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Yeast, Patent
"To make a yeast gallon of this composition--such yeast gallon containing eight beer quarts--boil in common water eight pounds of potatoes as for eating. Bruise them perfectly smooth, and mix with them, while warm, two ounces of fine honey and one beer quart of common yeast. For making bread, mix three beer pints of the above composition with a bushel of flour, using warm water in making the bread. The water should be warmer in winter than in summer, and the composition should be used a few hours after it is made. As soon as the sponge, or the mixture of the composition with the flour, begins to fall the first time, the bread should be made and put into the oven." This recipe is copied from the original specification in the patent office.
This is a leaven, not a bake: a potato-and-honey ferment intended to be pitched into a bushel of flour the same day it is made. The quantities are patent-specification quantities and need scaling down hard.
- Use it freshThe instruction that governs everything is "used a few hours after it is made." A potato ferment of this kind peaks quickly, then sours and loses lift as wild lactic bacteria overtake the yeast. Held overnight it will smell sharp and raise bread poorly.
- Beer measures"Beer quart" and "beer pint" are the old ale measure: a beer quart is about 1.15 litres (roughly 4.9 US cups), a beer pint about 575 ml. The "yeast gallon" is simply defined in the text as eight of those quarts, about 9.2 litres -- twice an ordinary gallon, so do not read it as one.
- Scale of the batchEight pounds of potatoes yields something over two US gallons of ferment. Only three beer pints of it go to a bushel of flour, so one batch would serve roughly five bushels. A bushel of flour was reckoned at roughly 42 to 50 lb depending on the trade, so this is a baker's quantity. A tenth of the recipe is closer to household use.
- "Common yeast"This means barm -- the live, liquid yeast skimmed from brewing or bought from a brewer. There is no exact modern substitute; the nearest is an active liquid starter or a slurry made from fresh baker's yeast, and any modern conversion is an approximation rather than a translation.
- Why honeyTwo ounces of honey in nine litres is too little to flavour anything. The likely purpose is a little immediately fermentable sugar to start the yeast before the potato starch is broken down.
- Potatoes "as for eating"Boil the potatoes until fully soft and mash them without lumps. Mix the honey and barm in while the mash is warm rather than hot -- yeast begins to suffer above about 110F and is killed nearer 130-140F.
- Water temperatureThe direction to use warmer water in winter is simply aiming at a moderately warm dough; the recipe gives no figure. Modern practice is to measure the water rather than guess by season.
- Reading the sponge"Begins to fall the first time" is the signal: the sponge domes, cracks and then sinks slightly at the centre. That is the moment of maximum activity, and the point after which a wild ferment starts to go acid.
Patent yeasts belong to the long stretch before reliable commercial yeast, when bakers depended on barm from a brewery and were at the mercy of its condition. Potato ferments were one common answer, since boiled potato supplies both starch and the mineral nutrients yeast wants, and variations on this kind of formula circulated widely in nineteenth-century cookery books. What makes this entry unusual is that Cassell's has not paraphrased a cook but transcribed a patent specification -- the flat legal phrasing, the careful definition of the "yeast gallon", the insistence on beer measure; the text itself says it is "copied from the original specification in the patent office." Yeast and baking powders were the subject of numerous patents in the period, and the compilers of a reference dictionary evidently thought the original wording worth preserving. Compressed and later dried yeasts, sold in standardised cakes from the later nineteenth century onward, made the whole genre obsolete.