In a 100-gram serving providing 343 calories dry and 92 calories cooked, buckwheat is a rich source (20% or more of the Daily Value, DV) of protein, dietary fibre, four B vitamins and several dietary minerals, with content especially high (47 to 65% DV) in niacin, magnesium, manganese and phosphorus (table). Buckwheat is 72% carbohydrates, including 10% dietary fibre, 3% fat and 13% protein (table).
As buckwheat contains no gluten, it may be eaten by people with gluten-related disorders, such as celiac disease, non-celiac gluten sensitivity or dermatitis herpetiformis.Nevertheless, buckwheat may have gluten contamination.
The fruit is an achene, similar to sunflower seed, with a single seed inside a hard outer hull. The starchy endosperm is white and makes up most or all of buckwheat flour. The seed coat is green or tan, which darkens buckwheat flour. The hull is dark brown or black, and some may be included in buckwheat flour as dark specks. The dark flour is known as blé noir (black wheat) in French, along with the name sarrasin (saracen).
Buckwheat noodles have been eaten by people from Tibet and northern China for centuries, as wheat cannot be grown in the mountain regions. A special press made of wood is used to press the dough into hot boiling water when making buckwheat noodles. Old presses found in Tibet and Shanxi share the same basic design features. The Japanese and Koreans may have learned the making of buckwheat noodles from them.
In India, on Hindu fasting days (Navaratri, Ekadashi, Janmashtami, Maha Shivaratri, etc.), fasting people in northern states of India eat foods made of buckwheat flour. Eating cereals such as wheat or rice is prohibited during such fasting days. However, since buckwheat is not a cereal, it is considered acceptable for consumption during Hindu fasting days. While strict Hindus do not even drink water during their fast (observing Nirjal Upwas), others just give up cereals and salt and take a meal prepared from non-cereal ingredients such as buckwheat (kuttu). The preparation of buckwheat flour varies across India. Well-known buckwheat flour recipes are kuttu ki puri (buckwheat pancakes) and kuttu pakoras (potato slices dipped in buckwheat flour and deep-fried in oil). In most of the northern and western states, buckwheat flour is called kuttu ka atta.
Buckwheat noodles play a major role in the cuisines of Japan (soba), Korea (naengmyeon, makguksu and memil guksu), buckwheat fresh pasta (pasta di grano saraceno) in Apulia region of Southern Italy and the Valtellina region of Northern Italy (pizzoccheri). Soba noodles are the subject of deep cultural importance in Japan. In Korea, guksu (noodles) were widely made from buckwheat before it was replaced by wheat. The difficulty of making noodles from flour with no gluten has resulted in a traditional art developed around their manufacture by hand.
Buckwheat groats are commonly used in western Asia and eastern Europe. The porridge was common, and is often considered the definitive peasant dish. It is made from roasted groats that are cooked with broth to a texture similar to rice or bulgur. The dish was brought to America by Ukrainian, Russian, and Polish immigrants who called it kasha, and they mixed it with pasta or used it as a filling for cabbage rolls, knishes, and blintzes; buckwheat prepared in this fashion is thus most commonly called kasha in America. Groats were the most widely used form of buckwheat worldwide during the 20th century, eaten primarily in Estonia, Russia, Ukraine, Belarus, and Poland, called grechka in Ukrainian or Russian. The groats can also be sprouted and then eaten raw or cooked.
Buckwheat pancakes, sometimes raised with yeast, are eaten in several countries. They are known as buckwheat blinis in Russia, galettes in France (savoury crêpes made with buckwheat flour, water, and eggs are associated with Lower Brittany, whilst savoury galettes made without eggs are from Upper Brittany), ployes in Acadia, and boûketes (which are named after the buckwheat plant) in the Wallonia region of Belgium. Similar pancakes were a common food in American pioneer days. They are light and foamy. The buckwheat flour gives them an earthy, mildly mushroom-like taste. In Ukraine, yeast rolls called hrechanyky are made from buckwheat. Buckwheat flour is also used to make Nepali dishes such as dhedo and kachhyamba.
Farina made from groats are used for breakfast food, porridge, and thickening materials in soups, gravies, and dressings. In Korea, buckwheat starch is used to make a jelly called memilmuk. It is also used with wheat, pasta and bread products in Apulia Italy, maize (polenta taragna in northern Italy) and rice.
Buckwheat is a good honey plant, producing a dark, strong monofloral honey.