Gather ingredients: surfactant base, oils or butters, water or hydrosol, humectant, conditioner, preservative if needed, fragrance or essential oil, colorant if desired
Measure all ingredients by weight
Melt the oils and butters if using them
Combine the surfactant base with the melted oils and other dry ingredients
Add the liquid ingredients slowly and mix until a dough-like consistency forms
Add fragrance, essential oils, and colorants
Mix thoroughly until the mixture is uniform
Press the mixture firmly into molds
Smooth the tops and compact the bars well
Let the bars harden and dry completely
Unmold the bars after they are firm
Cure or air-dry the bars as needed
Store the finished bars in a dry place
Use a soap dish or draining tray to keep bars dry between uses