Tuesday, October 18, 2011

Soaking Details: Time And Temperature

Trouble: Dry rice tends to overcook, because it heats unevenly. While the inside is still dry, hard and undercooked, the outside get mushy, soft, overcooked and sticky. The usual result is porridge rice. This is worse with whole grain brown and wild rice than with white rice.

Whole grain brown and wild rice bran naturally keeps water and heat out. Newly harvested rice contains roughly 1/4 water (25%). Rice is preserved naturally by drying. Sun dried rice looses half its natural moisture, down to roughly 1/8 water (12%). Soaking returns the whole grains to normal harvest moisture (20-30%).

The moisture inside helps transfer heat, cooking more evenly and more quickly.

Soaking raises the moisture content and leaches starch. Once water penetrates the kernel, the water will help transfer the cooking heat from the outside to the inside, allowing the rice to cook evenly. (Dry white rice takes 15 minutes in boiling water for heat to reach the center of the kernel, and half that time, 6-8 minutes, for soaked rice.) Rinse the soaked rice to wash the leached starch, which would otherwise make the rice sticky.

Start soaking in the morning, or the night before. Dry rice is hard and crunchy like pebbles, similar to dry pasta. Wet rice will be hard but not crunchy and taste starchy. (There will still be water left, meaning absorption stops ~30%.)

Soak brown rice for at least 1 hour. Brown rice requires longer soaking than white rice. Measure and soak rice in the morning, for use in the afternoon or evening. 1 hour soaking raises moisture ~10%.

Dry rice is is around 10% moisture. Freshly harvested rice, and soaked wet rice, is 20-25% moisture. That’s twice as much water as dry rice. The maximum water rice holds is 30% moisture, if rice swims in water for a long time. That’s three times as much water as dry rice.

Hot water speeds soaking, but keeping water hot is probably too much work for a home kitchen preparation. A hot soak needs to be stay below cooking temperature, where starches gel, at 55-85C. The hottest soak possible is hot water tap temp of 50 C (122 F). 1 hour at 50 C (hot water tap temperature 122 F) raises moisture to 20%. 4x longer, longer 4 hours at 50 C is required to raise moisture to maximum 30%.

- 2 hours @ 25 C (room temp 77 F) = 20%
-1 hour @ 50 C (hot water tap temp 122 F) = 20%

At room temperature, soaking 36-48 hours brings moisture to an maximum 30%. It’s almost impossible to soak rice for too long.

Trouble: Eventually, brown rice will actually sprout at little rice plant! Try this: After soaking 1 day, the seed needs oxygen, so place in strainer on top a paper towel, and keep the paper towel moist, for 1-2 days.

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