The first time I saw kohlrabi was about 10 years ago at my local food co-op. I had just joined the co-op, and at the time my root vegetable repertoire was pretty limited. Of course, I was intimately familiar with the mighty potato, but the more esoteric root veggies still stymied me, especially the knobby, weird-looking kohlrabi. (OK, I'll admit that back then, even beets were pretty exotic to me. I've come a long way.) I had absolutely no idea what kohlrabi tasted like or what to do with it. Also, kohlrabi is not really a root vegetable -- but more on that below.
My indoctrination to kohlrabi consumption began gradually, starting with kohlrabi pancakes -- what vegetable doesn't taste good mixed with a little flour and eggs and fried up in olive oil and butter? -- but now includes kohlrabi slaw, roasted kohlrabi and even raw, thinly shaved kohlrabi. I've come to appreciate the crunchy, sweet, cabbage-y, turnip-y flavor of this funny-looking veggie.
Kohlrabi's origins are shrouded in mystery. The Oxford Companion to Food says that the first trustworthy evidence of its cultivation comes from 14th Century France, although Pliny the Elder, writing in the 1st Century, mentioned a vegetable called a "Corinthian turnip" which may have been the kohlrabi. Several sources I came across indicated that the 4th (or 5th) Century Roman cookbook Apicius mentions the preparation of kohlrabi, but I found no such mention in this fascinating translation.
Kohlrabi's popularity has seemed to wane in the US over the years, though based on its appearance in a number of antique cookbooks I've come across, it was far more common in the recent past.
Kohrabi is a member of the Brassicaceae(also known as Cruciferae) family, that illustrious and versatile group of vegetables that includes kale, cabbage, broccoli, Brussels sprouts, bok choy, cauliflower, turnips, radishes, horseradish, mustard, arugula and rapeseed (a.k.a., canola). Seriously, what would we be eating withoutthe Brassicas?
The kohlrabi "root" is actually the swollen stem of the plant that grows above ground, topped by leaves resembling kale or collards. Fast growing and easy to cultivate, kohlrabi is becoming more popular in the US, but its strongest foothold is in Germany, Eastern Europe and India.
Kohlrabi are susceptible to the same diseases and pests as other members of the cabbage family, so pesticides to control fungi and insects may be applied. The good news is that kohlrabi's relative obscurity -- stateside, at least -- means that demand has not reached the point that thousands of acres of farmland as far as the eye can see are monocropped with kohlrabi. However, kohlrabi relatives kale and cabbage are numbers 12 and 43, respectively (out of 53), on the Environmental Working Group's Shopper's Guide to Pesticides in Produce, so if you are concerned, the best thing to do is ask your local kohlrabi farmer about his or her growing practices (see our vegetable rule of thumb*).
Kohlrabi are available in most US markets from late spring through late autumn. In many areas, the vegetable can only be found at farmers' markets, CSAs and smaller grocery stores (like food co-ops). Note that kohlrabi prefers cooler weather, so summer-harvested kohlrabi may be woodier than those grown in the spring and fall. In warmer climates, kohlrabi may be available into the winter and may even have two growing seasons.
Kohlrabi, like many of its Brassica brethren, are pretty darn good for you. The vegetable is very high in vitamin C and fiber, and is a good source of vitamin B6 and potassium, too. It's also fairly high in minerals, including copper and manganese. Kohlrabi is low in calories, unless you mix it with flour and egg and fry it (recipe below). But hey, everything in moderation.
There seems to be a significant link between cruciferous vegetables and cancer prevention. Several of the phytochemicals (chemicals found in plants) found in the Brassica family have been found to inhibit cancer growth. Frequent consumption of the vegetables has also been found to preventsome cancers, including oral cancer, esophageal cancer, breast cancer, bladder cancer and kidney cancer. So get cracking on peeling that kohlrabi!
The kohlrabi bulb should be firm with no spongy bits and no visible brown spots. If leaves are still attached, they should be sprightly, green and free of wilt or mold.
Meta Given's Modern Encyclopedia of Cooking, from 1947, is a wealth of information about selecting kohlrabi. In the cookbook, Givens says that, grown under ideal conditions (cooler weather and abundant moisture), "the ball is so tender that the skin is easily pierced with the thumbnail and strips off like the skin from a tangerine." (n.b., Givens also has recipes for "Kohl-Rabi with Peanut Butter Sauce," "Buttered [boiled] Kohl-Rabi" and the more-delicious sounding "Kohl-Rabi with Cheese Sauce.")
Younger kohlrabi are more tender, while older kohlrabi tend to be woodier. You can differentiate between young and old primarily by size -- younger kohlrabi are smaller, usually between 2-3 inches in diameter. Kohlrabi should be spherical in shape; stay away from kohlrabi that are tapered, as they also tend to be woodier.
Kohlrabi bulbs will keep in your refrigerator's veggie drawer for several weeks. (I know this because I just cooked one that had been in the fridge for four weeks!) Note that the bulbs tend to become woodier the longer you store them. Remove the leaves before storing. If your kohlrabi have the leaves attached when you buy them, wrap the leaves in damp paper towels and store no longer than 2-3 days, as they lack the staying power of the bulb.
The biggest barrier to frequent kohlrabi consumption is peeling the pesky bulb. The little knobbly bits (where the leaves were attached) make using a vegetable peeler virtually impossible. Unless you are lucky to find a specimen whose skin peels off like a tangerine (I personally have never come across such a kohlrabi -- perhaps the kohlrabi of yesteryear were better?) you'll have to break out your finest paring knife to get the skin off. Larger kohlrabi will have a woody interior beyond the skin that will need to be pared away, too (you'll notice the change in texture as you pare). Trim off the stem end first, and then pare the skin and any woody interior parts away. Depending on the shape your recipe calls for, you may find that quartering your cabbage-turnip first will help the peeling process. The smallest kohlrabi may have skin tender enough that peeling is not necessary.
A versatile veggie, both the bulb and the leaves are edible. The bulb can be quartered and roasted like potatoes (toss with olive oil and salt and pepper first), pureed (especially nice mixed with potatoes), gratinéed with cheese, steamed, grilled or simply thinly sliced raw and tossed with olive oil, lemon juice, and salt and pepper. Kohlrabi also makes a delicious slaw, grated or cut into thin matchsticks. Cook kohlrabi leaves like you would other leafy greens, by either boiling for a few minutes in salted water, or by sautéing with olive oil and garlic until tender. The leaves can be eaten raw, tossed into a salad and are also delicious thrown into a stir-fry.
Kohlrabi is a great candidate for preservation. It can be fermented like sauerruben(sauerkraut made with turnips) or pickled. It even freezes well: blanch peeled and sliced kohlrabi for 2-3 minutes, then drop in an ice-water bath to shock, pat dry and freeze.
Adapted from The Farmer John Cookbook
I make these pancakes with my son, who has become a huge kohlrabi fan. He pronounces the name of the veggie like a sportscaster announcing a goal: "koooooohlraaaabi!" This recipe is good for kohlrabi novices and experts alike. I like my pancakes with a dollop of sour cream (orcrème fraîche) or applesauce.
4 small purple or green kohlrabi, peeled and trimmed of woody bits (see "Pro Tip" above)
1 small onion, very finely chopped or grated on the large holes of a box grater
1 small green chili, ribs and seeds removed, finely chopped or 1⁄4 teaspoon dried red pepper flakes (optional)
1 egg, lightly beaten
1⁄4 cup (or more) all-purpose flour
1⁄2 teaspoon ground coriander
1 tablespoon butter
2 tablespoons extra virgin olive oil
Salt and freshly ground pepper
1. Grate the peeled and trimmed kohlrabi on the large holes of a box grater. Wrap the grated kohlrabi in a clean dishtowel and squeeze until most of the excess moisture has been removed.
2. In a medium bowl, mix the shredded kohlrabi, chopped or grated onion, optional chilies or chili flakes, beaten egg, flour, coriander and salt and pepper to taste. Mix until just combined. Add additional flour by the teaspoon if batter seems too wet (mixture should be somewhat firm).
3. In a large, heavy frying pan, heat the extra virgin olive oil and the butter over medium-high heat until the butter stops foaming. Add ladlefuls of the pancake batter (about 1⁄3 of a cup at a time) to the pan, gently pressing down on the cakes with the back of a spatula. Cook kohlrabi pancakes until crispy and golden brown on each side.
4. Drain on paper towels and serve with sour cream, crème fraîche, yogurt or applesauce.
Note: The original recipe includes 1⁄2 teaspoon of ground ginger, which you might like to try in place of the coriander. Chopped cilantro or parsley would also be a nice addition.
Makes 4 generously sized pancakes.
A whole bunch of other useful kohlrabi recipes are posted here.
(*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 June 2012.