When is a root vegetable not a root vegetable? When it's a small bulbous member of the cabbage family called kohlrabi, that's when. For all intents and purposes, kohlrabi appears to be a root vegetable in the same company as turnips, radishes and rutabagas. However, the bulbous shape is caused by a swelling of the plant's stem near the ground. In that sense, it is more of a tightly packed version of its cousin, cabbage. In fact, the name is derived from two German words: kohl meaning cabbage and rabi meaning turnip. It is not unusual to hear the term "turnip cabbage" to describe this vegetable.
Despite its connections to cabbage and turnips, steamed or boiled kohlrabi is said to taste more like broccoli or Brussels sprouts. Indeed, it is in the same general category, the Brassica oleracea Gongylodes group, as the broccoli it resembles in flavor. It can also be used in lieu of cabbage in many of the sausage and cabbage dishes favored in German cooking.
A raw kohlrabi can also be eaten like an apple, although it contains far less sugar. Some people find the taste to be an acquired one, but many people who were raised in largely German communities in the Midwest grew up eating kohlrabi whenever it was in season. One town in Illinois even held annual festivals in honor of the vegetable, but such enthusiasm has waned somewhat in recent years.
There are certain things to consider when shopping for kohlrabi. It is not always available in the produce section of many grocery stores. The vegetable is very seasonal, and low consumer demand often keeps it off the truck for long-distance deliveries. The best kohlrabi is usually found in farmers' markets or locally owned produce stores.
Ideally, a kohlrabi bulb should be about the size of an apple or smaller, approximate 3 inches (7.62 cm) in diameter. Anything larger could have noticeably less flavor or woody sections. Kohlrabi may look like a root vegetable, but it should be displayed separately from true root vegetables such as turnips or rutabagas. The plants have a distinctive leafy stalk protruding from the top of the swollen stem. This stem is usually removed before chopping the actual bulb for steaming or boiling in salted water.