Other Soap-Coloring Options
If the natural colorants don’t work for you, or are too expensive or unpredictable,
there are a variety of synthetic colorants that can be used. Pigments, micas, and
FD&C colorants are some of these.
Pigments are colorants that were originally mined, but now, due to FDA
regulations, are manufactured in laboratories. Many natural oxides contain toxic
materials, so the FDA chose to approve only synthetic colorants for use in soaps and
cosmetics. The synthetically made pigments have the same molecular structure as the
natural ones, but they have a low enough concentration of toxic metals that they are
considered “safe” by the FDA. Pigments tend to be pretty stable, and the color that
they will impart to your soap is predictable. The liquids are extremely easy to use, but
the powders must be mixed with liquid before they are added to the soap batter, and
they may clump. The easiest way to liquefy the colorant powder is to put a tiny bit of
rubbing alcohol into a bowl – ¼ teaspoon is probably enough – and then add some
powder. Mix until all of the powder has dissolved in the alcohol. Mix the solution
into the soap batter at the correct stage; if the batter is not your desired hue, mix
more colorant solution. Another method of mixing the powdered colorant is to
combine it with liquid glycerin, in a ratio of 2 parts glycerin to 1 part colorant
powder. (The advantage of the liquid colorants is that this process is unnecessary; the
colorant can be added, one drop at a time, until the soap has achieved the desired
hue.)
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