Non-sticky (nonglutinous) rice; sticky (glutinous) rice

The normal rice used as the staple food of the Japanese is called  uruchi-mai (nonglutinous or non-sticky rice) . The kind of rice that becomes sticky after being steamed or boiled and has been used in Japan for sweets or mochi rice cakes since ancient times is called  mochi-mai (glutinous or sticky rice) .

Rice starch has two components: amylose consisting of unbranched single glucose chains and amylopectin consisting of branched glucose chains. The stickiness of mochi-mai comes from amylopectin. The starch of Japanese type uruchi-mai contains 17%-21% amylose and the rest is amylopectin, whereas the starch of sticky rice is almost 100% amylopectin.

Uruchi-mai becomes semi-transparent when it is dried after full maturity but mochi-mai turns to opaque milky white. It is ordinary uruchi-mai that is generally used for sake making: however, mochi rice may be used in fourth stage mashing (yo-dan).