How is fruit juice made?

1. Ripe apples are picked in the orchard. An apple feels solid, but most of it is water, hidden inside as juice.
2. At the factory the fruit rides along a belt. Rotten fruit, leaves and twigs are taken out, so only good fruit goes on.
3. Next the fruit is washed. Sprays of water and spinning brushes scrub away soil, dust and anything else stuck to the skin.
4. A mill with spinning teeth crushes the clean apples into a wet mush called mash. Crushing breaks open the tiny bags that hold the juice.
5. The mash is wrapped in cloth and squeezed in a press. Juice runs through the cloth. The skins, seeds and pulp stay behind as a dry cake.
6. The juice is heated for a short time to stop germs from spoiling it. Then machines fill clean bottles and seal them tight.

Follow the fruit from left to right. Tap each machine to see its job.

• Sorter. A camera looks at every fruit. When it spots a rotten one, a paddle flicks it off the belt into a bin.
• Washer. Jets of water and spinning brushes clean every fruit. The dirty water drains away underneath.
• Mill. Fruit drops into the hopper on top. Toothed rollers grab it and crush it into mash.
• Press. A heavy plate pushes down on mash wrapped in cloth. Juice flows out through the cloth and runs to a tank.
• Pasteurizer. The juice flows through hot pipes for a short time. The heat stops germs, so the juice stays fresh for longer.
• Filler. A nozzle fills each clean bottle with the same amount of juice. Then a cap is screwed on tight.

Both presses hold the same apples. Crush the apples in the right-hand press, then pull the pump handle down. The same push squeezes both. Which jug fills?

Experiment: Which gives more juice: whole apples, or apples that are crushed first?

1. Tap the apples in the right-hand press to crush them into mash.
2. Drag the pump handle down, or move the pressure slider.
3. Compare the two jugs and look at what is left in each basket.

What we found: The crushed apples gave far more juice. In a whole apple the juice is locked inside tiny cells, and squeezing mostly just dents it. Crushing breaks the cells open, so the press can push the juice out.

Turn on JavaScript to try it yourself.

Five machines, one right order. Tap them into place so muddy apples come out as bottles of juice, then run the line.

Bite an apple and juice runs down your chin. But before the bite, where was the juice? An apple is built from millions of tiny cells, a bit like very small water balloons packed tightly together. Each one has a thin wall with juice inside. That is why an apple can be mostly water and still feel firm.

To make juice, you have to break the cells open. That is the crusher's job. Its spinning teeth tear the fruit into mash, and juice spills out of every broken cell. If you put whole apples in a press, they would just get dented, and hardly any juice would come out.

Then the press squeezes the mash inside a strong cloth. The cloth works like a strainer. Juice goes through it. Skins, seeds and pulp cannot. Squeezing harder gets more juice, but only up to a point, because the last drops cling to the pulp.

Fresh juice does not keep for long. Tiny living things, too small to see, would soon spoil it. So the juice is heated for a short time, which stops them, and then sealed in clean bottles. Oranges are handled a little differently: machines cut them in half and squeeze each half, so the bitter peel stays out of the juice.

Key words

Cell

A tiny building block of living things. In fruit, each cell is like a little bag of juice.

Mash

Fruit that has been crushed into a wet mush, ready for pressing.

Press

A machine that squeezes mash so the juice runs out.

Pomace

The dry cake of skins, seeds and pulp left after pressing.

Pasteurize

To heat a drink for a short time so germs cannot spoil it.

Yield

How much juice you get from a given amount of fruit.

Check your thinking

1. Where is the juice before an apple is crushed?

   Show the answer

   Locked inside the apple's tiny cells. An apple is made of millions of cells, and each one holds a little juice.

2. Why is the fruit washed before it is crushed, not after?

   Show the answer

   After crushing, the dirt would already be mixed into the mash. The whole fruit, skin and all, goes into the crusher. Anything left on the skin would end up in the juice.

3. You press a basket of whole apples as hard as you can. What happens?

   Show the answer

   Hardly any juice comes out, because the cells are not broken. Whole apples keep their juice locked in. They need crushing first.

4. What is left in the press cloth after pressing?

   Show the answer

   A dry cake of skins, seeds and pulp. The cloth lets juice through and holds back the solid bits, called pomace.

5. Why is juice heated for a short time before it is bottled?

   Show the answer

   To stop germs from spoiling it. Heat stops the tiny living things that would make the juice go bad.