Barley and their hybrids and derivatives, barley contains gluten, which makes it an unsuitable grain for consumption by people with gluten-related disorders, such as celiac disease, non-celiac gluten sensitivity and wheat allergy sufferers, among others. Nevertheless, some wheat allergy patients can tolerate barley or rye. Barley is a key ingredient in beer and whisky production. Two-row barley is traditionally used in German and English beers. Six-row barley was traditionally used in US beers, but both varieties are in common usage now. Distilled from green beer, whiskey has been made primarily from barley in Ireland and Scotland, while other countries have used
Wheat gluten (food) among adherents of Buddhism. The oldest reference to wheat gluten appears in the "Qimin Yaoshu", a Chinese agricultural encyclopedia written by Jia Sixie in 535. The encyclopedia mentions noodles prepared from wheat gluten called "bo duo". Wheat gluten was known as "mian jin" by the Song dynasty (960–1279). Wheat gluten arrived in the West by the 18th century. "De Frumento", an Italian treatise on wheat from 1745, describes the process of washing wheat flour dough in order to extract the gluten. John Imison wrote an English-language definition of wheat gluten in his "Elements of Science and Art" published in 1803.