Madder root powder is frequently used in soap making to lend a pink/reddish/burgundy colour to soap. It can be added directly into the soap mixture at trace to produce a lighter, sometimes speckled colour, or it can be infused in oil and strained, then used in the soap recipe to produce deeper, more saturated colours. A plant species in the genus Rubia, madder (INCI: Rubia tinctorum) is a climbing plant with small flowers and long roots. Madder root has been used for centuries as a dye for textiles and cosmetic products. Traces of madder have even been discovered in King Tut's tomb and in the ruins of Pompeii.
In soap, madder root powder produces colors ranging from light pink, deep red and mauve. The color it produces depends on the type of soap, the amount used and production variables such heat and application. When using natural herbs in soap, the herbs can be added at trace or infused in the soap making oils for a speckle-free look.