There are various ways of making domestic yeast. One of the simplest, and perhaps the best, is the following, which was communicated to me by one of the best bread-makers I ever saw:
“Put into one gallon of water a double handful of hops;—boil them fifteen or twenty minutes, then strain off the water while it is scalding hot;—stir in wheat flour or meal till it becomes a thick batter, so that it will hardly pour;—let it stand till it becomes about blood warm, then add a pint of good lively yeast, and stir it well; and then let it stand in a place where it will be kept at a temperature of about 70° F. till it becomes perfectly light, whether more or less time is required; and then it is fit for use;—or if it is desired to keep a portion of it, let it stand several hours and become cool; and then put it into a clean jug and cork it tight, and place it in the cellar where it will keep cool; and it may be preserved good, ten or twelve days, and even longer.”
Another way by which yeast when thus made may be preserved much longer, and perhaps more conveniently, is, to take it when it has become perfectly light, and stir in good Indian meal until it becomes a hard dough: then take this dough and make it into small thin cakes, and dry them perfectly, without baking or cooking them at all. These cakes, if kept perfectly dry, will be good for several weeks and even months.
When yeast is needed, take some of these cakes (more or less according to the quantity of bread desired) and break them fine and dissolve them in warm water, and then stir in some wheat flour till a batter is formed, which should be kept at a temperature of about 60° F. till the yeast becomes light and lively, and fitted for making bread.
Others, in making this yeast, originally put into the water with the hops, a double handful of good clean wheat bran, and boil them up together and strain off the water as above described: others again, boil up a quantity of wheat bran without the hops, and make their yeast in all other respects as above described.
The milk yeast is greatly preferred by many; and when it is well managed, it certainly makes very handsome bread. The way of making it is simple. Take a quart of milk fresh from the cow, (more or less according to the quantity of bread desired,)—a little salt is generally added, and some add about half a pint of water blood warm, but this is not essential;—then stir wheat flour or meal into the milk till it forms a moderately thick batter; and then cover it over, and place it where it will remain at a temperature of from 60° to 70° F. till it becomes perfectly light. It should then be used immediately: and let it be remembered that dough made with this yeast will sour sooner than that made with other yeast; and also that the bread after it is baked will become extremely dry and crumbly much sooner than bread made with other yeast. Yet this bread, when a day old, is exceedingly light and beautiful: albeit some dislike the animal smell and taste which it derives from the milk.
In all these preparations of yeast and dough, it should ever be recollected that “the process of fermentation cannot go on when the temperature is below 30° F., that it proceeds quite slowly at 50°, moderately at 60°, rapidly at 70°, and very rapidly at 80°.”
If, therefore, it is desired to have the yeast or dough stand several hours before it is used or baked, it should be kept at a temperature of about 50°. But in the ordinary way of making bread, a temperature varying from 60° to 70°, or about summer heat, is perhaps as near right as it can well be made.
Prof. Thomson gives the following directions for making yeast in large quantities:—“Add ten pounds of flour to two gallons of boiling water;—stir it well into a paste, let this mixture stand for seven hours, and then add about a quart of good yeast. In about six or eight hours, this mixture, if kept in a warm place, will have fermented and produced as much yeast as will make 120 quartern loaves” (of 4 lbs. each.)
A much smaller quantity can be made by observing due proportions of the ingredients.