
I’ve promised myself for years that I’d learn to make my own soap, but I never got around to it. I finally got my act together, rounded up all the equipment and materials I needed, and started my first-ever batch of soap over Labor Day weekend. I unwrapped a bar a couple of weeks ago and can confirm that it is, in fact, lovely stuff. Homemade castile soap makes a nice Christmas present, and if you start a batch now, it should have time to age before Dec. 25.
Details are below the fold.
I used a basic castile soap recipe from Miller’s Homemade Soap, which is a great resource. I also consulted Mother Earth News.
Equipment you need:
Kitchen scale (the digital ones are awesome)
5-gallon bucket
Stick blender
Pyrex measuring cup
Loaf pan, shoebox or similar container
Cooler
Chef’s knife
Waxed paper
Chopstick or similar disposable utensil
Candy thermometer you aren’t planning to use for anything else
Rubber gloves
Dust mask
Safety goggles
Shotglass
Ingredients:
I started with Kathy Miller’s “Favorite Castile/No Palm Oil” recipe and added my favorite essential oils at trace.
12 oz. lye crystals (by weight, not volume, and DO NOT use Drano or Red Devil, as they contain additional chemicals that will ruin your soap)
74 oz. olive oil (by weight, not by volume)
14 oz. coconut oil (also by weight)
24 oz. cold water (by volume)
Your favorite essential oil (optional; I used cedar and patchouli, but pine and peppermint would be nice for Christmas)
Put on rubber gloves, goggles and a dust mask to protect yourself while you’re handling the lye. (Some soapmakers will say this is unnecessary, but I’m a klutz, so I wasn’t taking any chances.) Measure out the lye crystals and water and carefully stir the lye into the water with a chopstick or other disposable utensil. It will release a lot of fumes. Don’t breathe them, and make sure your workspace is well-ventilated.
Put the olive and coconut oils in a large microwavable bowl and nuke until the coconut oil melts. Let the lye and oil sit until they’re both between 90 and 100 degrees. While you wait for them to cool down, half-fill a shotglass with your favorite essential oil(s).
Line a couple of reusable plastic food storage containers, a big loaf pan or a smallish shoebox with waxed paper to use as a mold. Make sure whatever you use as a mold will fit inside your cooler.
Pour the olive oil mixture into your five-gallon bucket. Carefully add the lye and stir it in with the stick blender shut off. (You always want to pour the lye into the oil, and not the other way around.) Submerge the blender, turn it on, and stir the mixture until it “traces,” which should take about five minutes. “Trace” is a soapmaking term that basically means it’s thickened up to the texture of a proper cream gravy. If it looks thinner than something you’d pour over chicken-fried steak and biscuits, keep stirring.
Once it traces, stir in the essential oil and pour the soap into your mold(s). Put the molds in the cooler and leave them alone overnight.

In the morning, put your rubber gloves back on, unmold your soap and cut it into bars. Wrap the bars in waxed paper, stash them in a cool spot, and ignore them for five to six weeks.
That last step is important, because while the soap may look finished when you unmold it, trust me: It isn’t, and if you try to use it now, you could end up with chemical burns. After being mixed together, the lye and fat have to undergo a chemical process called saponification, which means they turn into soap as they age. For castile soap, this process takes five to six weeks.
Once your soap has aged at least five weeks, get out a bar, cut off a small slice, and wash your hands with it. If it seems gooey or squishy, let it age some more. If it feels firm, it’s ready.
Happy soapmaking!
Emily