Rhubarb is a relative of buckwheat and has an earthy, sour flavor. Rhubarb thrives in cold climates and originated in Western China, Tibet, Mongolia, Siberia and neighboring areas. The traditional role was medicinal — the dried root was a popular remedy for a wide range of illnesses. Its primary function was to induce vomiting, although rhubarb is also a mild astringent. This medicinal role caused the price of the dried root to rise. In 1542, rhubarb sold for ten times the price of cinnamon in France and in 1657 rhubarb sold for over twice the price of opium in England (Schneider, 2001). Beginning in the eighteenth century, rhubarb began to be consumed in foods, primarily drinks and meat stews.
Botanically speaking, rhubarb is considered a vegetable, but it's most often treated as a fruit — though it's rarely eaten raw. Just like fresh cranberries, rhubarb is almost unbearably tart on its own and needs the sweetness of sugar, honey, or fruit juice added to it to balance out the acidity. Rhubarb's nickname is the "pie plant" because that is the primary use for this vegetable.
Rhubarb was introduced to the United States at the end of the eighteenth century. Today most rhubarb is frozen for commercial and institutional use; only about a quarter of the crop is sold fresh.
Hothouse, or strawberry, rhubarb appears in markets as early as January and continues to be stocked through April. Field-grown, or cherry, rhubarb begins to arrive in markets in March and can continue to arrive through the summer (depending on the area where it is grown). Spring stalks are the juiciest and most-tender.
Fresh stalks are flat, not curled or limp. When stalks that have been pulled-not cut-from the field are available; choose them. Pulled stalks dry out less rapidly. Size is no indicator of tenderness. Deep red stalks are sweeter and richer.
Wrap rhubarb in plastic wrap and store it in the coldest part of the refrigerator for up to one week. Cooked and raw rhubarb both freeze well.
Cut off and discard the leaves (see warning below). Rinse and trim from base and tip. You may peel or cut with the skin intact. Remember to cook only in non-aluminum pots due to the acidic nature of rhubarb.
Never eat rhubarb leaves, cooked or raw. Eating the leaves can be poisonous because they contain oxalates. This toxin, plus another unknown toxin also found in the leaves, has been reported to cause poisoning when large quantities of raw or cooked leaves are ingested.
Rhubarb stalks are also rich in vitamin K, important to note for people taking bloodthinners.