whey the watery part of milk which is separated from the solid curds in cheese-making, is something of which the world has much too much. Yet, if better ways of utilizing it could be found, this surplus whey could be a valuable source of nutrition. Almost a third of the proteins in milk are left in the whey, as well as all the sugar.
The size of the problem is intractable: 10 kg (22 lb) of milk are needed, typically, to produce 1 kg (2.2 lb) of cheese. Between 6 and 9 kg (13–20 lb) of whey will be left over. The state of Wisconsin alone was reckoned not so long ago to produce half a million kg of cheese annually.