Cover the work area and put on gloves and protective equipment. Measure the water into a heat-safe jar, then slowly add the measured lye to the water while stirring. Avoid the fumes and allow the solution to cool.

Combine the three oils and warm them to about 120°F. Allow both the oils and lye solution to cool to between 95°F and 105°F.

Pour the oils into a mixing bowl. Slowly add the lye solution and stir by hand for about 5 minutes, then continue stirring or use an immersion blender until the mixture reaches trace.

Add any desired herbs, essential oils or other additions and mix thoroughly.

Pour into molds, cover, and insulate with an old towel. After about 24 hours, check the soap; if still warm or soft, leave it another 12–24 hours.

Unmold when cold and firm, cut into bars if needed, and cure for about 4 weeks, turning periodically so all sides are exposed to air.

When fully cured, wrap in wax paper or store appropriately. Clean lye-exposed equipment carefully.