This section is from the book "A Treatise On Beverages or The Complete Practical Bottler", by Charles Herman Sulz. Also available from Amazon: A Treatise On Beverages.
These are prepared by subjecting the juicy and non-juicy fruits to pressure, whereby the juice is liberated. The sound fruits are crushed, packed into a felt or flannel bag and expressed. The fruits should be carefully selected, and the rotten ones separated, which, if used with sound fruits, would act destructively upon the juice. Non-juicy fruits, such as apples, pears, are rasped or ground, and of apricot, peach, prune and cherry, the kernels are removed previously to pressing. On a large plan this is done by grating these fruits on sieves with meshes large enough for the pulpy mass to pass through, but retaining the kernel; a better plan is to cover them with water, and boil to a pulp in a close wooden or enameled vessel (no tin-lined or iron vessels should be used), by steam or fire. The liquor is allowed to drain off, and the pulp is subjected to pressure to obtain the retained liquor. On a small scale, the kernels are removed by hand.
The best method of expressing the juice is by means of a wooden filter press, as illustrated by the following engraving. The mill attached will grind and crush apples, pears, grapes, currants, etc. It is also a practical cider press. Metal presses are unfit for this purpose, and the metallic tincture press illustrated on page 500 is likewise unfit for expressing fruit-juices; also wood presses with metallic parts that come into contact with the juice, must be decidedly avoided, as all fruit juices contain fruit acids, which would act on the metal and the juice become contaminated. Limes, lemons, and oranges are peeled before subjecting them to pressure, the peels being a valuable material for preparing the volatile oils or the tinctures of peels, as directed in the previous chapter. On a small scale the juicy fruits are mashed in a basin to a pulp, put into a linen cloth, and pressed out by hand, and non-juicy fruits are placed in an ena meled vessel (no others should be used) and boiled to a pulp, the liquor drained off, and the pulp pressed out in a linen cloth.
It is of importance in the preparation of fruit juices to prepare them as much as possible without heat, or if the latter be applied, to perform the pulping in a closed vessel, as the fine aroma of the fruit is impaired by it. If the pulping has been done on a large scale and a considerable quantity of water has been employed, the liquor or juice should be concentrated at a low temperature, which is essential in order to save the aromatic parts. This is best done in a vacuum apparatus.