Rice

Rice is an annual grass growing about one metre tall, with narrow leaves and drooping panicles of small flowers that develop into the grains. Each grain is enclosed in a hull; removing it yields brown rice, which still carries its bran and germ, and further milling removes these to give white rice. Varieties are grouped broadly as short-, medium- and long-grain, and as aromatic types such as basmati and jasmine. Cooked grains range from sticky and tender to dry and separate, depending on their starch composition. Most rice is grown in flooded fields called paddies, though upland rice is grown without standing water.

Cultivated Asian rice was domesticated from wild rice relatives in the Yangtze River valley of China roughly 9,000 years ago, according to archaeological and genetic studies. Two main subspecies, japonica and indica, arose through domestication and later crossing, with a separate line leading to aus and aromatic groups in South Asia. From these centres rice spread across Asia, then westward to the Middle East and Europe, and was carried to the Americas from the sixteenth century onward. Today China, India, Bangladesh, Indonesia and Vietnam are among the largest producers, and rice is grown on every continent except Antarctica.

Rice is among the oldest crops in human history and has shaped the landscapes, calendars, languages and religious ceremonies of many Asian societies. Terraced paddies in places such as the Philippines and China represent centuries of cooperative engineering. Rice reached Persia and the Mediterranean through ancient trade, and was grown in southern Europe, notably Spain and Italy, by the Middle Ages. Enslaved West Africans with knowledge of rice cultivation contributed greatly to the rice industry of the coastal southeastern United States.

In the twentieth century the Green Revolution introduced semi-dwarf, high-yielding varieties that dramatically raised production through breeding programmes in Asia. Rice remains a symbol of sustenance in many cultures: it is thrown at weddings in some traditions, offered at temples, and the word for cooked rice doubles as the word for a meal in several languages. Current research focuses on drought-, flood- and salt-tolerant varieties and on reducing the methane emissions of flooded paddies.

Rice is boiled, steamed or cooked by the absorption method as a side dish or base for curries, stews and stir-fries. It is the basis of pilaf, risotto, paella, biryani, congee, sushi and countless rice-and-bean dishes. Rice is milled into flour for noodles, wrappers, cakes and gluten-free baking, and fermented into vinegar, sake and other drinks. Puffed, flaked and ground forms appear in cereals, snacks and porridges. Rice bran is pressed for oil, and rice hulls are used as fuel and packaging. Cooked grains keep well when cooled quickly and refrigerated.

Rice is mostly starch and is a primary energy source in many diets. Brown rice retains bran and germ, so it provides more fibre, magnesium, manganese and B vitamins than polished white rice, which is often enriched with iron and folic acid in some countries. Whole grain intake in general is associated with healthy eating patterns, although rice is only one of many grain choices. White rice has a higher glycaemic index than brown rice in many comparisons, and varieties differ. Rice is naturally gluten-free, making it a common staple for people avoiding gluten.