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Rose Coloring
Mix together one-fourth ounce each of powdered alum and cream tartar, one ounce powdered cochineal, four ounces loaf-sugar, and a salt-spoon soda. Boil ten minutes in a pint pure soft water; when cool bottle and cork for use. This is used for jellies, cake, ice-cream, etc.- Mrs W. E. H., Minneapolis.
A homemade liquid food colour, made by extracting carmine from dried cochineal and fixing the shade with acid, alum and a pinch of alkali. The chemistry is the whole point of the recipe, and it is worth understanding before you start.
- Why alum, cream of tartar and soda are all thereCochineal's colour is pH-sensitive: acidic conditions push it orange-red, neutral to slightly alkaline push it toward crimson and purple. The cream of tartar acidifies, the salt-spoon of soda pulls back toward true rose, and the alum acts as a mordant that deepens and stabilises the shade. Change the proportions and you change the colour, not just the strength.
- Salt-spoonA salt-spoon is roughly a quarter teaspoon. Measure it level; more soda will turn the syrup magenta-purple.
- Loaf sugarSugar sold in a hard cone or loaf, chipped and pounded before use. Ordinary granulated white sugar is the same refined product. Four ounces is about half a cup.
- Powdered alumPotassium aluminium sulphate, sold as food-grade pickling alum in the spice aisle (some grocery alum is the ammonium form, also food-grade). Do not substitute a hardware-store product. A quarter ounce is roughly a teaspoon and a half by volume.
- CochinealDried, ground bodies of the scale insect Dactylopius coccus. Still legal and widely used as carmine or E120, but rarely stocked as loose powder; look to dye or specialist baking suppliers. One ounce is a large amount of a very strong colourant.
- Pure soft waterWater low in calcium and magnesium. Hard tap water will dull the colour and can throw a haze with the alum. Distilled or filtered water gives a cleaner result.
- Strain before bottlingThe original skips this, but ground cochineal leaves a fine grit that settles and clouds anything you tint. Pour the cooled syrup through two layers of muslin or a coffee filter.
- Keeping itHalf a cup of sugar in a pint of water is nowhere near a preserving concentration, so this is not shelf-stable despite the corked bottle. Refrigerate and discard at the first sign of mould or fermentation; a few weeks is realistic.
- Yield and useAbout a pint of concentrate, which is a lifetime's supply for a household. It is potent: start with a few drops per cup of icing or cream and build up. Note that carmine causes reactions in a small number of people and is not vegetarian.
Before coal-tar dyes reached the domestic kitchen, cochineal was the colour of anything meant to be pink: blancmange, ice cream, sugar icing, and the red-tinted jellies that mattered so much to a Victorian table. The insects were harvested from prickly pear cactus in Mexico and Central America and had been a major colonial export since the sixteenth century, valuable enough that Spain guarded the source for generations. A recipe like this reads half like a prescription: these had been dye-house materials that a careful housekeeper borrowed for the pantry. Buckeye Cookery (1877, and much reprinted) includes it because tinted icing was the ordinary occasion for wanting rose colour. Commercial synthetic food colours displaced homemade cochineal extract over the following decades, though carmine itself never disappeared and is still listed on plenty of modern labels.