The ruffly green formerly known as highway median beauty queen is having its moment in the culinary sun, and rightfully so. Kale isn't just a pretty face; she's a hardy, unpretentious sort who plays well with others in the kitchen and is about nutritionally virtuous as it gets. She's the girl next door, an unsung hero now getting her due, from Costco to Whole Foods, Olive Garden to Chez Panisse, Steven Colbert to Dr. Oz.
If you've detected a bias, you're correct. Allow this kale lover to count the myriad ways...
A Brief History
You can't talk about kale without talking about cabbage, as both are descendants of a wild cabbage that is more than 2,000 years old. But which came first, kale or cabbage? According to The Oxford Companion to Food, "Kale is the more primitive of the two, and was the ordinary greenstuff of country people in most parts of Europe until the end of the Middle Ages, when the 'headed' cabbages were bred."
In his book, Mediterranean Vegetables, culinary scholar Clifford A. Wright notes that the earliest record of cultivated cabbages - from Greek literature around 600 B.C. - actually is a reference to kale. In fact, not until 16th century Paris would the "first clear reference to head cabbage" emerge.
Although most historians agree that kale is a native of Mediterranean Europe, some have hedged their bets on Asia Minor, the birthplace of its close relative, collard greens. No matter the origin, kale proved itself as a hardy frost-tolerant crop, which explains its migration to northern Europe, where it was the most widely eaten vegetable through the Middle Ages. While it was referred to as "cole" in England, it was known as "kail" in Scotland, where everyone had a "kailyard" that fed both humans and livestock. "Come to kail" was a common expression referring to the main meal of the day.
- Thomas Jefferson experimented with several varieties of kale at his Monticello estate in the early 1800s.
- Kale was central to Britain's Dig for Victory campaign, a World War II effort that encouraged Britons to turn their lawns into edible gardens.
- Kale's recent rise in popularity in this country led to a t-shirt designed by Vermont artist Bo Muller-Moore, who cooked up the slogan "Eat More Kale." Fast-food chain Chick-fil-A came after Muller-Moore in 2011 with a cease-and-desist campaign, claiming that his slogan was somehow too similiar to the company's "Eat Mor Chikin." Muller-Moore's legal woes have earned him celebrity status and he is the subject of a crowd-sourced documentary called "A Defiant Dude" currently in production. (He continues to design Eat More Kale t-shirts.)
- As of this writing, members of the Vermont legislature introduced a bill recognizing kale as the state vegetable.
Botanically, kale is a card-carrying member of the brassica oleracea family, the apparent forerunner of all things cabbage-y, and like collard greens, it's part of the headless/acephala subgroup.
Aside from ornamental kale, (which is best left to highway beautification efforts, in my opinion), there are ample choices for kitchen experimentation, including the ancient Curly varieties, the red-hued and blue-gray Russian cultivars and - my absolute favorite - the green-black ruffles of Tuscan kale (aka lacinato, cavolo nero and dinosaur).
Kale is a cool-weather and frost-resistant crop, which means it's available for up to three seasons, depending on where you live. Home gardeners know that it overwinters nicely and readily sprouts young tender leaves with the arrival of spring.
Like collards, conventionally grown kale is a cause for environmental concern, according to the Environmental Working Group. Due to continued use of a pesticide called organophosphate on leafy greens, both headless cabbages received a "Dirty Dozen Plus" designation in last year's Shoppers Guide to Pesticides in Produce. A known hazard to the nervous system, organophosphate is being phased out but remains legally available.
Because of its skyrocketing popularity, pre-rinsed and trimmed kale is now being sold en masse in bags in supermarket produce sections. As a food safety precaution, we recommend that you rinse bagged kale as thoroughly as you would an unwashed bunch.
Whenever possible, buy organic, particularly at the supermarket, to avoid insecticide residues. And when shopping at farmers' markets or at farm stands, talk to your grower about production methods. Often growers who can't afford organic certification are actually farming without chemicals. (See our veggie rule of thumb*.)
If you're a numbers person, kale is your kind of vegetable: Along with collards, mustard greens and watercress, kale scores a perfect 1000 on the Aggregate Nutrient Density Index (aka ANDI). Designed by Dr. Joel Fuhrman, ANDI is a measurement that scores nutrients per calorie which has been implemented by Whole Foods Market.
For the rest of us, here's what makes kale a nutritional super star: Anti-inflammatories in the form of Omega-3 fatty acids and Vitamin K; antioxidants in the form of carotenoids (which were recently studied for their link to positive mental outlook, Vitamins C and E, as well as dozens of flavonoids (found in the pigments); cancer-fighting glucosinolates, just to name a few. For just 36 calories, one cup of kale contains three grams of fiber, 93 mg of calcium, 2.5 grams of protein. Not too shabby.
Kale's only caveat are its level of oxalates - a possible concern for people with kidney stones - so check with your doctor if this is a concern. According to the nutritional portal WH Foods, its 'goitrogenic' tendencies are overblown, and it does not interfere with thyroid function, contrary to popular belief. Again, check with your doctor as needed.
What to look for
Stay clear of wilted or browning leaves. Leaves and stalks should be firm and dry versus wilted and mushy.
Kale holds up for up to five days if loosely wrapped in the refrigerator; any longer than that and the leaves tend to toughen.
What to Do with It
Remember Forest Gump's friend Bubba, who sees no end to the things you can do with shrimp? That's how I feel about kale: Steamed, stir-fried, roasted, raw and "massaged," kale smoothies, kale chips, wilted into soup, mashed with potatoes and one of my favorite discoveries, kale pesto. Whatever you decide, I recommend removing the middle rib, which can be tough and unpleasantly fibrous, even when cooked. You can do this by hand, with a knife or kitchen shears.
Wait until after the ribs have been removed to wash leaves, and for raw salads, thoroughly dry. Arrange dried leaves into a mattress-like pile, roll up like a cigar and cut into ribbons. Smaller pieces are easier to "massage" and tenderize.
Emerald green, thick and rich, kale pesto has become a staple at our house, making its way onto sandwiches, on pizza dough, pasta and smeared onto roasted sweet potatoes. Ready, set, kale...
Excerpted from The Meat Lover's Meatless Celebrations by Kim O'Donnel by arrangement with Da Capo Lifelong, a member of the Perseus Books Group. Copyright 2012.
4 cups water
1 to 11⁄2 teaspoons salt
4 cups Tuscan kale that has been stemmed and chopped coarsely
1⁄4 cup unsalted walnuts or almonds, chopped
2 cloves garlic, minced
1⁄2 cup olive oil
1⁄2 cup grated Parmigiano-Reggiano cheese (optional)
Freshly ground black pepper
Bring the water to a boil. Add 1 teaspoon of the salt, then add the kale. Cook uncovered until tender, about 10 minutes. Drain the kale under cold running water. With your hands, squeeze as much water out of the kale as possible; you'll end up with a green ball about the size of a tennis ball.
In a blender or food processor, combine the nuts and garlic, and whiz until pulverized and well mixed. Add the kale and process until well blended; the mixture may even look a little dry. Pour in the oil and blend. The mixture should be glistening and will have a consistency that is somewhat textured, somewhat loose. Taste and the remaining 1⁄2 teaspoon of salt, if needed.
Transfer the pesto to a small bow and stir in the cheese (if using) and the black pepper.
Pesto keeps well in an airtight container in the refrigerator, for up to a week.
Make about 1 cup.
(*Vegetable rule of thumb: We think that first and foremost, in terms of nutrition, people should eat lots of fruits and vegetables whether they are organic or not. The EWG's guide is a handy list, but we will point out here that the impacts of pesticides are not limited to your ingestion of them -- agricultural chemicals also affect farmworkers and local waterways, both good reasons to buy organic, even those vegetables that carry a light pesticide load. Also, it has been demonstrated that produce grown by small-scale farmers, even those who are not certified organic, tends to have a lighter pesticide load than its industrially-produced counterpart, owing to industry's tendency toward large monocrops.)
This post was originally published in February 2013.