Water Chestnuts, European water chestnuts, water caltrops, Jesuit nut, Singhara-nut
châtaigne d’eau (French), Wassernufs (German), castagna d’acqua (Italian), krajab (Thai), bi qi (Chinese), hishinomi (Japanese)
(Trapa sp. – Family Onagraceae)
Water chestnuts is a name applied to three water plants. These strangely-shaped fruits each enclose a large white kernel that resembles a chestnut in size, flavour, and texture. The true water chestnut best known in Europe is Trapa natans and often called a “caltrop,” which is a military device consisting of four metal spikes arranged so that no matter which way it falls, one spike is always pointing upward. Caltrops are still used in guerilla warfare to burst car tires. This particular water chestnut also has four spikes, with one pair larger than the other. In China, Korea, and Japan, there is a different species, T. bicornis, that has two large curved “horns.”
This nut has been an important food in China since ancient times and usually eaten boiled or roasted. Because of its starchiness, it was counted as a grain rather than a nut and generally consumed in the form of a flour. It is advised that they be well cooked because they can harbour toxins and parasites. They are very difficult to handle, according to Elizabeth Schneider, who used “boiling, steaming, nutcracker, cleaver, hammer, and lobster pick” to extract finally a bit of the starchy matter lodged within. Hardly worth the effort. The singhara nut, T. bispinosa, is an important food in Kashmire. The name is Bengali and the plant is cultivated in lakes or along river banks, and can be found over a wide area from Africa to Japan.
– Chinese Water chestnut, waterchestnut, waternut
ma tai (Chinese)
(Eleocharis tuberosa or dulcis – Family Cyperaceae)
The Chinese water chestnut is a member of the Sedge family and not related to the true water chestnut of the Evening Primrose family. The Sedge family usually contains such useful, but inedible, plants as rushes, sedges, and cotton grasses. The pseudobulbs (corms) of the tiger nut and Chinese water chestnut are harvested as a vegetable from plants cultivated in still water. These corms mature slowly and are painstakingly harvested by hand. The marsh plant is native to West Africa, Madagascar, India, the Pacific Islands, and all of East Asia. In Chinese markets, these water chestnuts are sold unpeeled and with soil still clinging to them. This keeps the white flesh under the skin fresher longer, which is easily peeled after washing.
As the name suggests, the Chinese water chestnut is of great culinary importance in China. The dark brown or black tubers are located on the roots and are prized for their sweetish, firm, white flesh in both savory and sweet dishes. In Canton, chopped water chestnuts are used as a filling for dim sum, a steamed dumpling enjoyed as a snack. In European cuisine, they are used as a piquant hors d’oeuvre. Most people are acquainted with the canned form that offers a crunch, but little else. The solid flesh of the fresh ones is dramatically different from the canned, and once the scruffy coat is removed, offers sweet, juicy tidbits that taste like apples, sunchokes, and sugarcane. During cooking, the corms have an aroma of sweet corn. The Chinese water chestnuts are a popular ingredient in Southeast Asian desserts. Flour is made from the peeled, dried chestnut and used as a thickening agent.