Crude oil, or oil in its natural state, is that which is obtained from the blubber of the whale in the process of "trying out" on shipboard. The oil, then, which is taken from whale ships and carried to the oil manufactory, is said to be in its crude state. We will speak first of the manufacture of crude sperm oil.[J]
The first step in the process of manufacture, is to take the oil in its crude state, and put it into large kettles, or boilers, and subject it to a heat of one hundred and eighty to two hundred degrees, and then all the water which happened to become mixed with the oil, either on shipboard or since, will evaporate.
Winter Strained Sperm Oil. In the fall, or autumn, the oil is boiled for the purpose of granulation during the approaching cold weather. The oil thus passes from a purely liquid into a solid state, or one in which it is in grains, or masses.
Boiling Out.
When the temperature of the atmosphere rises, or the weather slackens during the winter, the oil which has been frozen, but is now somewhat softened, is shovelled out of the casks and put into strong bags that will hold half a bushel or more, in order to be pressed. The oil which is now obtained from this first pressing is called winter strained sperm oil.
Spring Sperm Oil. What remains in the bags after the first pressing, is again heated by being put into boilers, after which it is baled into casks again, and upon cooling, it becomes more compact and solid than it was before.
During the month of April, when the temperature is about fifty degrees, the oil becomes softened; it is then put into bags, and goes through a second process of pressing similar to the first. The oil from this pressing is called spring strained sperm oil.
Tight Pressed Oil. That which is left in the bags after the second pressing, is again melted, and put into tin pans or tubs which will hold about forty pounds each. When this liquid is thoroughly cooled, as each pressing makes what is left harder, in consequence of extracting the oil, the cakes taken from the tubs are then carried into a room heated to about ninety degrees; and as they begin to yield to the influence of this high temperature, or the remaining oil begins to soften the cakes, they are taken and shaved into very fine pieces, or ground up as in some instances, deposited in bags as hitherto, and put into the hydraulic press.
The room being at the temperature indicated above, and the bags subjected to a powerful pressure of three hundred tons or more, all the oil is extracted from them, and what is left is perfectly dry, free from any oily matter, and brittle. The oil thus obtained by this last pressing is called tight pressed, or summer oil.