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Make glue from milk

Do you know you can make homemade glue from milk? All you need is milk, white vinegar and baking soda. The vinegar is used to split milk into curds and whey.

This fun kitchen science experiment is very simple but requires adult help to heat the milk.

Image of curds separated from milk in a hand

How to make glue from milk

What you need:

Milk

White vinegar

Baking soda ( bicarbonate of soda )

Pan

Water

Strainer

Make glue from milk

First, you need to split the milk into curds and whey.

  • Heat 1 and a half cups of milk in a pan; once warm, add 3 teaspoons of white vinegar.
  • Keep heating and stirring the mixture, and you should see the curds ( solid part ) and whey ( liquid part ) separate.
curds and whey from milk in a pan
Curds and whey
  • Strain the mixture using a sieve. You should be left with solid lumps which can be moulded to make a ball. These are the curds.
  • Place the solid mixture back in the pan and add a little water and a tablespoon of baking soda.
  • Heat the mixture until it starts to bubble.
  • Give the mixture a good stir and leave it to cool. You can now use it as glue. You might need to add a little more water or baking soda until you get the right consistency. It should look like a thick paste.
  • I tested ours by sticking two egg boxes together ( both contain eggs, so they are heavy ). It worked!!!
two eggs boxes stuck together with glue made from milk

How can you make homemade glue from milk? Why does it work?

Here’s what happened to the milk. The vinegar creates a chemical reaction which makes the milk separate into two parts, a solid (the curds), and a liquid (the whey). The curds are milk protein, called casein. Liquid casein is a natural glue.

When you add the baking soda, it neutralises the vinegar ( which is acidic ). The bubbles are caused by carbon dioxide gas being given off as part of the reaction. The curds form a liquid again after being neutralised.

More science experiments using milk

Learn about emulsions with a colourful milk display made with milk and dish soap.

Curds can also be used to make small decorations. In the early 1900s milk was sometimes used to make buttons and other items! You can find out more about this in my book Gross Science!

collage of gross history experiments including milk split into curds and whey, a vegetable mummy and toilet paper for an absorbency test

Last Updated on February 15, 2023 by Emma Vanstone

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22 Comments

  1. It’s very interesting. I have this idea in my mind but I haven’t realize it yet. Every sunday we do a scientific experimet and maybe one of the next sunday we will make it.
    Greetings from Ital

  2. This is awesome. Going to do this tomorrow. Then I’ll take it a next step. My daughter wants to know if add in borax would have the same effect on this glue as store glue.

  3. I recall reading that the very earliest Bell Helicopters – the one with the clear bubble –
    used casein to mold the bubble. This was because they could mold casein, but
    did not yet have the technology to make the bubble out of acrylic resin.

    They had a big incentive to develop the acrylic bubble. If left out in the rain, the
    casein bubble tended to turn “milky”.

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