Enough people have asked me how I make soap over the years that I suppose it deserves at least one article. I’m going to explain the cold process method, which involves doing less work at the beginning and then waiting a few weeks, because I guess we tend to be lazy, but also patient. Note: certain steps of the soapmaking process are DANGEROUS, and I don’t suggest you attempt it based on this piece of writing alone. Do your research or take a class.
Step 1: Mix the catalyst. This involves mixing appropriate amounts of water and lye. Add the water first and then the lye. We do this in a large HDPE (number 2 plastic) jug. Why? HDPE can stand the hot temperature generated, we prefer it shaken, not stirred, and the opening at top of the jug is easy to aim away from the face or other body parts as the caustic steam escapes. Now, leave the hot lye/water mix to sit for about an hour, which is the time it takes to fall within the optimal 100 to 110 degree temperature range. MIXING THE CATALYST IS ONE OF THE DANGEROUS PARTS. Set a timer for 45 minutes for the first temperature check.
Step 2. Mix and heat the base oils. At the time of writing, we have a big jug of pre-mixed base oils, so we skip this step. But when we first started out, we would scoop the coconut and palm oil into a big metal stockpot with gardening trowels and put it on medium-low heat to melt. It’s better to heat the oil slowly to avoid burning and creating weird smells. The coconut and palm need more heat than 110 degrees to melt, but we found that when we added the room temperature liquid olive oil to the mix, the temperature of the whole thing came right down to the sweet spot.
Step 3. Mix the essential oils. Mixing the essential oils doesn’t take very long. We usually put the essential oil mix into a mason jar with a lid because if they were ever to spill, our workshop would smell like that particular scent blend FOREVER. Like mixing the base oils, mixing the essential oils can be done in big batches ahead of time. We have a shelf full of mason jars with scent mixes. Why do it this way? It saves a little bit of time to make big batches of each step at once. Also, if you only have half an hour at a time to work, this is one of the ways you can break the process into manageable chunks.
Step 4. Line the molds. We use hand-build wooden molds that we line with freezer paper. We’ve looked into designing some sort of plastic or silicone break-away mold, but we haven’t found a good design that the soap won’t stick to. If we did, this would save a bit of garbage, as well as about 10 minutes of production time per loaf. But the added step of cleaning the molds might add those 10 minutes right back on. Lining the molds is yet another step that we often do in big batches ahead of time. Can you see a pattern?
Step 5. Make sure you have all the stuff set up for the pour. The final few steps of soapmaking are pretty hectic, as you have to mix and pour before the soap gets too thick. It helps to set up your space in a way that you can work quickly without making too much of a mess, ruining the loaf, or getting injured. For example, make sure you have a clear pathway from the mixing location to the soap mold(s). Make sure the soap mold(s) are sitting on a level surface. Line up the essential oil mix and any other added things so they are ready at the right moment.
Step 6. Drink a beer. After doing all these steps, there still might be some time left to wait before the catalyst is cool enough. Especially if you did some of the steps in big batches ahead of time. After the 45 min timer goes off, check the temperature of the catalyst. If it still isn’t cool enough, keep checking it every 15 minutes. Also, keep an eye on the base oils. It should be pretty obvious when they’re melted. Keep a close eye on them when they are almost melted, but still a bit cloudy. If you overhead the oils, it’s going to take a lot more waiting and a some more beer. You will probably also have to transfer the catalyst into another container to heat it up again, which is one more risky step dealing with lye. So just don’t overheat the oils.
Step 7. The final last hectic bit. At this point, the catalyst should be cool enough and the oil should be warm enough so that they are about the same temperature. Next, you pour the catalyst into the oil and blend with an immersion blender for about 10 or 15 seconds until that mysterious moment called “trace” when the mix begins to thicken just a little bit. (A whole blog post could be written on “trace” so I am going to leave it alone for now.) Then you add the essential oil mix, blend for a few more seconds, add the flowers, herbs, coffee grinds, or any other little bits and pour into the mold(s).
Step 8. Cutting and curing. After a couple days, the soap loaves can come out of the molds and you can cut them into individual bars. After a few weeks, the bars will be solid enough to withstand a few showers without turning immediately into goop. At this point they are ready to use. Celebrate by drinking a beer and taking a shower!