An ancient grain that has been cultivated for centuries. The individual pieces of long-grain rice are an average of 7 mm in length. Long-grain rice is also identifiable after cooking as the grains remain separate, rather than clumped. Rice is commercially classified by size: long, medium or short grain. Long-grain rice is 4-5 times its width and is available in white and brown varieties, which are light, dry grains that separate easily when cooked.  The grains stay separate and fluffy after cooking, so this is the best choice if you want to serve rice as a side dish, or as a bed for sauces. Bran is the layer of long-grain rice that lays beneath the hull or shell of each grain of rice. Brown long-grain rice has the bran still intact, while there is no bran remaining on white long-grain rice. There are a number of sub-varieties of long-grain rice, such as Basmati which has a nutty taste, as well as American long grain which has a relatively bland flavor. There are between 7,000 and 10,000 rice varieties in the world which can be sub-divided into three types according to their various shapes: long grain, medium grain and short grain rice. The U.S. is known primarily for exporting long grain rice, but it also cultivates the other rice types.