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YEAST, PRESERVED (another way) (Whisk the yeast to a froth)
Whisk the yeast to a froth, and then with a paint-brush lay it on writing paper; continue coating the paper every time it dries, until a cake is formed, then divide it into square with a knife.
A method for drying live barm into storable cakes, from the days before packeted yeast. It works, but it assumes an ingredient and a paper that no longer exist in the form intended.
- What "yeast" meant hereIn a Victorian kitchen this is barm — the thick, live foam skimmed from fermenting ale, bought from a brewer or saved from home brewing. It is a wet slurry, not the granules sold today, and modern instant or active dry yeast cannot be substituted into this method because it has already been dried.
- The paper"Writing paper" of the period meant rag-based laid or wove paper, without the clay coating or optical brighteners of modern stock, though it was sized and so not especially absorbent. Modern printer paper is unlikely to behave the same way; unbleached parchment or a clean plate is the sensible stand-in.
- The hinge: dry cool, dry slowYeast is damaged by sustained heat above roughly 110F and killed around 130-140F, so every coat should dry in moving air at room temperature. Hurrying it in a warm oven or over a stove risks a handsome cake of dead yeast. Expect a long wait between coats and a day or more for the whole build-up.
- How many coatsThe recipe simply says continue until a cake is formed: repeated thin layers, each fully dry before the next, until the sheet is thick enough to be scored and lifted.
- Shelf lifeHome-dried barm will not keep as long as a modern commercial packet and loses vigour over time. Store the squares in a tightly closed jar somewhere cool and dark, and proof one in warm sweetened water before committing it to a batch of dough.
- ContaminationAir-drying an open live slurry over a day or two invites wild yeasts, moulds and lactic bacteria. Discard any cake that smells sour, cheesy or musty rather than of bread and beer.
Before packeted yeast, bakers and housewives depended on brewers for their leaven, and the supply was unreliable: barm went off in warm weather, and a household without a brewery nearby could be left with nothing but a sourdough starter or a chemical raising agent. Drying barm — onto paper, onto cornmeal, into bran-and-hop "yeast cakes" — was one common answer, and nineteenth-century cookery books carry several versions of it. The paper-brushing variant gives flat sheets that store without crumbling. Compressed fresh yeast reached commercial scale in the later nineteenth century and active dry yeast during the twentieth, and instructions like this one disappeared from household books soon after.