Whey is the watery portion of milk remaining after milk coagulation and removal of the curd. Whey can be obtained by acid, heat, and rennet coagulation of milk. There are two types of whey. Sweet Whey: Sweet whey is manufactured during making of rennet type hard cheese like cheddar or Swiss cheese. Acid Whey: Acid whey (also known as sour whey) is obtained during making of acid type of cheese such as cottage cheese. In addition to its liquid form, whey is also produced in the following solid forms: Whey solids or powder: This is obtained by drying the liquid whey and used as milk replacement in bakery products, ice cream, dry mixes and beverages. Whey Protein Concentrate: is the dry portion of whey obtained by the removal of sufficient non-protein constituents from whey so that the dry product contains not less than 25% protein. Most of the whey used in different food products is obtained as sweet whey from rennet types of hard cheeses. Whey is concentrated to obtain sweet/acid whey powder, condensed whey, Delactose powder as the primary products and protein, lactose as secondary products.