How to Mill Soap at Home

Put on safety goggles and rubber gloves before you begin working with lye. You must protect yourself throughout the process.

Measure out 6 parts distilled water, 2-1/4 parts lye, 6 parts coconut oil and 10 parts olive oil into separate glass cups. Measure them by volume on a food scale to ensure you have the correct proportions. Measure 1 tbsp. of castor oil into a fifth cup.

Pour the distilled water into a large glass bowl with a pour spout. The spout makes it easier to pour the soap into molds later.

Pour the lye into the distilled water, stirring it constantly. The mixture will begin to steam and fume; keep a window open and stand back from the mixture as you stir. Let the mixture cool and settle for about an hour.

Mix all of the oils together and heat them in the microwave for about 45 seconds. Coconut oil is solid at room temperature but melts very quickly. When the coconut oil melts completely, test the temperature with a thermometer. It should be approximately 109 degrees Fahrenheit.

Pour the melted oils into a second large glass bowl with a pour spout. While stirring with the whisk, pour the lye and water solution into the oil solution. Continue to whisk until the mixture resembles thick, heavy cream.

Spray your soap molds with cooking spray and wipe away the excess with a paper towel. This keeps the soap from sticking to the mold.

Fill each of the molds with soap and cover them with plastic wrap. Let the soap harden overnight then pop the soap bars free.