It's so tempting when dreaming up your soap recipes to want to mix in some dried flower petals. Crushed rose petals, lavender buds, bluebonnets...there are so many to choose from. Adding flowers works just fine in melt and pour soap, but unfortunately, very few flowers retain their color in cold process soap
. Exposure to the lye in the saponification
process makes them turn brown or black as the soap cures. That doesnt prevent you from using them; Just realize that the red rose petals will become black rose petals, and the lavender buds will become little brown buds.
About the only commonly available flowers that will retain their original color are calendula flowers, or pot marigolds. I use them in many soaps including the one shown above. It is scented with a blend of spearmint, clove and neroli (orange blossom) essential oils, and had the lightly shredded calendula flower petals added to the soap right at trace. They retain their color beautifully, and add a lovely texture to the soap.