- Using a digital scale, measure out your water and pour it into a heat-resistant glass. This is important because when you add in the lye, it will get very hot very quickly.
- Measure out the lye and add it to the water. Stir the lye until it dissolves. Note, the chemical reaction will cause it to heat up quickly.
- Measure out the tallow and coconut oil, add to a saucepan. Melt over medium heat.
- Once the ingredients are melted, allow them to cool back down to 37.7°C. This may take a couple of hour.
- Once the fats reach 37.7°C, it is time to mix the lye water with the oils. Slowly add the lye and water to the oils and mix with an immersion blender. This will take a couple of minutes. You will know it is the right consistency when the soap from the blender drips and pools up on top of the soap in the saucepan. This is known as the trace.
- If using essential oils or color, add those in now. Stir well.
- Allow the soap to harden and sit in the molds for at least 24 hours or up to 3 days.
- Remove the soap from the molds and allow it to cure for 3-4 weeks before using.
It is important to handle lye with caution. Ensure that you wear protective goggles and gloves, and also work in an area with adequate ventilation.