Rice, Pasta And Getting Starches Right

Rice and pasta fail in opposite directions, one turning to paste and the other staying hard in the middle. Both outcomes come from how starch granules behave in hot water.

Gelatinisation is the process at work

Starch is stored in granules that are insoluble in cold water. Above a certain temperature they absorb water rapidly, swell and lose their structure, which is what makes a grain tender.

The temperature at which this happens differs between starches, which is why rice, pasta and potato all behave differently in the same pan of boiling water.

Once the granules burst, the starch is released into the liquid. Whether that is desirable or ruinous depends entirely on which dish is being cooked.

Rice depends on a fixed water ratio

Absorption cooking gives the grain exactly the water it needs, so nothing is poured away and the released starch stays on the surface of the grains.

Too much water leaves the grains sitting in starchy liquid as they finish, which is what produces a claggy result rather than separate grains.

Rinsing before cooking removes loose surface starch from milling, which is why rinsed rice separates and unrinsed rice clings. Neither is wrong, and each suits different dishes.

Pasta needs volume and movement

Pasta releases starch continuously into the water, and a small pan becomes thick enough that the pieces stick to each other and to the base.

A large volume keeps the concentration low and holds the temperature steady when the pasta goes in, since a small quantity of water is cooled sharply by a cold load.

Stirring in the first minute matters most, because the surface is at its stickiest before the outer layer has fully hydrated.

The cooking water is an ingredient

Starchy pasta water thickens a sauce and helps it cling, because dissolved starch acts as an emulsifier between fat and water.

This is why a sauce finished with a little of the cooking water coats the pasta evenly while the same sauce added to drained pasta slides off it.

The same principle explains risotto, where the starch is deliberately worked out of the grain into the liquid to create the texture rather than being washed away.

Resting, cooling and reheating

Rice left covered off the heat continues to steam and the moisture redistributes through the grain, which is why the last few minutes off the hob improve the texture noticeably.

As cooked starch cools it partially recrystallises, which firms the texture and is why cold pasta and day-old rice feel different from freshly cooked.

Cooked rice needs prompt cooling and proper refrigeration, because it can harbour spores that survive cooking and multiply at room temperature, and reheating does not undo that.