Rhubarb is a vegetable, although it is commonly prepared as if it were a fruit. Only the stalks are edible as the leaves of rhubarb are poisonous due to high levels of oxalic acid. Rhubarb is grown widely, especially in heated greenhouses, so that it is available throughout the year. “Hothouse rhubarb” is usually brighter red, tender, and sweeter tasting than outdoor rhubarb. Outdoor rhubarb can be harvested as early as mid-to-late spring and throughout the summer. Rhubarb stalks are a good source of vitamins A, K, C, potassium, calcium, fiber, and manganese.
Buying & Storing
When buying rhubarb, look for stalks that are firm with a glossy sheen. Try to avoid stalks that are wider than 1-inch, as this might mean the rhubarb has become too woody or stringy. Also, rhubarb should not be consumed if it was harvested after a severe frost as the oxalic acid levels in the stem can increase to dangerous levels. Never purchase rhubarb that has soft, limp stalks or shows any signs of black, shriveled leaves. Typically the leaves of rhubarb have been removed before being sold so people don’t accidentally eat them, but if there is any evidence of blackened leaves near the top of the stalk, it is always better to be safe and avoid those stalks.
Store rhubarb in the refrigerator wrapped in a damp towel or in a plastic bag (or both) for up to 1-3 weeks. Stems will soften and shrivel as they dehydrate, similar to celery, so change the paper towels or re-dampen as needed if they dry out.
Freeze rhubarb for long-term storage, either raw or cooked. Wash, chop and place in boiling water for approximately 1 minute, and then immediately place in cold/ice water to stop the cooking. Once the rhubarb has cooled completely, place in airtight containers or freezer bags and freeze.
Preparation – cut and discard the leaves, if they haven’t already been removed. Cut off any woody parts from the base of the stem. Typically, the woody section on a stalk of rhubarb will be paler in color, if not white, and can easily be removed with a knife. A general rule of thumb with rhubarb is to remove the bottom inch of each stalk, and then more if a stalk still has a white section present. If the rhubarb is older and the stalks are wider than 1-inch, it may need to be peeled in order to remove the tough outer layers. Use a vegetable peeler to remove the stringy outside layer.
While rhubarb is typically cooked, young tender stems may be eaten raw. The tartness balances nicely with sweet dishes—slice or dice raw rhubarb and add it to ice cream sundaes, hot or cold cereal, or use as a garnish on a dessert. For savory tastes, add raw rhubarb to salads or as a garnish for savory soups.
Soup – while rhubarb is delicious as a garnish on soup (typically a cold soup), it can also be used in soups. Add small rhubarb slices toward the end of the cooking time to retain texture while adding wonderful flavor.
Roast – rhubarb can be roasted similarly to roasted carrots. Slice or chop rhubarb, sweeten with a little brown sugar or honey, toss in a baking dish and bake in the oven at 375°F for 30 minutes. Add fresh rosemary for a savory twist.
Sauce – rhubarb sauce is one of the most common uses of the vegetable. It can be left as a sauce or reduced further and canned as a jam or chutney. For a basic sauce, chop stems into 1-inch chunks and cook in a small amount of water with the sweetener of your choice (to taste) until the stalks begin to break down. When the fibrous stalks become stringy and mushy, it is done. Use the sauce to pour over cake or ice cream, or freeze or can to enjoy later.
Beverage – sliced raw rhubarb can be added to water in order to flavor the water. It can also be blended for a fresh take on a margarita or bloody mary. It can also be used to make fruit wine or a vodka liqueur.