Boil two ounces of the best hops in four quarts of water for half an hour; then strain and let stand until lukewarm. Put it in an earthen bowl, add half a cupful each of salt and brown sugar, and a quart of flour; mix all well together, and let it stand forty-eight hours. Now add six medium sized potatoes, which have been boiled and mashed through a colander, and let stand for another day, then strain and bottle and it is fit for use. While making it must be kept near a fire and often stirred. This yeast ferments of itself and needs the aid of no old yeast. If care be taken to let it ferment sufficiently in the bowl, it may immediately be corked tightly. Be careful to keep it in a cool place, and before using shake the bottle briskly. It will keep in a cool place two months, and is best the latter part of the time. Use about the same quantity as of other yeast.