Galen, second century AD. The physician Claudius Galenus described a ceratum refrigerans — a cooling cerate — of white wax, olive oil and water, sometimes with rose petals. Pharmacopoeias carried it as Unguentum Aquae Rosae, rose water ointment, into the twentieth century, and it is still an official preparation in some. There are very few recipes of any kind with an unbroken eighteen-hundred-year production history.

Why it feels cold. The name is literal and the mechanism is simple physics: the cream is a water-in-oil emulsion, so applying it spreads a lot of finely divided water over your skin. Evaporation takes latent heat from the skin, and you feel it as cooling. A pure oil or an anhydrous balm cannot do this, which is why it was valued as a cooling application long before anyone cared about moisturising.

What actually holds it together. Not the beeswax alone. Vigorous beating shears the water into droplets a few micrometres across, and at that size Brownian motion keeps them suspended faster than gravity can bring them together; the wax raises the viscosity so far that the droplets can barely move at all. It is a kinetically stabilised emulsion, not a thermodynamically stable one — which is a technical way of saying it is always slowly separating, and Galen's separated too. His was made in small quantities and used fresh.

The improvement, and why this blueprint leaves it out. Nineteenth-century pharmacists found that adding a little borax transforms the stability: borax reacts with free cerotic acid in the beeswax to form a soap, and that soap is a genuine emulsifier. Most twentieth-century cold cream formulae, including the classical USP one, contain borax — and that USP formula also contained spermaceti from sperm whales, long since replaced. Borates are now classified in the EU as toxic for reproduction and are restricted in cosmetics there. This blueprint gives the borax-free Galenic original: less stable, shorter-lived, and containing nothing that needs a restriction. If you read an old formula calling for sodium borate, that is what it was for and that is why modern products use something else.

Personal Care

Blueprints (2)

Gillette Safety Razor

Cold Cream