Fresh cow’s milk, condensed milk and soy milk have one thing in common: they contain proteins. These are important for our nutrition. These proteins become solid when they come into contact with a sufficiently strong acid, such as phosphoric acid, which is contained in cola. How do proteins from different types of milk react with cola?
Why does milk not like cola?
You will need
- Different kinds of milk
- Water glasses
- Measuring jug
Let’s get started!
1. Measure cola
Take a measuring jug and pour 100 ml of cola into each of the three glasses.
2. Add different types of milk
Add one tablespoonful of milk to each glass:
Low-fat UHT milk
The photo shows the glasses immediately after adding milk to the cola.
3. Observation after 15 minutes
Observe what has happened: Can you see whether the color has changed in all the glasses? Can you see whether any solids have formed (this is also called "flocculation")? Are there any differences?
4. Observation after one night
Leave the three jars overnight and look at them again afterwards. What has happened overnight? -> Depending on the type of milk, the proteins have flocculated to different degrees and settled at the bottom of the jars. By adding the acid (cola), the milk proteins could be separated as solids.