A dish that originated in northern Italy, risotto turns a medium-grained rice called Arborio into a creamy dish balanced by a pleasantly firm "tooth" (al dente). A wide variety of other ingredients can be added to risotto, such as cheese, vegetables, and meat. Risotto ai funghi, for example, contains mushrooms while risotto alla pilota combines sausage, pork, and Parmesan cheese with the creamy rice.
Arborio Rice Characteristics
Rice generally gets organized into three groups: long-, medium-, and short-grain based on the length and width when cooked. Short-grain rice plumps to an almost spherical shape, while long-grain rice looks a bit like a grain of wheat; medium falls somewhere in between. Arborio does plump as it cooks, making it appear shorter, but its width-to-length ratio qualifies it as a medium-grain variety.
Whether long- or short-grained, all types of rice contain starches called amylose and amylopectin. These starches define the texture of the rice as it cooks. Amylose does not break down into a gelatin-like consistency, while amylopectin does (pectin is the ingredient that makes jelly gel), resulting in the characteristic creaminess of risotto and stickiness of some Asian rices. Short-grain rices contain more amylopectin and less amylose than long-grain rices.
Arborio's high amylose content helps give risotto its characteristic creaminess. Arborio also contains a structural deformity called "chalk" (not the kind used on a blackboard), that preserves a firm center even as the rice cooks and the surrounding starch breaks away. Chalk gives Arborio rice that little bit of chewiness that the Italians refer to as "al dente."
Arborio Rice Substitutions
Any rice variety (or grain) you substitute for Arborio needs the same basic qualities for a successful risotto. They must be high in amylose but able to maintain a little bit of chewiness even after being cooked for a long time, since risotto requires a slower cooking process with repeated additions of hot stock.
Two other Italian rice varieties substitute well for Arborio and in some cases, may work even better: Carnaroli rice, another medium-grained so-called superfino variety with an even higher starch content than Arborio, is a classic—if lesser known—choice for risotto in parts of northern Italy. A harder-to-find option is Vialone Nano, a semifino medium-grain rice grown in the Veneto region. More rarely, Italians may use Balo, Calriso, or Maratelli rice.
But if you don't happen to have Arborio rice on your shelf, and you aren't in Italy (or eager to spend a great deal of money on pricey imports), don't feel restricted to Italian rice varieties. The key to successful risotto is a short- or medium-grain rice with a firm texture and high-starch content. White sushi rice works nicely, as does Thai jasmine rice.
Adventurous cooks can go beyond rice to experiment with starchy, rice-shaped grains, such as pearled barley or farro.
Bulgur wheat, barley, and couscous can also make a risotto-like base for a meal.