This section is from the book "The Manufacture Of Liquors, Wines, And Cordials, Without The Aid Of Distillation", by Pierre Lacour. Also available from Amazon: Manufacture of Liquors, Wines, and Cordials, Without the Aid of Distillation.
Used as a ferment in wines, etc, is made in various ways. It is made of mealy potatoes boiled thoroughly soft. They are then skinned and mashed as smooth as possible, when as much hot water should be put on them as will make a mash of the consistency of good beer yeast. Add to every pound of potatoes two ounces of molasses, and when just warm stir in two large spoonfuls of yeast for every pound of potatoes. Keep it warm till it has done fermenting, and in twenty-four hours it will be fit for use. A pound of potatoes will make near a quart of yeast. Another kind of yeast is made as follows: - Take half a pound of fine flour, the same quantity of brown sugar, and a quarter of a peck of bruised malt, boil these over a fire for a quarter of an hour in a half gallon of water, then strain this liquid into a jug, and when cool add one pint of artificial yeast or sour dough. The mixture will soon begin to ferment. It should be kept in a warm place, and when ebullition ceases the yeast will sink to the bottom; pour off the clear liquor, and the yeast will be fit for use.
Artificial Yeast. - Honey, five ounces; cream of tartar, one ounce; malt, sixteen ounces; water at 122° F., three pints; stir together, and when the temperature falls to 65° cover it up, and keep it at that temperature till yeast is formed.
Patent Yeast is made by taking half a pound of hops and two pailfuls of water, mix and boil until reduced to one pailful, and strain the decoction into the seasoning tub, and when sufficiently cool add half a peck of malt; in the meantime put the hops strained off again into two pailfuls of water, and boil to one gallon as before, and then straining the liquor while hot. When the liquor has cooled to about blood heat, strain off the malt, and add to the liquor two quarts. This yeast can be made in about eight hours.
2. Boil one pound of good flour, two ounces of brown sugar, and half a tea-spoonful of salt in one gallon of water, for half an hour, and when milk-warm bottle and cork it. It will be fit for use in thirty-six hours.
3. A pint of milk-warm water made to the consistency of a batter with wheat flour; to this add a pinch of salt, a tea-spoonful of sugar. Allow it to stand near the fire, or in a sunny position with a piece of glass over the top of the cup. Let it stand thus for nine hours.