Buckwheat is actually not a cereal grain, but instead is an herb from the buckwheat family. It is more closely related to rhubarb than to grass. Buckwheat got its name from the Scots who combined the words "boc" (meaning beech) and "whoet" (meaning wheat). The Scots gave buckwheat this name because they thought it resembled a beechnut and used its grain much in the same way as wheat. Buckwheat is thought to have first been grown in China more than a thousand years ago. It was brought to Europe during the Middle Ages and made its way to the Americas with the early pilgrims.
There are three species of buckwheat; Fagopryum esculentum, F. tartaricum, and F. cymosum. The latter is the most common species, accounting for about 90% of all buckwheat grown worldwide. The buckwheat plant grows to between two and five feet tall and has characteristic heart-shaped leaves. The plant produces gray or black triangular seeds that are surrounded by a tough outer hull. Buckwheat is predominately grown in Russia and China, but other producers include Japan, Canada, the United States, and Australia. Roughly 5 million acres of land worldwide are devoted to buckwheat crops.
Buckwheat is sold in several different forms. It can be purchased whole with the hull attached to the seed. These whole seeds can be grown to make nutritional sprouts. When the hulls have been removed from the seeds they are called "buckwheat groats". The outer hull is generally removed by grinding the seeds and the seeds themselves are often ground into smaller pieces. Groats are cooked by boiling and are mainly used in side dishes such as a pilaf or used to make a coarse breakfast cereal common in Eastern Europe. They are somewhat bitter so chefs often cook the groats in a bit of oil before boiling to reduce the bitterness and bring out a nutty flavor. Groats that have been roasted in oil are called "kasha", the Russian word for porridge. Kasha comes whole or crushed to a varying degree of fineness. They are used like groats, but give a nuttier flavor to dishes. Groats are also often finely ground to make "buckwheat grits," which are used in breakfast cereal.
Buckwheat seeds are also ground into a light and delicate-tasting flour. This flour is generally combined with wheat flour to make bread, pancakes, and muffins. Buckwheat flour is also mixed with wheat flour to make hearty soba noodles commonly used in Asian dishes (soba is the Japanese word for buckwheat). Buckwheat flour gives its baked products a nice deep brown color and added nutrition. Buckwheat flour contains high levels of zinc, copper, manganese, and potassium.
The buckwheat plant has other uses besides its seeds. The remaining plant is often used as livestock feed. Buckwheat leaves also are harvested because they contain a flavonoid called rutin. This compound is used to treat high blood pressure and helps to strengthen blood vessels. Additionally, bees produce a dark, strong flavored honey from buckwheat flowers. Even the hard buckwheat hulls are used. They are lightweight and durable and therefore are often used as a natural filling in pillows.
Pignut notes that you can also use buckwheat flour as a great facial scrub
However, Excalibre says: "i must protest the suggestion to use buckwheat as a facial scrub. foods in general are terrible things to use on your skin; the starches tend to collect somewhat in your pores, encouraging bacterial growth."
sneff informes me that buckwheat flour is also used for special Russian pancakes called blini
http://www.foodsubs.com/GrainBuckwheat.html
http://www.hort.purdue.edu/newcrop/proceedings1993/V2-251.html
http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex103