This section is from the book "Every-Day Dishes And Every-Day Work", by E. E. Kellogg. Also available from Amazon: Larousse Gastronomique.
Peel four large potatoes, and put them to boil in two quarts of cold water. Tie two loose handfuls of hops securely in a piece of muslin, and place in the water to boil with the potatoes. When the potatoes are tender, remove them with a perforated skimmer, leaving the water still boiling. Mash them, and work in four tablespoonfuls of flour and two of sugar. Over this mixture pour gradually the boiling hop infusion, stirring constantly, that it may form a smooth paste, and set it aside to cool. When lukewarm, add a gill of lively yeast, and proceed as in the foregoing recipe.
To one teacup of very smoothly mashed, mealy potato, add three teaspoonfuls of white sugar, one teaspoonful of salt, and one cup of lively yeast, or one cake of Yeast Foam, dissolved in a very little warm water. The potato should be warm, but not hot enough to destroy the yeast. Allow this to stand until light, when it is ready for use.
 
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