( Originally Published 1926 )
229 Q. How is olive oil produced?
A. The oil is pressed from mature, ripe olives. The olives are first ground between stones, and the paste thus formed is put into closely woven baskets, which are piled one on top of the other and put into a hydraulic press. Many pounds of pressure are brought to bear upon this ground mass. The extract from this mass is the first oil, and is known as "Virgin," or "Extra Virgin," olive oil.
After the oil has been allowed to run for some time, the baskets of cakes are removed, beaten up with a club, softened with hot water, put back into the hydraulic press, and given an-other pressure of many pounds. This is second pressing oil, slightly inferior to the "Virgin" oil. There are several subsequent pressings, each producing a lower grade of oil than the one produced from the previous pressing.
230 Q. How many grades of olive oil are there?
A. Broadly speaking, edible olive oil can be classified into three distinct grades : First pressing oil, known as Virgin olive oil; second pressing oil; and a third grade, which is either a first or a second pressing of a somewhat inferior quality of olives. This third grade oil has a stronger flavor and a darker color than the first two grades.
231 Q. Why is there so little California olive oil on the market?
A. The demand for ripe olives is so great, that, in general, it pays better to use the olives in this way instead of crushing them for oil. Besides, the American olives are not so rich in oil as those that grow in southern Europe.
232 Q. How is corn oil obtained?
A. Corn oil is obtained from the germ of the kernel of the Indian corn. The shelled corn is first put into tanks of warm water. This immersion softens the kernel, which is then partially crushed through stone crushers. The resulting mass is submitted to a special process whereby the germ is separated. The germ is then dried and the oil pressed out.
233 Q. How does corn oil compare with lard, but-ter, and other cooking fats as far as the cooking itself is concerned?
A. Corn oil has a burning point of 650° F., as compared with only 425° for lard, 250° for butter, 535° for cottonseed oil, 600° for olive oil, and 620° for peanut oil. The high burning point of corn oil enables the cook to bring it to 600° before putting in food for frying. Thus the hot oil instantly seals in the food juices, retaining flavor and aroma, the food being cooked in its own juice instead of being saturated more or less with grease.
Corn oil also has a lower congealing point than any other salad oil, remaining clear and fluid down to 14° F., and so makes salad dressings which are free from lumps.
234 Q. For what is peanut oil used?
A. The most important use of peanut oil is that as salad oil. It is also used for seasoning and shortening. The very best use, however, of refined peanut oil is in the manufacture of oleomargarine and similar compounds.
235 Q. What is meant by "virgin" peanut oil?
A. Peanut oil obtained by the cold-pressed process. It is especially fine in flavor and requires no refining.