Why Purple Flowers Don’t Always Make Purple Soap

Why Purple Flowers Don’t Always Make Purple Soap

One of the most common assumptions among beginning soapmakers is that purple flowers will create purple soap.

Unfortunately, cold process soap rarely cooperates with that expectation.

The alkaline environment created during saponification changes many pigments found in flowers. Lavender petals often turn brown. Some botanical infusions fade entirely. Others produce unexpected shades of gray, tan, green, or brown.

This is one reason natural soapmaking remains so fascinating.

Nature does not always behave according to our expectations.

Many plant pigments are sensitive to pH. Cold process soap begins in a highly alkaline environment, and under those conditions, some natural pigments change the way they absorb and reflect light. Anthocyanins, the pigments found in many red, blue, and purple flowers, are especially vulnerable. In acidic environments, they may appear pink, red, purple, or blue. In alkaline soap, they often fade, brown, gray, or disappear.

Alkanet root is a perfect example. It does not simply fade. Sometimes it wanders.

Depending on the infusion strength, oil choices, temperature, gel phase, and cure conditions, alkanet can shift from purple to smoky lavender, gray-purple, gray-green, taupe, brown, or even a surprisingly beautiful woodland-camo shade during cure.

The color you pour is often not the color you unmold, and the color you unmold is not always the color you have six weeks later.

That is why successful soapmakers test, document, and observe. When working with natural soap colorants, experimentation is more valuable than assumptions.

Each batch becomes part science project, part artistic exploration, and part patient conversation with nature.

— LORDS SOAP AND SKIN LAB