Home › The Principles of Cookery › Yeast, Baker's
Yeast, Baker's
Put two ounces of hops into a saucepan, and pour over them one gallon of cold water. Bring the liquor to the boil, and keep it boiling, stirring well for one hour. Strain it, and mix with it two pounds of malt. Cover, and leave it till it is the heat of new milk. Stir into it briskly half a pint of solid brewer's yeast, let it work for ten hours, strain through a sieve, and it will be ready for use.
This is a barm — a home-brewed liquid leaven, kept alive by feeding a hopped malt wort with brewer's yeast. It behaves like a very loose sourdough starter and needs the same respect for temperature and cleanliness.
- The hinge: pitch at blood heat"The heat of new milk" is conventionally taken to mean about 98F/37C. Pitching into wort much above 100F stresses the yeast, and hotter still (roughly 120F upwards) will kill it; much colder and the ferment stalls and gives spoilage bacteria a head start.
- UnitsAn imperial gallon is 160 fl oz, or about 1.2 US gallons (roughly 4.5 litres). Half a pint of imperial measure is 10 fl oz. Two ounces of hops is a large amount by modern brewing standards and gives a strongly bitter, keeping liquor.
- Add the malt off the boilThe malt is stirred into the strained hot liquor, not boiled with it. Malt enzymes are denatured above about 170F, so if any sugar conversion is wanted the liquor should be allowed to drop to roughly 145-158F before the malt goes in, though the recipe itself says nothing about cooling at this stage. The two pounds of malt most likely means crushed malt grain rather than modern malt extract or malted milk powder.
- "Solid brewer's yeast"This is thick barm skimmed from a fermenting beer, sold moist and pasty by the brewery. Cake yeast or a slurry from an active starter is the nearest equivalent; a supermarket sachet of dried yeast will start the ferment but the character will differ.
- Why the hopsHops are here as much for preservation as flavour. Their acids suppress lactobacilli and other bacteria, which is what allowed a barm to be kept for days in an unrefrigerated pantry.
- Ten hours, then strainTen hours at room temperature is right for a warm kitchen. In a cool one the ferment will be sluggish and want longer; look for a foaming, yeasty head rather than the clock.
- Keeping and quantityThe finished barm is perishable. Keep it cold and stoppered loosely so gas can escape, and use it within a few days; if it smells sharp, vinegary or cheesy rather than beery, discard it. This makes close to a gallon of leaven, far more than a single bake needs; old books give varying proportions of barm to flour, so expect to test your own.
- What to expect from the breadBarm-raised loaves rise more slowly than those made with modern commercial yeast and carry a faint hop bitterness and beery aroma. That flavour is the point, not a fault.
Before packaged yeast became reliable and cheap, much of the bread in Britain was raised on barm — the living froth skimmed off fermenting beer — though leaven and other methods persisted alongside it, and the fortunes of the baker were tied to those of the brewer. Barm was inconsistent, often sour, and in bad weeks simply unobtainable, so household and trade manuals carried recipes like this one for extending a small quantity of brewer's yeast into a large batch of hopped, malt-fed leaven that would keep. Hops served the same function here as in beer itself: their bitter acids hold back the bacteria that turn a barm rank. By the time Cassell's dictionary appeared in the later nineteenth century, compressed German-style yeast was spreading fast through the trade and would soon make this preparation obsolete — such recipes belong to the last generation of cooks who might still have needed them.