Kitchen Mysteries is a weekly exploration of oddities surrounding cooking and food. They could be recipes that fail when they shouldn't, conflicting advice from different sources, or just plain weirdness. If it happens in a kitchen, and you're not sure why, send a tweet to The Food Geek to find out what's happening.
Amy asks via Twitter:
Soaking is generally an optional step in rice cooking, but people are more insistent about it with basmati rice. What makes it so special? Well, it's a long-grained rice, but there are plenty of those that don't require soaking, so that's probably not it. The other key to basmati rice is that it's flavored, which is much more important.
According to June Chua, basmati rice is heavy in the flavor compound 2-Acetyl-1-pyrroline compared with other types of rice, and 2-Acetyl-1-pyrroline is a bready sort of flavor. The thing about flavor compounds is that they are often susceptible to heat. Spices that are left too close to the heat will degrade in flavor faster than properly stored spices. Unless there's something holding the flavor in, it will disappear rapidly.
Soaking rice will allow the rice to absorb some of its water at room temperature, which is relatively friendly to flavor compounds. Because some of the water is soaked in, the cooking time is lessened, thus preserving flavor. It's said that the flavor of basmati rice is what suffers when it's not soaked, rather than the texture, so that reaffirms my suspicions.