How does rice get from fields to our plates?

1. Rice grows in flooded fields called paddies. The water keeps weeds down. After about four months the plants turn golden, heavy with grain.
2. The field is drained and the stalks are cut. Then they are beaten or shaken so the grains fall off. That is called threshing.
3. Fresh grains hold a lot of water. Spread out in the sun, they dry. Dry grain does not get moldy, and it does not get squashed in the machines.
4. Each grain wears a hard coat called a husk. Two rubber rollers rub it off and a fan blows it away. What is left is brown rice.
5. Brown rice still has a thin brown layer called bran. A polisher can rub the bran off to make white rice. This step is a choice.
6. The rice is bagged and sent to shops. At home it is boiled. Each grain soaks up water, swells and turns soft.

Tap the parts of the plant, then look into the round glass: it shows one grain, cut open.

• Panicle. The panicle is the drooping head at the top of each stalk. It holds a hundred or more grains.
• Stem and leaves. The leaves use sunlight to make the plant's food. The stems are hollow, like drinking straws.
• Roots in the mud. The roots hold the plant in the mud under the water and take in water and minerals.
• Husk. The husk is the hard outer coat. It protects the grain, but people cannot eat it, so the mill rubs it off.
• Bran. Bran is the thin brown layer under the husk. Brown rice keeps it. White rice has had it polished off.
• Germ. The germ is the part that would sprout into a new rice plant. It is small but full of good things.
• Starchy middle. The white middle is packed with starch, the food the baby plant would use to grow. White rice is just this part.

Dry the rice, then switch on the husker and the polisher. Look in the round glass to see what lands in the sack.

Experiment: What happens if you send wet rice straight into the husker?

1. Leave the rice wet and switch on the husker. Look at the grains in the round glass.
2. Now dry the rice a little at a time and watch the broken grains.
3. Dry it as far as you can. Is that better or worse?

What we found: Wet grains are soft, so the rollers squash and break them. Grains that are dried too much turn brittle and crack. In between there is a just-right dryness where almost every grain comes out whole.

Turn on JavaScript to try it yourself.

A shop wants brown rice with at least 85 of every 100 grains whole. Set up the mill, then run the batch.

Rice is the seed of a kind of grass. It feeds more than half of the people on Earth. Most rice grows in flooded fields called paddies. Rice plants do not need to stand in water, but they do not mind it, and most weeds cannot live there. So the water works like a weed blanket.

When the plants turn golden, the field is drained and the stalks are cut. Shaking or beating the stalks knocks the grains off. This is called threshing. Each grain is still wrapped in a hard husk, a bit like a peanut in its shell.

Next the grain has to dry. Fresh grain is damp inside. Damp grain grows mold in the storehouse, and it is so soft that machines squash it. So the grain is spread out in the sun or blown with warm air until it is dry enough, but not so dry that it turns brittle and cracks.

At the mill, rubber rollers rub off the husks and a fan blows them away. What is left is brown rice, which still has a thin brown skin called bran. A polisher can rub the bran off to make white rice. White rice keeps longer and cooks faster. Brown rice keeps more fiber and vitamins. The peanut picture is not perfect: a rice husk is rubbed off, not cracked open.

Key words

Paddy

A flooded field where rice grows. Rice still in its husk is also called paddy, or rough rice.

Threshing

Knocking the grains off the cut stalks.

Husk

The hard outer coat of a rice grain. People cannot eat it.

Bran

The thin brown layer under the husk. Brown rice still has it.

Endosperm

The white, starchy middle of the grain.

Moisture content

How much water is inside the grain.

Check your thinking

1. What does the husker take off the grain?

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   The hard husk. The rollers rub off the hard husk. Brown rice comes out.

2. Why is rice dried before it goes to the mill?

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   Wet grain goes moldy and gets squashed in the machines. Mold needs water, and soft, damp grains break between the rollers.

3. What is the difference between brown rice and white rice?

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   White rice has had its brown bran rubbed off. Both are the same grain. Polishing takes the bran off brown rice and leaves white rice.

4. The rollers in the husker are set far too close together. What happens?

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   Grains get crushed. Rollers that squeeze too hard break the grains. Too far apart, and husks stay on.

5. A mill starts with 100 kilograms of dried rough rice. About how much white rice can it make?

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   About 70 kilograms. The husk is about 20 percent of the weight and the bran and germ about 10 percent, so roughly 70 percent is left.

6. Why does rice get bigger and softer when it is cooked?

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   The grains soak up hot water and swell. The starch inside each grain takes in water and swells.