Buckwheat is not a grain, in spite of its name. Grains belong to the grass family, whereas buckwheat varieties belong to a family of herbs of Asian origin called Fagopyrum. However, because buckwheat has grain-like properties, it is often referred to as a pseudo-cereal. The buckwheat plant has small, off-white, triangular, edible, fruits called “achenes.” These are high in protein, and, like barley kernels, are mostly made of starch. Also like barley, they have endosperms and aleurone layers, and contain the diastatic enzymes alpha-amylase and beta-amylase. See alpha amylase and amylases. When ground, buckwheat seeds can be used as a flour substitute. In a beer mash they can be used malted or unmalted as an adjunct. See adjunct. In the finished beer, they add a slightly nutty flavor.

The proportion of buckwheat in a mash may be as high as one-half, though experimental mashes with 100% buckwheat have been reported in brewing literature. However, because of the buckwheat’s relatively high protein content, a mash with buckwheat generally necessitates a grist-to-water ratio of 1:4 or thinner to avoid excessive mash viscosity, clumping, and low extract volumes. Buckwheat, unlike most cereal grains, is also gluten-free. See gluten-free beer. Individuals with celiac disease, who cannot drink most beers because of the presence of gluten, can usually tolerate beer made from buckwheat in conjunction with such gluten-free grains as sorghum and/or millet.