Barley (Hordeum vulgare) is an annual cereal grain, which serves as a major animal feed crop, with smaller amounts used for malting and in health food. It is a member of the grass family Poaceae. In 2005, barley ranked fourth in quantity produced and in area of cultivation of cereal crops in the world (560,000 km²). The domesticated form (H. vulgare) is descended from wild barley (H. spontaneum). Both forms are diploid (2n=14 chromosomes). As wild barley is interfertile with domesticated barley, the two forms are often treated as one species, Hordeum vulgare, divided into subspecies spontaneum (wild) and subspecies vulgare (domesticated). The main difference between the two forms is the brittle rachis of the former, which enables seed dispersal in the wild.

Crop history

Wild barley comes from Epi-Paleolithic sites in the Levant, beginning in the Natufian. The earliest domesticated barley occurs at Aceramic Neolithic sites in the Near East such as the (PPN B) layers of Tell Abu Hureyra in Syria. Barley was one of the first crops domesticated in the Near East, at the same time as einkorn and emmer wheat. pt;margin:2em 0 1em 1em;" |- |+ Barley in Egyptian hieroglyphs |jt barley determinative/ideogram |M34 |- |jt (common) spelling |i-t-U9:M33 |- |šma determinative/ideogram |U9 |} Barley was alongside emmer wheat, a staple cereal of ancient Egypt, where it was used to make bread and beer; together, these were a complete diet. The general name for barley is jt (hypothetically pronounced "eat"); šma (hypothetically pronounced "SHE-ma") refers to Upper Egyptian barley and is a symbol of Upper Egypt. According to Deuteronomy 8:8, barley is one of the "Seven Species" of crops that characterize the fertility of the Promised Land of Canaan, and barley has a prominent role in the Israelite sacrifices described in the Pentateuch (see e.g. Numbers 5:15). A religious importance extended into the Middle Ages in Europe, and saw barley's use in justice, via alphitomancy and the corsned.

In ancient Greece, the ritual significance of barley possibly dates back to the earliest stages of the Eleusinian Mysteries. The preparatory kykeon or mixed drink of the initiates, prepared from barley and herbs, was referred to in the Homeric hymn to Demeter, who was also called "Barley-mother".

The practice was to dry the barley groats and roast them before preparing the porridge, according to Pliny the Elder's Natural History (xviii.72). This produces malt that soon ferments and becomes slightly alcoholic.

Tibetan barley has been the only major staple food in Tibet for centuries. It is made into a flour product called tsampa.