Milk
Different forms of milk are used in the bakery. The kinds of milk used are liquid whole milk, liquid skim milk, liquid butter milk, sweetened condensed whole milk, sweetened skim milk, evaporated milk, powdered whole milk, powdered and flaked skim milk.
Whole milk we know is taken from the cow, skim milk is produced by removing the butter fat from the whole milk, butter milk is that product which remains when the butter fat has been extracted from the separated cream, the sweetened condensed whole milk is made by adding sugar to whole milk and then condensing it until it becomes of the required consistency.
Powdered whole milk may be made by first condensing whole milk until considerable of the water has been removed and then forcing it through a small aperture into a heated room where nearly all of the remaining water is removed and the milk comes down as whole milk solids possessing from 22% to 4% of moisture. Another way of producing this powdered milk is to force the milk through an aperture into a warm room in which the air is being circulated. By this method the moisture is removed after it leaves the spray. Powdered whole milk can also be made by allowing a very thin stream of milk to flow on to polished steel drums so constructed that the interior is filled with steam which makes the outer surface of the drum have a temperature of 212 degrees F. As the thin stream of milk falls on the drum the water is driven off and leaves a thin film of milk solids having from 22% to 4% of water. This film is continually scraped off on one side and goes off into a container from where it is conveyed into a sifting apparatus that forces the film through sieves as fine as powder.
Powdered skim milk is produced in the same manner as powdered whole milk. Large quantities of powdered milk are being used by the bakers to-day. Powdered milk makes an excellent form of milk for the baker, especially in places where liquid milk can not be bought cheap. The low price of powdered milk makes it possible to replace water in yeast doughs with milk without increasing the material cost of these doughs. It is possible because high grade milk powder will take on from 60% to 65% of its own weight of water which produces a paste having about the same consistency as dough. Then again doughs which have liquid milk in place of water will not lose so much during fermentation and baking which makes it possible to weigh the dough lighter. The extra dough gained in this practice is sufficient to off-set the cost of milk used, providing the price of bread does not go abnormally low and the price of milk is not raised abnormally high. 1