the plant. This response can be caused by any number of stresses: too wet, too dry, too hot, too cold, hungry, too many weeds, etc. Mark has also experienced Baby White Caulis buttoning in his home garden so it may be it is a variety that is particularly susceptible, which is disappointing because it is quite an expensive hybrid. Mini or Baby Cauliflower were bred specifically for the restaurant trade to produce single serve Cauliflowers, but the buttoned heads are just no value to anyone.


“Buttoned” Cauliflower also showing signs of hosting caterpillars and possibly Downy Mildew on the yellow lower leaf.

Cauliflower at a glance
Position. Full sun
Soil. Prepare thoroughly, add organic fertilizer generously. Caulis prefer a neutral pH so they they will appreciate some lime, especially if the soil is regularly used for vegie gardening.
Visitors. Look out for Cabbage White Butterfly, especially in warm conditions. During cooler months watch for Aphids.
Plant selection. Tough older plants will usually respond well to moving into fresh soil or potting mix but don’t try transplanting plants that already show signs of setting their curds… it’s too late. A few chewed holes is not something to be frightened of, check for grubs & feed them to the chooks. Pale yellow leaves with dark furry growth on the underside of the leaves indicates Downey Mildew, this is mostly a problem for young seedlings. Planted into ideal conditions Cualis will outgrow the problem but badly infested seedlings planted into less than ideal conditions will struggle.
Always check for healthy root growth.
Fun Fact: “Colli Flowers” were planted at Norflolk Island in March 1788.

Why Does Cauliflower Turn Purple & Have Fuzz on It?

When vegetables begin to develop problems — or at the very least, begin to look odd — more than one factor may be involved. In the case of cauliflower (Brassica oleracea spp.), for example, you may find the head a different color than the classic white, while also noticing unusual growths on the plant. If the head is purple and leaves or stems are looking fuzzy, chances are the causes of the two unusual characteristics are unrelated.

Check the Variety

The most obvious cause of a cauliflower developing a purple head is that you’ve unwittingly purchased a purple cauliflower variety. Technically, this type isn’t a cauliflower at all, but does taste like common white cauliflower. Check the labeling information on your seedling or seed packet. Varieties such as “Purple of Sicily” cauliflower are, botanically speaking, purple broccoli types (Brassica oleracea spp), although their heads develop cauliflower-like curds. Eat them raw or cooked. When cooked, they will turn a broccoli green.

Sun Exposure

When white cauliflower plants turn purple, it’s likely that they have been exposed to the sun’s rays without protection. Cauliflowers do best in sunny locations, but only when planted in time to mature during cooler months. At the height of summer, high heat and direct exposure to the sun’s rays sometimes result in an increase in pigmentation, especially in the vulnerable plant heads. The curds can turn a purple-red color. To keep curds creamy-white, take the protective measure known as blanching. When cauliflower heads are blanched, their heads are protected by a covering. Often the plant’s leaves are large enough to cover the heads, especially if held in place with twine or even a clothespin. Paper bags fastened around the heads can also keep cauliflower curds from turning purple.

Purple on Stems

If your entire plant hasn’t turned purple, but only parts of the stem, a disease may be indicated. Although cauliflower isn’t as susceptible to the disease known as black leg as cabbage is, it is possible for cauliflower to contract the fungal disease. If you find brownish spots on the stems of some of your cauliflower seedlings, check to see if they have dark purple edges, which indicates black leg. Remove the affected seedlings immediately. In future years, do not grow cauliflower where other brassica crops, including broccoli and cabbage, have grown previously.

“Fuzzy” Diseases

Some fungal diseases can cause a fuzzy or “cottony” look on cauliflower plants, especially the foliage. If the leaves are fuzzy underneath and have yellow-to-brown spots on top, downy mildew may be the culprit. Rainy, cool springs and too-close plantings can contribute to the problem. Powdery mildew, which gives leaves a fuzzy aspect on both sides of leaves, can appear even in dry weather, especially if the cauliflower is too closely spaced. White mold, a third fungal disease, gives a fuzzy look to both stems and leaves, and can cause wilting and rotting of plant parts. The primary cause of white mold is soil that doesn’t dry off on the surface.

Prevention

Planting cauliflower in raised beds, and at a generous spacing, may reduce the incidents of downy mildew in future years. The increased air circulation resulting from wider spacing is also a good control for powdery mildew, as is planting in a sunny area and using slow-release fertilizer. If your garden practices seem to be encouraging white mold, use raised beds, perhaps in combination with drip irrigation that wets soil below the surface. Spacing the plants farther apart can also cut down on white mold problems. Whatever the type of fungal “fuzziness” that seems to be causing your cauliflower problems, destroying affected plant parts or seedlings when they appear may help prevent spread. Growing cauliflower and other brassicas in a different part of your garden each year can also halt the spread of disease.

Who knew cauliflower could be so purple? The unusually colored vegetable started out as an accidental mutation and has become a new favorite for chefs and home cooks alike because of its sweet taste — but we bet you didn’t know the vivid cruciferous veggie has something in common with your favorite red wine.

Where Did Purple Cauliflower Come From?

According to a fact sheet from the College of Agriculture and Life Sciences at the University of Arizona, purple (and other colored cauliflower) began as a colorful accident. The first colorful cauliflower was actually an orange one, discovered in a Toronto field as a single, small, “mutant” plant among normal white ones. Unusually colored plants “are the results of traditional selective breeding — where different strains have been crossbred and crossbred until these strains have been created,” the University of Arizona says. By crossing the “mutant” plant with normal ones, scientists are able to create cauliflowers in different varieties. “They are not genetically engineered but rather a mixture of heirloom varieties, naturally occurring accidents and the hybrids grown from them,” the fact sheet explains.

Why Is Purple Cauliflower Purple?

The colorful cauliflower varieties come in orange, purple, and green. But what, exactly, causes the vivid purple color in purple cauliflower? According to the University of Arizona, purple cauliflower “gets its distinctive deep lavender color from anthocyanins, the antioxidant also found in red wine.”

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What Does Purple Cauliflower Taste Like?

Purple cauliflower, also known as graffiti cauliflower, “has a milder flavor than white cauliflower — it’s sweeter, nuttier, and without the bitterness sometimes found in white cauliflower,” the university says. When cooked, it typically retains its color, though if it’s overcooked, it can turn a little green.

The vegetable is a little more seasonal than the easy-to-find, year-round white cauliflower, so check with your local grocers to find out the best time of year for colorful cauliflower in your area.

Image Source: Unsplash / sheilajoy

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