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Yeast, Economical Preparation Of
Thicken two quarts of water with four ounces of fine flour, boil it for half an hour, then sweeten it with three ounces of brown sugar; when almost cold, pour it, with four spoonfuls of baker's yeast, into an earthen jug deep enough for the fermentation to go on without running over. Place it for a day near the fire, then pour off the thin liquor from the top, shake the remainder, and close it up for use, first straining it through a sieve to preserve it sweet. Set it in a cool cellar, or hang it some depth in a well. Keep always some of this to make the next quantity of yeast that is wanted.
This is a liquid leaven — a barm kept alive by back-slopping, in the days before packaged yeast was reliable. It works, but the quantities assume a household baking several loaves a week.
- The hinge: keep a portion backThe last sentence is the whole point. Some of the finished barm inoculates the next batch (the book does not say how much), so the baker's yeast is bought once and need not be bought again.
- "Baker's yeast" is not a modern packetAt the time this meant wet barm skimmed from brewing or bought damp from the baker, roughly the consistency of thick cream. Four spoonfuls of that is a large, lively inoculation; a small quantity of modern dry yeast would stand in for it, though the two are not directly equivalent.
- Quantities in modern measureTwo quarts is about 2.3 litres of water by imperial measure, 4 oz flour is a scant cup, 3 oz brown sugar about 6 tablespoons. The result is a thin, sweet gruel — it should pour, not mound.
- "Near the fire" means 75-80F"Near the fire" means somewhere gently warm -- A warm kitchen corner, the top of a refrigerator, or a turned-off oven with the light on. The book sets no temperature; too much heat will sour the ferment rather than raise it.
- Use a vessel twice the volumeThe instruction about depth is a warning about the foam. A 4-quart crock or a wide-mouth jar filled halfway, covered with cloth rather than sealed, keeps the ferment from climbing out.
- Pouring off the thin liquorAfter a day the barm separates: a grey watery layer on top, active sediment below. That liquid is the alcohol and spent water, and it tastes harsh — discard it, then stir the sediment back into suspension.
- Straining "to preserve it sweet"Sweet here means unspoiled, not sugary. Sieving takes out coagulated flour lumps, presumably to keep the stored barm clean.
- Storage and shelf lifeA cool cellar or a bucket lowered down a well would be somewhere around 50F; refrigeration does the same job more reliably. The book gives no keeping time; expect the rising power to fade after a week or so, at which point the recipe's answer is to make a fresh quantity using some of the old.
- Using it in breadThe book gives no dosage. You will have to judge it: a generous quantity of active barm in place of part of the dough's liquid, with a rise of several hours rather than one.
Before compressed yeast became cheap and dependable in the late nineteenth century, home bakers are often said to have relied on barm — the yeast-rich froth skimmed off fermenting beer — or on a self-perpetuating flour ferment of exactly this kind. Brewers' barm was free or nearly so in a brewing town, but its supply was erratic and its flavour varied with whatever the brewery was making, so cookery books offered flour-and-sugar washes as a way to stretch a single good purchase indefinitely. The instruction to hang the jug in a well is a reminder that cold storage was hard to come by, and that a well shaft held a steady low temperature all summer. A household's yeast was infrastructure: the bread, the buns and the raised pies all depended on keeping the jug alive, and the economy of the title lies in never having to buy the leaven twice.