How do you get the starch out of the potato?

potatoes laying on white tray with kitchen knife

You can buy potato starch from the grocery store. This is a white powder that has similar properties to flour, so it can be used to thicken sauces, for example . Or you can use it to make glue. The name "potato starch" already tells you that the starch comes from potatoes. But how do you get the starch out of the potatoes?

Before you get started

If you are experimenting at home:
1. Let your parents know and discuss the experiments with them beforehand.
2. Do not eat or drink at your workspace.
3. Wash your hands thoroughly before and after the experiment.
4. Be careful and cautious with the materials.

Graphic figure boy pouring liquid in flask

potatoes, grater, measuring jug and plastic bowls

You will need

4-5 medium potatoes
1 grater
2 plastic bowls
1 tea towel
1 refractory dish, e.g. small casserole dish

Let’s get started!

1. Peel the potatoes

Peel the potatoes and make sure that you work cleanly – that way you can still use them after the experiment.

grater with pealed potato in plastic bowl

2. Grate the potatoes

Use the grater to grate the peeled potatoes into a plastic bowl. Take care of your fingers so that you don't hurt yourself on the grater!

plastic bowl containing grated potato in water

3. Mix with water

Add 300 ml of water to the grated potatoes and stir the mixture with a tablespoon for 5 minutes.

white tea towel covering bowl with grated potato on it

4. Squeeze out the juice

Place a kitchen towel over a second plastic bowl and pour the grated potatoes and water over the towel in the second bowl. Use the cloth to wring the grated potatoes over the bowl and collect the juice in it.

hand squeezing yellow juice from white tea towel ball

5. Repeat

Pour the squeezed potato mixture back into the first bowl, add 200 ml of water and stir. Put the cloth over the other bowl again and pour the mash over it. Press it out again with the cloth. After squeezing, leave the squeezed juice to stand for 5-10 minutes until the starch settles at the bottom.
If you have worked cleanly, you can use the grated potatoes to make potato pancakes.

close up of plastic bowl with starch residue and water

5. Drain the water

Slowly and carefully pour the juice into the sink. Make sure that the starch sticks to the bottom of the plastic bowl. Scrape the starch into an ovenproof dish and dry it in the oven at 50°C.

Did you know?
Making adhesives from plants, is that possible?

Answer:

Yes, there is a whole range of plant substances from which adhesives can be made. Even the Stone Age people used birch pitch to glue their spearheads. Tree resins are inherently very sticky, as anyone who has ever touched a resinous branch knows. Starch is also an important raw material. This is contained in a great many plants: Potatoes, grains and lentils are great sources of starch. Sugar can also be used in adhesives. Sugar is obtained from sugarcane, for example.