Whey originates as a by-product from cheese production using milk as raw material. Whey still contains many valuable components that have a wide utilization if treated properly in an appropriate process - such as simple evaporationdrying, or fractionation by ultrafiltration followed by other processes, usually also evaporation and drying.

 

The composition of fresh whey
Whey composition and quality depends on the type of cheese that is produced. Whey is usually classified depending upon its pH, e.g. acidity.

Type of whey pH Type of cheese or curd
Sweet whey 6,3-6,5 Swiss/Gouda
"Sweet" whey 5,9-6,3 Cheddar
Acid whey 3,9-5,9 Mozarella, Tvorog, Quark, Cottage cheese etc.
Acid (lactic) whey 4,5-4,6 Casein (lactic acid)
Acid (mineral) whey 4,5-4,6 Casein (K+, Na+, Ca++)

The composition of fresh whey from a conventional cheese production is approximately as follows:

Composition Approx. % of dry matter
Water 94.25%  
Protein 0.80% 13
Lactose 4.30% 75
Ash 0.55% 10
Fat 0.10% 2

However, it is well known that the above mentioned composition also changes by the use of different starter culture and different rennet types. Further, the milk composition, either due to seasonal variations or breed of cows has an influence on the composition of the whey. Generally speaking, the higher content of lactic acid and galactose, the more difficult the drying becomes.