press, most frequently worked by hand; when
pressure is applied, the oil flows down into a channel by which it is
conveyed to a receptacle or tank.
When oil ceases to flow, tepid water is poured upon the bags to carry
off oil retained by the bags. The pulp is then removed from the bags,
ground again in the mill, then replaced in the bags, and pressed a
second time. The water used in the process of making oil must be quite
pure; the mill, press, bags, and vessels sweet and clean, as the least
taint would ruin the quality of the oil produced.
The oil which has collected in the tank or receptacle just mentioned
is removed day by day, and the water also drained off, as oil would
suffer in quality if left in contact with water; the water also, which
necessarily contains some oil mingled with it, is sent to a deposit
outside, and at some distance from the crushing house, which is called
the "Inferno," where it is allowed to accumulate, and the oil which
comes to the surface is skimmed off from time to time. It is fit only
for manufacturing purposes.
After the second pressing the olive-pulp is not yet done with; it is
beaten up with water by mechanical agitators moved by water-power, and
then the whole discharged into open-air tanks adjoining the crushing
house. There the crushed olive kernels sink to the bottom, are
gathered up and sold for fuel, fetching about 12 francs per 1,000
kilos, while the _debris_ of the pulp is skimmed off the surface of
the tank and again pressed in bags, yielding a considerable quantity
of inferior oil, called "olio lavato," or washed oil, which, if
freshly made, is even used for food by the poorer classes. The pulp
then remaining has still further use. It is sold for treatment in
factories by the sulphide of carbon process, and by this method yields
from seven to nine per cent. of oil, of course suitable only for
manufacturing purposes. Only the first two pressings yield oil which
ranks as first quality, subject of course to the condition of the
fruit being unexceptionable. New oil is allowed to rest a while in
order to get rid of sediment; it is then clarified by passing through
clean cotton wool, when it is fit for use.
The highest quality of olive oil for eating purposes should not only
be free from the least taint in taste or smell, but possessed of a
delicate, appetizing flavor. When so many favorable conditions are
needed as to growth, maturity, and soundness of the fruit, coupled
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