Carmine (Cochineal)

Carmine is the aluminium lake of carminic acid, the red compound that the scale insect Dactylopius coccus manufactures in its own body. The insects are farmed on prickly pear, brushed from the cactus pads, killed and dried; the colour is drawn out in hot water and then fixed onto an aluminium substrate, which turns a soluble dye into an insoluble pigment.^[1]

It survives in modern formulation because nothing else quite matches it. Something like seventy thousand dried insects are needed for a pound of dye, a ratio that made cochineal one of the most valuable cargoes leaving the Americas for three centuries.^[2]

The colouring principle is carminic acid, an anthraquinone carrying a sugar group. That sugar is the whole difference between it and the kermesic acid of European kermes: it makes the molecule more water-soluble and, in practice, a much stronger dye.^[3]

Commercial carmine is not carminic acid alone. It is a complex of the acid with aluminium, often with calcium as well, and it carries insect protein through from the extraction. Nor is it the same listed material as cochineal extract, the weaker aqueous preparation that United States regulation treats as a colour additive in its own right and requires to be declared under its own name.^[3]

Chromatographic work on pre-Columbian Peruvian textiles has identified a set of minor carminic acid derivatives that appear to fingerprint that region.^[4] Telling cochineal apart from the other insect reds is a coarser business, done on which main anthraquinone is present — carminic, kermesic or laccaic acid.^[3]

Cochineal was cultivated in Mesoamerica before the Spanish arrival and rendered as tribute in bagged form. After 1521 it became a controlled colonial export, concentrated in Oaxaca and shipped through Seville, and it is commonly described as the most valuable American export after silver.^[5]

Europe did not know what it was buying. The material arrived as hard dried grains, and whether those grains were seeds, berries or animals was argued over until eighteenth-century microscopy settled the question in favour of the insect.^[6]

In cosmetics the dye moved from the dyehouse to the dressing table as carmine lake, and by the time American cosmetics became an industry it was the standard red for rouge and lip colour.^[7]

As a lake, carmine behaves as a pigment rather than a dye. It is ground and dispersed rather than dissolved, and it sits on the surface instead of staining it.^[8] That is precisely why it works in a lipstick bullet, where a soluble dye would migrate into the skin and bleed at the lip line.

The shade shifts with pH and with the metal it is laked onto, running from orange-red through true crimson to a bluish purple. A single raw material can therefore support a wide range of finished colours, which is part of why it outlasted its competitors.^[9]

Carmine is permitted in cosmetics in both major jurisdictions. In the European Union it appears as CI 75470 in Annex IV to Regulation (EC) No 1223/2009, the positive list of colourants allowed in cosmetic products.^[10]

In the United States the Food and Drug Administration issued a final rule on 5 January 2009 in response to reports of severe allergic reactions including anaphylaxis. It requires foods to declare cochineal extract or carmine by name in the ingredient statement, and cosmetics to declare carmine prominently and conspicuously at least once in the labelling.^[11] The distinction matters: cochineal extract is not a listed cosmetic colour additive in the United States at all, so the cosmetic half of the rule speaks only to carmine. The agency confirmed the effective date of 5 January 2011 in a notice of 11 March 2009.^[12] The requirement is a labelling one: it exists so that people who react to the material can identify it, not because the colourant was withdrawn.