I am by no means an expert on this, and have only used it this one time, but I thought I would blog my observations for future.
When using fragrances that have a high vanilla content, they will discolor your soaps from a range of tan to a very dark brown. It is all dependent on the vanilla content percentage. Some fragrance oils have none to very little so you never notice a difference in color, but some fragrance oils, such as most bakery scents, have a high vanilla content.
There is a product called vanilla stabilizer. It is used to help rid your soap of brown discoloration. You can use it with fragrance oils that have more than 5% vanilla content. (You should be able to get this information from your supplier.) It won’t make your soap white, in fact I have read that it can yellow your soap if you have a real high vanilla content, but it is to reduce the browning of Melt & Pour and some Cold Process soaps caused by fragrances that contain vanilla. (It will not prevent color changes due to ingredients other than vanilla.)
In order to use it you would mix equal parts Vanilla Stabilizer and fragrance oil, mixing well, then add this to your soap mixture as you normally do. So say according to your recipe you are using 2.5 oz vanilla fragrance, you would also mix in 2.5 oz vanilla stabilizer.
For this illustration I soaped the same scent IFT-Vanilla Bean Noel. One batch I used only the fragrance, and the other batch I used equal parts fragrance and vanilla stabilizer. Quite a difference. Obviously the one on the right is the one without the stabilizer.
Personally, I don’t mind brown soap….well unless it creates brown bubbles and discolors my wash cloth…I just don’t find that appealing, but this dark brown vanilla soap of mine produces white bubbles, so to me I only care about the end result being a good safe bar of soap.
What are your thoughts, would brown color discourage you from purchasing? Is having extra additives in your soap worth it to have a lighter shade of brown?