S32 Marrep Mit 
heated air, is not as economically and as efficiently utihzed as heat 
in the form of steam applied in steamed-heated metal drums. 
While, as previously shown, the spray-drying process is the only 
process of desiccating milk, that preserves the original solubility of 
the milk, this advantage is lost in the case of buttermilk. ‘The acid 
in the buttermilk has changed the casein from its fine emulsion, 
such as it represents in normal milk, to a condition which renders 
the particles of casein, or curd, incapable of permanently remulsi- 
fying. ‘Phe curd in commercial buttermilk does not stay in emul- 
sion, but settles to the bottom. Hence nothing is gained by drying 
the buttermilk by the more expensive process of spray-drying. ‘The 
film process, which is the more economical, is therefore better 
adapted for the manufacture of buttermilk powder than the spray- 
drying process. 
It is advisable to precondense the buttermilk, before desiceat- 
ing, at the ratio of about 2:1. 
One gallon of buttermilk yields about .72 pounds of buttermilk 
powder, or the manufacture of one pound of powder requires 
about 1.39 gallons of buttermilk. ‘The cost of manufacture is esti- 
mated at about 2 cents per pound of buttermilk powder or about 
1.44 cents per gallon of buttermilk. 
Whey powder is manufactured in a similar manner. — Its chief 
value lies in its usefulness in the diet of infants and invalids, with 
whom the consumption of casein produces digestive disturbances. 
Since fresh whey is often not obtainable, the whey powder, the good 
keeping quality of which permits of keeping it on hand, furnishes 
an admirable substitute. When made from sour whey, it offers 
many advantages in cooking and baking and should be especially 
well suited for such dishes as pan cakes, ete. 
MALTED MILK.' 
Definition..-The produet known as malted milk is that re- 
sulting from the combination of whole nulk with the extract of 
malted barley and wheat flour, and the mixture is reduced to a dry 
form by desiccation in vacuo. 
History of Malted Milk Industry.—The process of the manu- 
facture of malted milk was invented by Mr. William Horlick, of 
: 1Tnformation on Definition, History and Process of Manufacture, received 
through the courtesy of Horlick’s Malted Milk Co., Racine, Wis., March §&, 
1918. 
