Why Milk is White

Milk is 87% water and 13% solids. It consists of about 5 percent lactose, 3.7 percent fats and 3.5 percent proteins. Casein is the most common protein and makes up about 80% of the proteins in milk. Also, casein's molecular structure is very similar to that of gluten. This is why many gluten free diets also are casein-free. It is the combination of casein and fats that give milk its color.

The color white results from all the wavelengths of visible light being reflected into the eye. Casein and certain fats reflect wide ranges of wavelengths, causing milk to appear white. Fat free milk appears a bit bluish due to reduction of fats reflecting light.

The pasteurization process that kills microorganisms in milk, also destroys the Vitamin C content, as well as significantly diminishes various other health benefits of milk.