I think mustard greens suffer from an inferiority complex - they haven't enjoyed a culinary renaissance like kale; they don't have the romantic Italian provenance of broccoli raab, nor the Southern panache of collard greens. I've noticed that in my community garden, folks are quick to plant the veggie (they are super easy to cultivate and don't require much garden-y oversight) but not so quick to harvest it. But they certainly shouldn't be ignored: their peppery bite is perfect in summer salads, awesome when tossed in with legumes like lentils and delicious when sautéed like spinach.
A Brief History
Mustard has been cultivated for centuries across Asia and Europe for both its edible seeds, ground and made into mustard (the condiment) or pressed for their oil, along with its leaves (and even stems). There are several different types of mustard, some of which are native to central Asia - probably somewhere in the Himalayan region - and some that are native to Europe. Food historian Alan Davidson notes that mustard seeds have been found in ancient Greek archeological sites; ancient Greek historian Herodotus wrote of their cultivation as early as the 5th century BCE. In Europe, mustard plants have primarily been utilized for their seeds to make mustard (which Davidson notes has been important there for centuries because it is one of the few spices that can be locally grown), though leaf mustard was, and is, also eaten. (Apparently, in Medieval Europe, courts and monasteries often employed a person, called a mustardarius, whose sole job was to oversee the growing and making of mustard.) China is one of the major secondary sources of genetic variation of the mustard plant, according to botanists, centered primarily around the Sichuan region. (This basically means that mustard has been cultivated there for a very, very long time.)
- Those of us who grew up in the 80s remember well the catch phrase: "Pardon me, would you have any Grey Poupon?" The condiment ("so fine, it's even made with white wine!") is made from brown mustard seeds grown in Canada. Here's an extended (and rather violent) version of the original commercial and the even-better Wayne's World version. And for those of you not quite so old, there is also a Lil Wayne song that references the mustard. You're welcome.
- Mustard plants have been successfully used in phytoremediation, the use of plants to remove toxic substances (like heavy metals) from the soil.
- Mustard greens are increasingly used as a winter crop cover. They are cold hardy, grow rapidly and even have natural chemical compounds that may help combat soil-borne diseases and weeds.
- Mustard oil, used extensively in some South Asian cuisines, is banned in the US for culinary purposes (though it is legal as a massage oil). The FDA's reason for the ban is that the erucic acid found in the oil causes "nutritional deficiencies" and "cardiac lesions" in test animals, although there is some evidence on the pro-mustard oil side that bringing the oil to the smoke point greatly reduces some of these negative effects.
Mustard is member of the impressive Brassica family, a group the Real Food gang has written about extensively (the family includes cabbage, collards, bok choy, kale and radishes). It is primarily Brassica juncea that are eaten as greens, though it's worth mentioning two other types: B.nigra (black mustard, used primarily for the condiment) and Sinapsis alba (white or yellow mustard, also used primarily in condiment-making, but also eaten as a green veggie). Brassica juncea is divided into two major subtypes - B. juncea var. juncea (also known as "brown mustard" or "Indian mustard") and B. juncea var. rugosa (aka "Chinese mustard"), though there are many regional sub-variants. (My favorite is mizuna, B.juncea var. japonica.) All types of mustard are quick to grow from seed, easy to cultivate and naturally pest resistant.
Mustard greens are primarily a cool season veggie and are at their peak in late spring to early summer. Hot weather causes the plants to bolt and their greens to turn unpleasantly bitter. A fall crop is often planted because mustard is frost-resistant and easily overwinters in temperate areas.
According to GMO Compass, there have been several field trials of genetically modified (GM) mustard plants (of various species/sub-species) in several different countries, including in the US, but none have yet become commercially viable. The good news: mustard greens don't appear on the Environmental Working Group's Guide to Pesticides in Produce. They aren't bothered much by pests, but if you are concerned about pesticides, do check with your local mustard farmer about his/her growing practices to be sure that pesticides weren't used.
Leaf mustard comes in an array of shapes and sizes. At many markets, the ruffled-edge, bright green, large-leaved mustard called Southern Giant is probably the most common, but you can see the range of mustard green types here: they vary from small leaved to large; from yellow-green to purple to deep, dark green. Some varieties, like Japanese mustard (mizuna), have thin, deeply serrated, small-ish leaves with thin stems; others, like Red Giant, have softly rounded, very large leaves with very thick stems.
What to look for
For all types of leaf mustard, look for perky greens with no wilting and no mushy or black spots. Also steer clear of mustard greens with yellowing or browned leaves.
Nutrition and effects on the body
Like a lot of greens, mustard is super good for you and you should eat it all the time. One cup has over 500 percent of your daily vitamin K intake, necessary for blood and bone health. The greens are also a great source of vitamin A, vitamin C and folate, and contain decent amounts of calcium and manganese. They even have calcium and protein! And, of course, mustard greens are high in fiber and low in calories.
Mustard seeds have been used for centuries for various ailments. A mustard plaster, wherein mustard seeds are ground up, spread on a cloth and applied to the skin, was traditionally used to treat lung infections and other respiratory problems.
The glucosinolates in mustard greens - the chemical compound that causes the greens' characteristic bitter bite and is responsible for their natural insect-fighting properties - seems to also be a natural cancer-fighter. High consumption of mustard greens and their Brassica brethren has been linked to reduced risk of certain cancers, including prostate. And one more bonus: according to the horticulturalists over at Purdue University, eating mustard greens "may impart a body odor repellent to mosquitoes." Fights cancer and mosquitoes - are mustard greens the perfect food?
What to Do with It
Mustard greens are equally at home raw, cooked and even fermented and pickled (check out the preservation section, below). I love young mustard greens tossed into summer salads; their peppery bite adds a sharp note that I like with more mild lettuces, like Bibb. Older, larger mustard greens are better cooked, pickled or fermented. If you're not a fan of the peppery bitterness of mustard greens, look for young (small) leaves or less-bitter varieties, like mizuna. Because mustard greens are more tender than their leafy-green Brassica family members collards and turnip greens, they need far less time to cook.
Mustard greens can be steamed, tossed into soup, sautéed (like spinach or Swiss chard), stir-fried or braised. Sub mustard greens for spinach or Swiss chard in recipes and see what you think - their peppery flavor is much reduced through cooking. The greens pair deliciously with beans (especially white beans and lentils), pork (especially ham hocks), other dark leafy greens (like spinach, collards and turnip greens), tofu, garlic, onions and citrus. Adding fat, salt and a little acid (like vinegar or lemon juice) also cuts the bitterness of bitter leafy green vegetables like mustard greens. Want more? Here's a great mustard green recipe roundup from the Kitchn.
Mustard seeds are used extensively in Indian cuisine, usually fried in oil and added to dishes like Potatoes with Mustard Seeds (my fave). They are also, of course, made into mustard (the condiment) - of which there are many, many variations, from course-grained brown to the yellow ballpark mustard ubiquitous in the US (and incidentally traditionally colored yellow with turmeric). Making your own mustard is actually pretty easy - as David Lebovitz shows us in this post.
Wrapped in a barely damp paper towel and stuck in an open zip-top bag in the crisper drawer of your fridge, mustard greens will keep for 3-4 days.
Stretching your fresh food dollar though preservation
Mustard greens take super well to preservation, especially pickling and lacto-fermentation. In many cuisines, including Indian, Chinese (especially Sichuan), Japanese, Vietnamese and Thai, the greens are pickled and used a condiment, side dish or added to soup. (Some leaf mustard varieties have thickened stems that are also pickled.) Here's a delicious-sounding pickled mustard green recipe from Hunter Angler Gardener Cook and a Vietnamese pickled mustard greens recipe. The greens can also be successfully frozen - here's a video that details the process.
Spicy Mustard Greens with Garam Masala
This is a quick and easy dish; the coconut milk tames some of the bitterness of the greens. I like it best served with rice, but it would also be delicious with chapatis or even quinoa. If you can't find garam masala, an Indian ground spice mix, sub curry powder (though the flavor will be a bit different). If spicy isn't your bag, omit the green chile or the optional cayenne. (Of course, if spicy IS your bag, feel free to add more than the optional pinch of cayenne!)
2 tablespoons ghee or olive oil
1 green chile (such as Serrano), stemmed and sliced into thin rings
1 clove garlic, pressed (or smashed into a paste with the side of a knife)
1 teaspoon garam masala, plus additional for serving
Pinch of cayenne pepper (optional)
1 bunch large-leafed mustard greens, very thick stems removed, roughly chopped
1/3 cup coconut milk, well stirred
Lime wedges, for serving
- In a medium, heavy sauté pan, heat the ghee or olive oil over medium heat until hot but not smoking.
- Add the garlic and green chile and sauté for 1 minute. (Do not let the garlic brown.)
- Add the garam masala and sauté for a few seconds. Add the mustard greens, a pinch of salt and stir well to coat.
- Stir in the coconut milk. Cover and let simmer for 3-5 minutes, or until some of the coconut milk has absorbed and the greens are tender.
- Transfer to a serving platter. Sprinkle with a pinch of garam masala. Serve warm with lime wedges for squeezing.
Serves 2-3 as a side.
(*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.)