By Harold McGee
The aroma of standard white rices has green, mushroomy, cucumber-like, and “fatty” components (from 6, 8, 9, and 10-carbon aldehydes), as well as a slight popcorn note and floral, corn-like, hay-like, and animal qualities. Brown rices contain these and also small amounts of vanillin and maple-sugar-like sotolon. Aromatic rices are especially rich in the popcorn-like aromatic component (acetylpyrroline), which is also an important element in screwpine leaves, and cooked popcorn and bread crust. Because it is volatile and not regenerated during cooking, the popcorn aromatic escapes during cooking, and its concentration declines. This is one reason for presoaking aromatic rices; this step shortens the cooking and minimizes aroma loss.