Home › The Principles of Cookery › Acidulated Alkali
Acidulated Alkali
Grate the rind of two lemons upon four ounces of loaf sugar, pound it, and mix it thoroughly with two ounces of bicarbonate of soda and two ounces of tartaric acid. Bottle it, cork it closely, and keep in a dry place. A small tea-spoonful stirred briskly into half a tumblerful of water will make a pleasant draught, and it should be drunk during effervescence. Time to prepare, half an hour. Probable cost for this quantity, 6d.
A homemade effervescing powder — the Victorian ancestor of both sherbet and the fizzy antacid. It keeps indefinitely if it is kept genuinely dry, and fails completely if it is not.
- Dryness is the whole recipeBicarbonate of soda and tartaric acid react the moment moisture reaches them, so any dampness in the sugar, the mortar or the bottle will set the mixture fizzing in storage and leave you with a flat, faintly salty powder. Dry the sugar and the bowl thoroughly, work quickly, and store in a tightly stoppered glass jar rather than a tin.
- Loaf sugarLoaf or lump sugar was refined sugar sold in a hard cone or block, broken up and pounded as needed. Ordinary granulated sugar is the direct equivalent; caster sugar dissolves faster in the glass and needs less pounding.
- WeightsFour ounces of sugar is about 115 g (a little over half a cup), and two ounces each of soda and tartaric acid are about 57 g apiece. The proportions matter more than the absolute amounts, though equal weights of bicarbonate and tartaric acid do not quite neutralise one another and leave a little acid unreacted.
- Tartaric acidStill sold for home brewing, sugar work and confectionery, sometimes under the name of a fruit acid. Citric acid behaves similarly; do not substitute cream of tartar, which is a different, weaker salt.
- Grating the rind onto the sugarThe point of grating the lemons directly over the sugar is to catch the oil released from the zest in the crystals rather than losing it on a board. Take only the yellow layer; the white pith turns the powder bitter.
- PoundingA mortar gives the finest result, but a few short pulses in a spice grinder or small food processor works, provided everything is bone dry. Grind the zested sugar first, then fold in the soda and acid by hand so the two are not driven together under friction.
- Yield and strengthThe quantity given makes roughly eight ounces of powder, enough for perhaps thirty to forty glasses at a small teaspoon each. A level teaspoon in half a tumbler is a mild draught; a quarter of the powder by weight is bicarbonate of soda, which is worth knowing if you drink several.
- Drink it fizzingThe instruction to drink during effervescence is not decorative. Once the carbon dioxide has escaped, what remains is sweetened sodium tartrate solution, which is dull and slightly salty.
Effervescing powders sit on the boundary between the still-room and the medicine chest, which is exactly where a Victorian household dictionary liked to place them. Seidlitz powders, soda powders and similar preparations were dispensed by chemists throughout the nineteenth century as mild aperients and settlers of the stomach, and the domestic version here simply flavours the same chemistry with lemon and sugar so that it can be taken as a refreshment rather than a remedy. It belongs to an age that expected the cook to understand why an acid and an alkali make gas — the same reaction that raises a soda cake — and to keep a jar of it to hand in hot weather, before bottled mineral waters became cheap and universal. The same formula, dried harder and made sweeter, survives on confectionery shelves as sherbet.