Say cheese!

Say cheese!

What do you get if you mix vinegar and milk?

What you need:

  • Milk - it works best with full fat or semi-skimmed
  • Vinegar
  • Glass
  • Kitchen towel

How to:

1. Pour milk into the glass until its around 1/4 full.


2. Add 2-3 tablespoons of vinegar to the glass. Stir. What can you see?


3. Place a piece of kitchen towel on top of a second glass. Slowly pour the mixture through the kitchen paper. You should be left with a white, plastic-y looking substance in the kitchen towel and the liquid in the other glass. You might need a few pieces of kitchen towel to get rid of all the liquid.


What does the white solid look like? Can you squeeze it together and get rid of more of the liquid? Don't eat it - it won't taste very nice!


Experiment with milk that contains different amounts of fat. What happens? What do those mixtures look like?

What's happening:

You've made cheese! Although the stuff you make won't taste very nice, you've created cheese in a similar way to commercial cheese makers.

Milk contains a protein called casein, which is negatively charged. Vinegar contains hydrogen ions, which are positively charged. The hydrogen ions and casein proteins attract each other and form the white, plastic-y lumps. The lumps are called curds and the process of forming the lumps is called curdling. The liquid is called whey.

Cheese makers don't normally use vinegar to curdle milk - they normally add an enzyme called rennet, which causes the milk to separate into curds and whey.

What cheese did your mixture look like? It should look a little bit like cottage cheese. Cottage cheese is just the curds sieved from the whey. Other cheeses, like cheddar, are pressed for a long time to remove more of the liquid. Some cheeses, like smelly Stilton, have bacteria or fungi added to them whilst they age, which gives them a different flavour.

To find out more about using bacteria and fungi in cheese, go to Mighty Microbes.