An easy and excellent mode of making domestic yeast
Sarah Rutledge, The Carolina Housewife, by a Lady of Charleston (Charleston, S.C.: W. R. Babcock & Co., 1847), 11.
Take as much hops as you can grasp in your hand; put to them a quart of water and two good sized Irish potatoes, washed clean and unpeeled, which, to facilitate their quick boiling, had better be cut up. Let them all boil together until the potatoes are well cooked. Then take the potatoes out, mash them up, skins and all, and put them again with the hops. After stirring this well together, pass it through a sieve, as dry as you can from the hops. While the liquor is hot sweeten it with the best brown sugar, to prevent the yeast being dark coloured. When the mixture is nearly cold add two table-spoonfuls of wheat flour, previously rubbed smooth with a little of the liquor, and then mix the whole. It ought to turn out near a quart of yeast. Bottle it rather loosely at first, but when the fermentation begins, cork it tight and tie down the cork. When made in the morning it will be fit to use at night, if attention is paid to these directions. A gill of this yeast is sufficient for a quart and a half of flour.