Of the approximately 8,000 species in the grass family, only a handful play a significant role in the human diet. Aside from bamboo and sugar cane, these are the cereals. While their grains are very similar in structure and composition, the differences have made for widely divergent culinary histories.
The major Eurasian cereals—wheat, barley, rye, and oats—originally grew wild in extensive stands on the temperate high plains of the Near East. Groups of early humans could harvest enough wheat and barley from these wild fields in a few weeks to sustain themselves for a year. Some 12,000 to 14,000 years ago, the first agriculturalists began to plant and tend wheat and barley seeds selected for their size and the ease with which they could be harvested and used; and farmers gradually spread these crops throughout western and central Asia, Europe, and north Africa. Each cereal had its advantages. Barley was especially hardy, while rye and oats were able to adapt to wet, cold climates, and wheat produced a uniquely elastic paste that could be filled with tiny bubbles and baked into tender raised breads. Around the same time, the inhabitants of tropical and semitropical Asia domesticated rice, with its special ability to grow in wet, hot growing conditions. Somewhat later in warm central and South America arose maize, or corn, whose plants and kernels dwarf those of the other cereals.