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Barm, to Make
With an ounce of isinglass dissolved in warm water mix half a pound of the best flour. Take two ounces of hops, and boil in a quart of water till it is reduced one half, then stir all together in a gallon and a half of warm water and a very small quantity of brewer's barm, and put in a warm place for two days. Probable cost, 1s. 4d.
This is not a dish but a leaven: a home-grown liquid yeast, kept alive on flour and bittered with hops, of the kind bakers relied on before packaged yeast was dependable. The whole thing hangs on the brewer's barm in the last line — it is the living culture, and everything else is food and preservative for it.
- Brewer's barmThe frothy yeast head skimmed from an actively fermenting ale. Nothing on a supermarket shelf is the same thing; homebrew shops sell live ale yeast, and a spoonful of unpasteurised beer sediment is the nearest household equivalent. Without a live culture the mixture simply spoils.
- IsinglassDried collagen from fish swim bladders, historically sturgeon, sold to Victorian kitchens as a clarifier and setting agent. Modern isinglass comes from other fish and is stocked mainly by brewing suppliers; plain gelatine behaves similarly here, and the recipe works without it, since its role is body and clarity rather than fermentation.
- ScaleA gallon and a half imperial is close to 7 US quarts, or about 6.8 litres. That is an enormous quantity of liquid barm for one household — a baker's or a large family's weekly supply. Quartering the whole recipe gives a more manageable jar.
- The hop waterTwo ounces of hops boiled down from a quart to a pint gives a strongly bitter, strongly antibacterial infusion. That bitterness is the point: hop resins suppress lactic bacteria while leaving yeast unharmed, which is what keeps a wet barm from turning sour for a few days.
- "A warm place"The recipe names no temperature; somewhere in the region of 75-80F is a reasonable modern reading. A Victorian warm place meant near the range or in the airing cupboard; a turned-off oven with the light on, or the top of a refrigerator, does much the same job. Too much heat and the culture is liable to sour.
- Two days, then use itLiquid barm peaks and declines. It should be foaming and smell of beer and bread by the end of the second day; once it smells sharply of vinegar or cheese it is finished. Keep it covered but not sealed — it produces gas — and refrigerate after it is active.
- How much to useThe original assumes you know. Older baking practice ran roughly to half a pint to a pint of barm for a quartern of flour, so figure on something near a cup of barm per large loaf, with a long rise. Treat that as traditional practice rather than a tested measure and judge by the dough.
- CleanlinessScald the vessel and any spoon or funnel. A wet flour-and-water medium at blood heat will grow whatever gets into it first, and the hop bitterness only buys you a margin, not immunity.
- That priceOne shilling and fourpence is given as the probable cost of the whole quantity, a fair sum in the 1870s.
Barm is the old English word for the yeast head thrown up by fermenting beer, and for most of the history of English baking it was simply a by-product of brewing — bakers bought it from brewers, or households collected it from their own small beer. The trouble was that barm was perishable, seasonal and hostage to whatever the brewer's fermentation was doing that week, which is why manuals of this period print methods for extending it: flour and water feed the yeast, boiled hops hold spoilage bacteria back, and isinglass gives the liquid body. Recipes of this kind fade out of cookery books as compressed yeast became reliable and cheap from the later nineteenth century, marking a moment of transition — the editors still assumed a reader who might have to build her own leaven, while the shop-bought cake of yeast was already arriving.