Gather oils/fats, lye, distilled water, a heat-safe container, a scale, a thermometer, a stick blender, molds, and safety gear
Put on gloves and eye protection
Measure all ingredients by weight
Slowly add lye to water, never water to lye
Stir until the lye fully dissolves
Let the lye solution cool to the target temperature
Melt and combine the oils/fats
Bring the oils and lye solution to similar temperatures
Pour the lye solution into the oils
Blend until the mixture reaches trace
Add fragrance, color, or additives if desired
Pour the soap batter into molds
Tap the molds to release air bubbles
Cover and let the soap set for 24 to 48 hours
Unmold the soap
Cut the soap into bars if needed
Cure the bars in a ventilated area for 4 to 6 weeks
Store the finished soap in a dry place