Worldwide there are more than 120,000 different varieties of rice, though only a small number offer the quality acceptable for commercial growth in the United States. These varieties can be divided into long, medium and short grain rice. An increasing number of sweet, aromatic and arborio rice varieties are also produced in the U.S. The principal differences in these varieties are their cooking characteristics, texture and some subtle flavor variation. From a nutritional standpoint they are equal and can be used interchangeably, depending on the recipe.
Long Grain - Long grain rice has a long, slender kernel three to four times longer than its width. Due to its starch composition, cooked grains are more separate, light and fluffy.
Medium Grain - Medium grain rice, when compared to long grain rice, has a shorter, wider kernel that is two to three times longer than its width. Cooked grains are more moist and tender than long grain, and have a greater tendency to cling together.
Short Grain - Short grain rice has a short, plump, almost round kernel. Cooked grains are soft and cling together, yet remain separate and are somewhat chewy, with a slight springiness to the bite.