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Vinegar, Made with a Vinegar Plant
Boil half a pound of coarse brown sugar and half a pound of treacle in two gallons of water, stir it well, put it into a large jar, and when it is lukewarm put on it a vinegar plant. Let it stand in a warm place for two months or more, when the liquor will have turned to vinegar. Boil the vinegar, strain it, and bottle for use. Keep it in a cool place. The vinegar plant is a fungus which grows in the liquor in warmth and darkness. If left without the liquor, it will die. A plant may be purchased often at a trifling cost: market people are the most likely to sell it. It will form in vinegar casks, and when it is used, a young plant will grow on the old one, which can be applied to the same purpose. In country places it is often spoken of as the "mother."
A household method for growing your own vinegar from sugar, treacle and a mother. It works, but the original leaves out the two things that decide whether you get vinegar or a spoiled jar: air and warmth.
- The hinge: air, not a sealed lidAcetic fermentation is aerobic. The jar must be covered with a cloth or coffee filter tied down against flies, never stoppered. Sealed, the liquid stalls at weak alcohol and goes musty.
- What a "vinegar plant" isThe mother is a cellulose mat built by Acetobacter, the same thing sold today as mother of vinegar or floating in bottles of unfiltered cider vinegar. A few tablespoons of live raw vinegar will seed the jar just as well as buying a plant from market people.
- GallonsCassell's is British: two imperial gallons is about 9 litres, not 7.6. Half a pound each of sugar and treacle in that volume is a weak wash, which is why it takes months and yields a mild vinegar.
- TreacleBlack treacle is the nearest thing to unsulphured blackstrap molasses; golden syrup is a poor substitute, being far more refined and much lower in the minerals and other nutrients the culture feeds on. Coarse brown sugar means an unrefined raw sugar such as demerara or muscovado.
- It needs yeast firstSugar water cannot become vinegar directly. Wild yeasts must turn the sugar to alcohol before the acetic bacteria convert it, which is a good part of why the original allows two months. Adding a pinch of bread or wine yeast at the start makes the process far more reliable.
- Warmth"A warm place" means roughly 21-29C (70-85F) held steady. Below about 15C the culture sulks; much above 35C it stalls and may be killed. Darkness matters less than the book suggests, but direct sunlight should be avoided.
- Know the mother from mouldA leathery beige or greyish mat on the surface is the plant. Fuzzy green, black or blue growth is mould and the whole batch goes out, plant included.
- Boiling before bottlingThe final boil is pasteurisation, killing the culture so the vinegar stops sharpening in the bottle. Holding it at 70C (160F) for a few minutes does the same job without driving off as much aroma. Save a piece of the mother in a little of the unboiled vinegar before you heat the rest.
- Do not use it for canning or picklingHomemade vinegar of unknown strength cannot be relied on for preserving. Safe pickling requires vinegar of at least 5 per cent acetic acid; unless you test yours with titration strips, keep it for the table and dressings.
Household vinegar-making of this kind was ordinary domestic economy in nineteenth-century Britain, where bought vinegar was often adulterated and a jar behind the kitchen range cost almost nothing to keep going. The "plant" the entry describes is what we now call the mother, and Cassell's is careful to note the country name for it; the same growth appears in cider and beer casks left standing, and the entry itself observes that it will form in vinegar casks. That it is called a fungus reflects the state of knowledge when the Dictionary was compiled - Pasteur's studies of the 1860s established that acetification was the work of a living organism, though its identification as a bacterium came later, and the older language persisted in domestic manuals for decades. The use of treacle rather than wine or cider is telling: this is a recipe for households without an orchard or a cellar, building vinegar out of the cheapest sweet thing in the larder.