Prepare your mold: If you are using a wood mold it will need to be lined with wax paper. Silicone molds are ready without any special preparation. You can also use any box if you line it with wax paper or a thick garbage bag.
Wearing protective gear, place the glass jar on the scale, and tare the scale.
Pour distilled water into the jar until it reads 10.9 oz.
Put the second jar on the scale and tare the scale. Wearing protective gear, carefully pour the lye into the jar until the scale reads 4.39 oz.
Take both jars and a spoon outside.
Still wearing protective gear, slowly pour the lye into the water.
Stir the mixture. It will become quite hot so keep this in mind if you need to move it.
Let the water/lye mixture sit and cool until it reaches about 100°F.
While the lye is cooling, measure all other ingredients EXCEPT the essential oils and warm them together in a pot or slow-cooker. The beeswax will take the longest to melt.
Once everything is melted, remove the pan from the heat and let it cool to 100°F. I use the infrared thermometer about every 5-10 minutes to test the temperature, which works really well. A candy thermometer placed in each container also works. If one is cooling faster than the other you can put your oils back on the heat source or the water/lye mixture in a warm water bath to slow the cooling process a bit. Ideally, you want the lye-water and the oils to both be within 10°F of each other and around 100°F.
When the temperatures match, slowly pour the lye-water into the oils.
Use the immersion blender to bring the batter to a light trace. It should be slightly thick and resemble cake batter.
If you are adding essential oils now is the time to do so.
Blend essential oils in by pulsing the immersion blender a few times. This should bring the mixture to a medium trace. You can tell when you have reached a medium trace by lifting your blender up out of the mixture (in the OFF position) and observing how the drips behave. They should sit on the surface without sinking back in.
Pour the soap batter into your prepared mold. Remember that the soap is not fully “cooked” yet at this point and could still irritate your skin so you should still be wearing your gear.
Place an upside-down cardboard box over the soap and cover it with a towel. If you live in a warm climate the towel may not be necessary.
Let sit for 24 hours.
Un-mold your soap and cut it.
Stand bars up in a dry area with an inch or so of space in between to allow for air circulation and let them sit for 4-6 weeks. This will allow the soap to complete the saponification process and also dry them out a bit so they last longer in the shower.
All quantities are measured in ounces by weight. This recipe makes 3 pounds of soap -- about 10 (4.5oz) bars.