Berry powder in homemade glycerine soap

[camproses]

I made some glycerine soap from scratch using ethanol (rum), glycerin, castor oil, coconut, and olive and I want to color it with powdered lingonberries (red). Will the berry powder likely turn brown as it would in CP soap, or does the different process/formulation of glycerin soap eliminate that problem? I am trying to keep it as natural as possible, and the person who wants me to make it doesn't want artificial colorants (including micas etc.). The soap is already solid (though still a little moldable by hand) and cured. My plan is to soften it and add the berry powder to it. I would be using my hand formed soap berries as imbeds on top of CP soap.