We've been busy testing lots of potential new fragrances in cold process soap, and I came across a yummy scent called Vanilla Hazelnut that I made in a four pound batch. Here's the thing, vanilla is the main ingredient so I know it is going to turn brown over time. This is true for most dessert -type fragrances because they generally contain vanilla.
To battle discoloration, you can add some titanium dioxide to lighten your soap. If you are swirling, it works even better to leave the scent out of just the titanium dioxide part for more of a true white color. Then swirl it in with the scented/colored soap so you at least get some contrast. Here's my creation after 24 hours:
I split my batch at a very light trace into three containers, one for each of the following colors:
1. About 1/2 teaspoon of Titanium Dioxide
2. About 1/4 teaspoon Brick Red Oxide blended with 1/4 teaspoon Copper Sparkle Mica
3. About 1/4 teaspoon Cappuccino Mica
Start stick blending your lightest color first so that you are not dipping any dark brown into your white. Hand stir the fragrance into each container of raw soap at the very end to keep the consistency nice and thin. When we test a new fragrance, we don't know if it could suddenly act up in our cold process batch and acceleration trace, so we add scent at the end.
Now for the fun part! Start pouring each color into your lined mold in a spontaneous manner. It does not have to be perfect. I start with white and then go across in an "S" pattern with one of my colors, then pour another strip of white, and alternate the "S" pattern again with another color until the mold is full. The most important tool you will need for finishing your swirl is a rubber spatula. Make sure it touches the bottom of your mold and create a figure-eight pattern from one end to the other without lifting the spatula. Done! Now, let's see how well the colors hold up at the end of the curing time in four weeks. I expect the white to end up at a medium to light tan color.