Rice Varieties.
Sticky rice and basmati are both rice and both mostly starch. The difference is the shape of a few per cent of the starch molecules.
Rice starch is two molecules (V.3): amylopectin, large and branched, which swells and makes a sticky gel; and amylose, long and straight, which holds grains firm and separate and recrystallises quickly when cold (VII.3). The ratio decides how a variety cooks. Glutinous rice (糯米), despite the name, has no gluten — it has almost no amylose, so it cooks into a chewy, cohesive mass, the rice of 粽子, 汤圆 and mochi. Japonica rice (粳米) — Japanese and northern Chinese short-grain — and jasmine have low amylose and cook moist, soft and slightly clinging, good for chopsticks and sushi.
Long-grain indica (籼米) and basmati have intermediate to high amylose and cook dry, fluffy and separate, best for pilafs, biryani and fried rice (XXI.4). Higher-amylose rice also needs a little more water, keeps its shape in long cooking, and turns hard in the fridge sooner. The grain's shape follows the variety roughly — short and round for japonica, long and slender for indica — but amylose, not shape, makes the texture. The workshop compares varieties.
Below: the amylose content of common rice types (typical values within the breeders' classes), the type you choose highlighted, and how quickly its cooked grains firm in the fridge relative to jasmine (course retrogradation model scaled by amylose).
- Explain amylose and amylopectin in rice.
- Match a rice to a dish.
- Explain why glutinous rice is sticky.
- Predict which rice hardens in the fridge.
Choose rice by the texture you want
In this teaching model, after six hours in the fridge jasmine rice has firmed to about 0.59 of the way, long-grain indica to 0.74 and glutinous rice to only 0.05: high-amylose rice makes the best day-old fried rice and the hardest cold leftovers, and glutinous rice cakes stay soft longest. Reheating with a splash of water and a lid softens any of them again for a while (VII.3).
Practical pairings: japonica for everyday Chinese and Japanese meals, onigiri and sushi; jasmine for Thai and southern Chinese meals; basmati for pilaf and biryani (XXIX.6); long-grain indica for fried rice and dishes that want separate grains; glutinous rice, soaked for hours and steamed rather than boiled, for 糯米鸡, 粽子 and sweets (XXVI.8); risotto rices (arborio, carnaroli) are medium-grain japonica types with a starchy surface that dissolves into the sauce. Rinse rice until the water runs nearly clear to remove loose surface starch, except for risotto, where that starch is the point.
Cook jasmine and basmati the same way, chill both overnight, and press a few grains of each between your fingers.
Terms
- Amylose
- Straight-chained starch: firm, separate grains.
- Amylopectin
- Branched starch: soft, sticky grains.
- Glutinous rice
- Rice with almost no amylose; sticky and chewy, but gluten-free.
- Japonica and indica
- The two main subspecies of Asian rice.
Sources
- Rice amylose classes used by rice breeders (IRRI; B. O. Juliano, Rice Chemistry and Technology, 3rd ed., 2003): waxy (glutinous) 0–2 %, very low 3–9 %, low 10–19 % (most japonica and jasmine), intermediate 20–25 % (many basmati), high above 25 % (many long-grain indica); higher amylose cooks drier, fluffier and firmer and hardens faster when cold.
- A teaching value chosen for the course: the right order of magnitude and shape, not a measurement of a particular food.
- H. McGee, On Food and Cooking: The Science and Lore of the Kitchen, 2nd ed., Scribner, 2004.