Cheat Sheet on Colorants – Botanicals
Solubility: Water soluble
Color range: Natural shades of red, pink, beige, brown, tan, green. Many morph from green to black in the product. Can be pH sensitive.
Oxidation/fading – yes. Especially prone to pH sensitivity and darkening/browning
Potency – low. Need a fair amount to get a dark color.
Botanicals (flowers from the garden, herbs from the herb garden, etc.) are one colorant that a LOT of crafters – especially soapers – love to use. Unfortunately, they are not all that potent, and you require a fair amount of most botanicals to achieve a strong color.
Home grown botanicals (or certified organic) are best, as you don’t want to add commercially-grown flowers (with all of the pesticides that may be on their surface) to your product. It’s also a very good practice to thoroughly dry all botanicals before adding them. This will ensure that there is no residual moisture in the botanical which can grow mold, mildew and bacteria in your product.
Botanicals are water soluble, but they tend to oxidize rapidly once they are exposed to moisture (for instance, once they are added to a soap). Since they also tend to be pH sensitive, you can expect them to shift to brown or black rapidly during saponification.
One of the best uses for botanicals is in bath salts and bath bombs. They color the dry product well and if they are sufficiently powdered/small pieces should wash down the drain with little mess. Make sure to use a light touch when adding botanicals, to avoid causing plumbing issues and leaving a lot of messy residue in sinks/tubs when people use your products.