Risotto recipes always call for a short-grained rice like Arborio. Since sushi rice is also short-grained, will it also work?
Whether the grains of a variety of rice will cook up sticky or separate is largely determined by the relative amounts of two starches: amylose and amylopectin. Varieties of rice with low levels of amylose and high levels of amylopectin cook up sticky, while those with high levels of amylose remain firm and produce more separate grains. Arborio, carnaroli, and sushi rice all have a greater proportion of amylopectin. The relative dryness of cooked sushi rice in contrast with the sauciness of risotto has to do with the vastly different liquid to rice proportions that recipes for each require (about equal parts for sushi rice and five or six times as much liquid as rice for risotto). So what would happen if we cooked sushi rice in a lot of liquid as we do for risotto? We headed to the kitchen to find out.
Following a test kitchen recipe for risotto, we added wine and broth in increments, and we noticed that the sushi rice was soaking up the liquid a little faster than risotto made with Arborio rice. When all was said and done, the two batches looked similarly creamy. When tasted side by side, the risotto made with sushi rice tasted good, but the grains lacked the firm center of risotto made with Arborio rice. It turns out that Arborio rice has a unique characteristic called chalk that causes the starch structures in the centers of the grains to deform in such a way that they remain firm after cooking. Because the sushi rice “risotto” lacked a distinguishing feature of risotto, we deemed the resulting dish tasty but not risotto.
THE BOTTOM LINE: Using sushi rice in a risotto recipe will yield a creamy, tasty dish, but the grains will lack the slight al dente bite that defines real risotto.