This series examines those colorants–animal, vegetable, and mineral–that appear in Victorian formularies. All links are non-affiliate and non-monetized.
Description. Carmine is the red natural dye made of ground-up cochineal beetles. It’s sort of the insect equivalent of beet dye–it can be very deep red and even purple, but in lighter amounts, it is a rosy pink.
Like many natural dyes, carmine reacts to pH. Alkalinity turns it more violet, and acidity turns it more orange.
History. The beetles were collected and used as dye by the Aztecs, and before them, the Mayans. Even after the Spanish took control of the area, it kept a firm hold on the carmine trade for a couple hundred years until the colonial era ended. It makes regular appearances in formularies, though alkanet seems to have been more popular, probably for being less expensive.
Carmine became less economical after the rise of cheap manmade dyes. Production fell, though it never went away completely. These days, many customers want to use natural dyes, so demand has risen somewhat. It is a little expensive because the supply has not risen in accord.
Names. Often it’s called “cochineal” in receipt books. The writers usually mean powdered carmine, but sometimes they specify “tincture of cochineal” or just “tincture cochineal”, carmine powder suspended in alcohol. (This source gives a recipe.)
Usage. Carmine, in powder and tincture form, appears dozens of times in general receipt books in many contexts, from typical (cosmetics, syrups, candy) to atypical (toothpaste).
Its reactive quality is manipulated by dyers in South America to get the desired colors of yarn for weaving. You can briefly see this in action here. I’ve heard that, above or below certain pH levels, the color will completely disappear, which is probably why I’ve never seen a cold process soap recipe with carmine in it.
A very small percentage of the population is allergic to carmine.
Vegetable alternatives. Alkanet root looks the most similar, but it fades more easily and doesn’t behave as predictably. Alkanet gives better results if it is soaked in a portion of the carrier oil for a few days, then strained through a washed and dried coffee filter. Fragments of the root powder left in a product will settle to the bottom.
Mineral alternatives. Iron oxide is sometimes offered as a vegan version of carmine, but it has little resemblance, being more of a brick red. Certain micas with dyes added come closer, but some customers wish to avoid dyes.
Synthetic alternatives. If you don’t care about dyes, most of the red lakes with a dash of Red 33 can readily approximate the color of carmine. Red lakes are usually too orange to be used alone.