Still warm, your bacon fat should now look uniform, clear, and junk-free. Measure your bacon fat, then calculate the proper amount of lye — 1 part lye to 7½ parts bacon fat.
Measure 2 parts purified water. Feel free to include some ice in it, as the lye will get very hot. In a heat-resistant, nonmetal container, pour in your 2 parts water, then slowly pour the crystalline lye into the water.
Lye fumes are noxious and can cause serious injury. Make sure to wear rubber gloves and eye protection when handling lye, and to mix it in a well-ventilated area. Also, the lye and water mixture will get very hot, so be sure to mix them in a proper workspace, and in a heat-resistant nonmetal container.
Take a break and wait for the lye-water mixture to cool down. Do not leave the lye mixture unattended. When the lye-water mixture is around 100°F (the temperature of a hot shower), check your bacon fat and see if it is around the same temperature (if not, heat it on the stove until it is).
Then slowly pour the warm lye mixture into the warm bacon fat.
Stir the mixture for up to 2 hours as it cools. When the mixture begins to show “trace” (white soap stripes on the top surface), move on to the next step.
Mixing can take several hours. If your mixture is still liquid after 2 hours, move on to the next step and hope for the best.
Step #4: Make it look and smell like the real thing.
While the proto-soap mixture is still a thick liquid, but showing signs of trace, you can mix in liquid smoke flavoring as a fragrance to enhance the bacon smell.
Also, if you want to make your bacon soap look like bacon, now’s the time to pour a small portion of the mixture into a separate container and add a bit of red dye.
Pour the beige, thick proto-soap into a pyrex glass pan, then take the red-dyed proto-soap and pour stripes into it to make it look like bacon.
Let the soap set or “cure” for at least 36 hours, then cut blocks into desired shapes from the greater slab. Do this while it’s still relatively soft. Allow the soap to continue to cure for at least 2 weeks.