Sorghum is a grain produced by cereal plants of the species Sorghum vulgare and S. bicolor, a drought-tolerant staple across Africa and Asia. The seeds may be dark brown or red, or white to yellow; dark seeds carry a high content of tannins, which decrease palatability and protein digestibility, so white and yellow seeds are preferred for food applications. Food uses include porridge, bread, and beer, and the grain is also a source of starch and syrups. Naturally gluten-free, sorghum is valuable for coeliac-friendly products, and its hardiness in hot, dry climates makes it a food-security crop where maize and wheat struggle.