Milk is healthy. It contains proteins, minerals and, in addition to water, fat. How much varies from milk to milk. We show you here how you can distinguish water from fat spots with a simple experiment. You can also use the method to find out whether the milk contains a lot or little fat.
Making milk fat visible - we show you how!
You will need
- Oil (e.g. sun seed oil)
- Milk samples
- Pipettes or small spoon
- Filter or blotting paper
Let’s get started
1. Get to know the grease spot test
Take a piece of filter paper and draw two circles on it with some space between them. Label the circles with "water" and with "oil". Now drop one or two drops of water into the circle labeled water and one or two drops of oil into the other circle.
2. Dry the wet spots
Blow dry the filter paper with a hair dryer. The easiest way to do this is to hold the paper in place on the table with a pencil in one hand and the hair dryer in the other.
3. Distinguish between water and oil spots
Distinguish between water and oil spots. What happens to the water and what happens to the oil stain when you blow dry? What you can see is that the water has completely evaporated. The oil stain can still be seen on the filter paper after blow drying!
4. Perform the fat stain test with milk
Now you can perform the grease spot test with different types of milk. To do this, you only need to drop one or two drops of each type of milk onto a filter paper and then blow dry it. Compare: How big is the greasy stain with condensed milk? How big is the stain with low-fat milk?
(Schlagsahne=Cream (30% fat), Kaffeesahne=coffee milk (10% fat), Vollmilch= Whole milk (3,5% fat) Hafermilch=Oat milk (2% fat)