More than two thousand varieties of rice are grown throughout the world. The International Rice Research Institute (IRRI) in the Philippines holds more than 83,000 varieties in its gene bank. The differences are related to morphology of the plants and grains, resistance to falling, precocity, ramification, productivity, as well as resistance and tolerance of biotic factors (weeds, diseases and insects) and non-biotic factors (cold, drought, soil acidity, lack of mineral components, etc).
* The market of high-quality rice with a low percentage of broken grains (less than 10%) is dominated by Thailand, Vietnam and the United States growers whose production essentially meets the market demands of developed countries.
* The market of lower-quality rice (more than 10% of broken kernels) is dominated by exporters from Asia region (Thailand, Vietnam and India) who mainly meet the market demands of developing countries in Africa, Latin America and Asia.
- Medium-quality rice: 15-20% broken
- Low-quality rice: 25-35% broken up to 100% broken.
* The market of high-quality rice with a low percentage of broken grains (less than 10%) is dominated by Thailand, Vietnam and the United States growers whose production essentially meets the market demands of developed countries.
* The market of lower-quality rice (more than 10% of broken kernels) is dominated by exporters from Asia region (Thailand, Vietnam and India) who mainly meet the market demands of developing countries in Africa, Latin America and Asia.
- Medium-quality rice: 15-20% broken
- Low-quality rice: 25-35% broken up to 100% broken.
Any irregularity (yellow or chalky kernels and foreign matter) reduces the rice quality grade.
- Long grain rice kernels are 3 times longer than they are wide (more than 6 mm). When cooked, this grain is light and separates easily. There are also glutinous long grain rices in Laos and Thailand.
- Medium grain rice kernels are 2 or 3 times longer than wide (5 to 6 mm), being shorter and wider than the long grain.
- Short or round grain rice kernels look almost as long as wide (4 to 5 mm long and 2.5 mm wide).
• Long grain rice: Basmati from India and Pakistan, Jasmine White Rice from Thailand and Ferrini from Italy;
• Medium and short grain: Arborio, Carnaroli, Vialone, Nano
- Medium grain rice kernels are 2 or 3 times longer than wide (5 to 6 mm), being shorter and wider than the long grain.
- Short or round grain rice kernels look almost as long as wide (4 to 5 mm long and 2.5 mm wide).
• Long grain rice: Basmati from India and Pakistan, Jasmine White Rice from Thailand and Ferrini from Italy;
• Medium and short grain: Arborio, Carnaroli, Vialone, Nano
Brown rice (husked rice)Paddy from which only the external and non-edible husk has been removed. The bran layer remains, making it more nutritive than white rice. In Europe, this type of rice is often called "cargo rice" because of the way it is transported by sea. Frequently green kernels are found with the brown rice as grain maturation is not homogeneous. In addition, more than one variety may be planted in the same field. Separating the grains before or after harvesting is difficult and expensive. There are also green grains in the white rice, but they are less visible because of the more intensive husking process.
White rice
Milled and polished kernel which loses many of its nutrients when the outer layer (the husk and bran layer) is removed. It contains much less niacin, thiamin, magnesium, zinc, iron and fiber than the brown rice. In some countries, including the United States, white rice may be enriched with iron, niacine and thiamine so that it can reclaim part of its original nutritive value. White rice may be covered with magnesium silicate or with a mixture consisting of talc and glucose (also known as "talc-coated rice").
Red rice
Red rice has a red bran covering the kernel (Himalayan, Bhoutanais or Thai).
- Black rice: has a black thin bran covering a white grain. It comes from Bali, China or Thailand.
- Black rice: has a black thin bran covering a white grain. It comes from Bali, China or Thailand.
Others
• Arborio rice is a white and round grain, considered one of the finest rices because it can absorb a high quantity of liquid while cooking, without becoming soggy.
• Aromatic rice (naturally aromatized) has more flavor than the other varieties. The Basmati rice, cultivated in India and Pakistan, is the best known and most appreciated. It is indispensable in Hindu cooking, and has a light and dry texture and an aromatic taste. Jasmine rice grows in Northeast Thailand (Isarn region) and is also appreciated worldwide.
• Aromatic rice (naturally aromatized) has more flavor than the other varieties. The Basmati rice, cultivated in India and Pakistan, is the best known and most appreciated. It is indispensable in Hindu cooking, and has a light and dry texture and an aromatic taste. Jasmine rice grows in Northeast Thailand (Isarn region) and is also appreciated worldwide.