Milk is around 90% water with trace amounts of lipids, carbohydrates (lactose), proteins (caseins), minerals and vitamins. These materials are not dissolved but instead remain suspended in the form of tiny particles invisible to the eye.
Milk is naturally white because the caseins (proteins) found in milk cluster together with phosphate and calcium to form tiny particles called micelles.
Scientifically speaking, particles either reflect, refract, or deflect light but since the particles in milk (micelles) do not absorb light, it refracts and scatters resulting in milk appearing white.
The Composition of Raw Milk
As soon as the milk leaves the udder, it contains:
|Mineral salts and Vitamins||1%|
To put it bluntly, when you buy cheese, you are mainly buying water. The longer the affinage or aging, the lower the water content.
To produce 1 liter of raw milk, the udder of the cow must filter 400 liters of blood.
Also read: Why is Butter Yellow? (SIMPLIFIED)
Why Whole, Skim and Low Fat Milk Do Not Have the Same Color
The way the rays of light react varies depending on the components of the milk, which affects the final color.
This explains why full-cream, whole, semi-skim, skim, and low-fat milks do not have the same color.
They do not have they same color because they do not have the same level of fat as raw milk.
A skim milk, which has less fat and calcium-rich protein, will be slightly bluish.
To put it simply, the more fat contained in the milk, the whiter it is. Or you could put it the other way, the lesser the fats, the lesser white you will see.
Milk Color Also Depends on the Diet of the Animal
The milk of corn-raised cows will be less ivory in color than that of cows grazing the natural green pastures.
This is because grass is high in carotene, a natural pigment of milk.
Why Goat’s Cheese is Whiter than Cow’s Milk Cheese
Goat’s milk and cheese are whiter because goats do not assimilate the carotene in grass in the same way as cows: the carotene passes into cow’s milk but not goat’s milk.
Furthermore, goat’s cheese is often matured for shorter periods so its interior does not have the time to evolve, hence the extra white texture.
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