[Illustration: Danish churn ] The best temperature for churning varies from 48° to 56° and must be determined by local conditions and experience. To allow plenty of room for the cream to shake about, the churn should not be much more than half full. When the globules of fat suspended in the milk stick together and form granules as large as good sized pin-heads it is time to stop the churn and drain off the buttermilk. If the butter fails to “come” in half an hour or forty minutes it may be because the cream in the churn is too warm or too cold. A little cold or warm water, as the case may be, can be added as a simple remedy. [Illustration: Churning room in a large modern creamery ] Toward the end of the process care must be taken that the churn is stopped at the right moment, when the butter will separate clear from the buttermilk. After the buttermilk is drawn off pure cold water is poured into the churn and the butter granules are rinsed in it. This water again is drawn off and fresh cold water put in. [Illustration: Butter worker ] =Working the Butter.=—The butter can now be taken out with a sieve and worked on the butter-worker, or it may be worked in the churn. “Working” the butter consists in squeezing out the buttermilk and kneading the butter into a smooth but not “greasy” mass. If it is too warm and if it is worked too much, with a sliding motion instead of just pressing, the butter is apt to become greasy. If there seems to be any danger of greasiness, it is better to stop and put the butter in a cool place for a few hours to recover its elasticity. The working can then be finished safely. =Salting.=—During this working process salt is added and thoroughly distributed and worked in. About half an ounce of salt is used for a pound of butter. =Composition of Butter.=—When finished, the butter ought not to contain more than 12% to 15% of water, and there should be at least 80% of butter-fat. If all the butter-fat originally in the milk could be taken out in the butter, 100 lbs. of 4% milk should yield 4.88% (4.88 lbs.) of butter with 82% butter-fat. But a little is lost in the skim milk and more in the buttermilk, which usually contains ½% fat, so that about 4½ lbs. is all the butter that can be expected from 100 lbs. of milk. =Overrun.=—Creamery men are much interested in the “Overrun” which means the increase from the churn over the amount of fat in the milk. For instance, if a quantity of milk containing 100 lbs. butter-fat as shown by the Babcock Test produces 114 lbs. of finished butter, the overrun is 14%. The buttermaker who gets the largest overrun by reducing the loss of butter-fat in the skim milk and the buttermilk to a minimum, keeping the percentage of water in the butter just below 16%, and yet producing high scoring butter, is considered most efficient. =Packing.=—For the market, butter is packed in tubs or stone jars. Or it is molded in neat one-pound bricks and wrapped in parchment paper.