The clearing of coffee is a circumstance demanding particular attention. After the heaviest parts of the grounds have settled, there are still fine particles suspended for some time, and if the coffee be poured off before these have subsided, the liquor is deficient in that transparency which is one test of its perfection; for coffee not well cleared has always an unpleasant bitter taste. In general, the coffee becomes clear by simply remaining quiet for a few minutes, as we have stated; but those who are anxious to have it as clear as possible employ some artificial means of assisting the clearing. The addition of a little isinglass, hartshorn shavings, skins of eels or soles, white of eggs, egg shells, etc., has been recommended for clearing; but it is evident that these substances, to produce their effect, which is upon the same principle as the fining of beer or wine, should be dissolved previously, for if put in without, it would require so much time to dissolve, that the flavour of the coffee would vanish.
Coffee-making devices of this period in England, in addition to the Rumford type of percolator and the popular coffee biggin, included Evans' machine provided with a tin air-float to which was attached a filter bag containing the coffee; Jones' apparatus, a pumping percolator; Parker's steam-fountain coffee maker, which forced the hot water upward through the ground coffee; Platow's patent filter, previously mentioned, a single vacuum glass percolator in combination with an urn; Brain's vacuum or pneumatic filter employing a "muslin, linen or shamoy leather filter" and an exhausting pump, designed for kitchen use; and Palmer's and Beart's pneumatic filtering machines of similar construction.
Cold infusions were common, the practise being to let them stand overnight, to be filtered in the morning, and only heated, not boiled.
Coffee grinding for these various types of coffee makers was performed by iron mills; the portable box mill being most favored for family use. "It consisted of a square box either of mahogany or iron japanned, containing in the interior a hollow cone of steel with sharp grooves on the inside; into this fits a conical piece of hardened iron or steel having spiral grooves cut upon its surface and capable of being turned round by a handle." There was a drawer to receive the finely ground coffee. Larger wall-mills employed the same grinding mechanism.
In 1855, Dr. John Doran wrote in his "Table Traits":
With regard to the making of coffee, there is no doubt that the Turkish method of pounding the coffee in a mortar is infinitely superior to grinding it in a mill, as with us. But after either method the process recommended by M. Soyer may be advantageously adopted; namely, "Put two ounces of ground coffee into a stew-pan, which set upon the fire, stirring the coffee round with a spoon until quite hot, then pour over a pint of boiling water; cover over closely for five minutes, pass it through a cloth, warm again, and serve."
From observations by G.W. Poore, M.D., London, 1883, we are given a glimpse of coffee making in England in the latter part of the nineteenth century. He said:
Those who wish to enjoy really good coffee must have it fresh roasted. On the Continent, in every well-regulated household, the daily supply of coffee is roasted every morning. In England this is rarely done.
If roasted coffee has to be kept, it must be kept in an air-tight vessel. In France, coffee used to be kept in a wrapper of waxed leather, which was always closely tied over the contained coffee. In this way the coffee was kept from contact with any air.
The Viennese say that coffee should be kept in a glass bottle closed with a bung, and that coffee should on no account be kept in a tin canister.