Page:The Olive Its Culture in Theory and Practice.djvu/175

Rh on the liquid becomes tinged with purple from the coloring matter in the berry. Admitting the definition as correct, we should have five possible qualities of palatable oil, and two, suitable only for manufacturing purposes. It is unnecessary to say that Virgin oil as defined above is not an article of trade. A little is probably made on large estates, for the proprietors, and for their friends consumption, nor is it necessary to say, that the four possible edible oils are reduced to two or three. If a run is made without water, the second run will probably be made with hot water, or two runs without water and then the hot water or with cold water at once, and then hot water. Cold water is not injurious, but oil gathered by the hot water process is not as fine, and does not keep as well as that expressed without water or with the use of the cold. Extreme heat is dangerous to oil at all stages of expression and storage; and for this reason Italians doubt the safety of artificial drying even where they consider drying necessary or advantageous. After the expression of the oil, it separates from the water and small particles of the berry which have passed the sacks or cage, and rises to the surface, when it is carefully skimmed off and placed in other vessels to settle; thence drawn off again from the surface, and clarified by being passed through a layer of filtering cotton, filtering paper, or even bone charcoal. It is then fit to place in the storage receptacle. During the process of crushing, pressing, depositing and clarifying, too extreme cold chills the oil and checks its flow and clarification, and in cold weather it is desirable to have moderate artificial heat in the mill. When clarified, the oil should be put in a cool place, and in cool receivers, of which tanks of tiles, brick lined with marble, or glass, and the Italian glazed terra-cotta lined tanks are the best. The Italians use wooden tanks lined with tin and also brick tanks lined with a fine cement. Wood is not desirable, the oil which soaks into it is liable to turn rancid. Again wood alone, lacks the coolness required, at least in an Italian