Experiment 45

Put a drop of cream on filter paper; when dry, note the characteristic grease spot. This is a test for fat.

Experiment 46

Fill a tall cylinder with milk, and determine the specific gravity with a lactometer.

Experiment 47

Examine a drop of milk under microscope. Explain appearance and make a drawing of the fat globules seen.

Experiment 48

To 1/2 c. milk warmed to 100° F. add \ of a rennet tablet dissolved in 1/2 ts. water. Mix quickly. Let stand in a warm place until the milk clots. Break the clot lightly and put into a filter paper. Test the curd or casein for protein. (See protein test, page 69.)

Experiment 49

Test the filtrate from above experiment with Fehling solution for sugar.

Butter

Butter is made by separating the fat globules of cream by churning, after the cream has soured from the action of bacteria.

Composition of Butter (J. C. Olsen)

Butter fat is one of the most palatable, easily digested, and easily assimilated forms of fat. Its flavor is due to bacterial action. In the modern creamery all conditions are most sanitary; bacteria which give a disagreeable odor and taste to butter are not present. Butter is artificially colored, but the coloring is harmless.

Renovated butter is butter which has become rancid and is then subjected to a process of renovation, by which the disagreeable odors and flavors are removed. It is not an unwholesome product, but should not be sold at butter prices. Most states require that it be plainly marked "renovated" or "process" butter.

Oleomargarine Or Butterine

The manufacture of these butter substitutes is carried on under government inspection, and the products are clean and wholesome, lacking, however, the delicate flavor of butter. They are manufactured from a high grade of lard, cottonseed oil, and milk, and a small amount of butter is generally added for flavor. There is no objection to their use in cookery, and when they are sold under their true names and at a reasonable price, they are good substitutes for butter in cooking.

Experiment 50

Foam test to distinguish butter from oleomargarine. Melt in separate dishes butter, oleomargarine, and renovated butter. The butter boils quietly and produces considerable foam, while the other two sputter and crackle violently, producing but little foam.

Experiment 51

Beat one pint of ripened cream with an egg-beater or whip churn until the butter fat separates. Collect these lumps and form into a mass. Wash in cold water to remove any milk; drain off the water. Add salt to taste. Weigh the butter and estimate the cost. How much cream would be required to make one pound of butter? What is the composition of buttermilk?