HOW BUTTER IS FORMED.

Shannon News, 27 March 1925, Page 4

HOW BUTTER IS FORMED.

In these rapidly-moving times, the progress of science takes a foremos. place. As an instance, Soxhlet s ©la churning theory, dating 1876, is based upon assumptions which have proved upon investigation to be wrong, Soxhiet supposed that the rat of the cream remained liquid, that u. quid fat globules did stick together and that the concussion in the churn was necessary to solidify the fat and thus form the butter. Since then it has been shown that the fat of normally cooled cream is solid before the churning begins, and that even liquid fat at 32 degs. G. may be transformed into butter. . „ „ The usual process in the formation of butter may be explained as follows: In churning, air is the cream, and a foam is formed. The protein lowering the surface tension must accumulate in the newly-pro-i duced surfaces —i.e., the foam membranes—and since this same protein surrounds the fat globules, these are drawn into the foam and held there. Analysis shows that the liquid cream underneath the foam is gradually decreased in fat. In' the foairt the fat globules lie very close together, under the pressure of the two surface mem. branes, and thus fat clusters originate at first. These clusters are readily transformed into lumps if the fat 3 soft enough to yield to the pressure and these lumps stick together, ana thus rapidly increase in size. Finally the butter “breaks," the foam - collapses, either because the butter lumps become so large as to disturb the surface equilibrium, or because the protein in the foam membranes solidifies, and thereby loses its elasticity. All substances influencing the surface tension of milk’, of changing the hulls of the fat globules, as,' for example, alkali, retard or inhibit the churning. The high fat content ©1 buttermilk at high qhurning temptera. tures is caused by too rapid a formation of butter lumps before all the fat globules have been worked into the foam.