So, last week I made soap!
Cold process soap making is basically creating a lye solution and mixing it with oil to form soap. Because the process involves lye (sodium hydroxide - NaOH) there are some significant safety precautions that need to be taken. Nothing that can't be handled at home, but you do need (no joke) safety glasses and gloves at a minimum. I started learning by reading at the Miller soap website.
For my first try, I wanted a fairly simple recipe. I also wanted it to be made from oils that I either already had on hand or could purchase inexpensively. I settled on a shampoo bar recipe that used coconut oil, castor oil, and sunflower oil. For safety reasons, you should always be sure to run any soap recipe through a lye calculator before making it.
I gathered up my supplies: lab glasses and apron (leftover from my science teacher days), an old pair of rubber kitchen gloves, my digital kitchen scale, an old plastic pitcher, old stainless steel saucepan, and some old plastic spoons. When soap making, it is important to use only non-reactive containers and utensils: glass, heavy plastic, stainless steel, or unchipped enamelware. I purchased my lye from a local hardware, where I found it with the drain cleaners. You have to be careful to find a product that is 100% lye -- I used Roebic.
Because I have an active, inquisitive, and erraticly napping toddler, I wanted to wait until DH was home before trying this. The last thing I want is for The Boy to wake up enexpectedly, just as I've mixed up a pitcher of lye solution! For this reason, I'll be soap making only when The Boy is at preschool or during weekend naps when DH is also home. If you would like to try cold process soap making, be sure to consider safety issues such as this before you start. You will also need a safe, pet and child proof area to store your lye solution as it is cooling and the soap as it cures.
Once all of my materials were assembled, the actual soap making went very quickly. It took me about one hour from start to finish, including clean-up. I started by adding my solid lye to strong, cold rosemary tea. Lye is always added to water (or tea or milk, or other liquid), never the other way around. The lye solution heats up very quickly and produces fumes. I mixed mine outside since it was cold and better ventilated than my kitchen. I then waited for the lye solution to cool down.
Meanwhile, I measured out my solid oils (coconut) and started to melt them carefully. Once they were melted, I added the liquid oils (castor and sunflower). When the oil mixture and the lye mixture were at approximately the same temperature, I added the lye mixture to the oil mixture, while stirring carefully.
Once the oils and lye were mixed, I stirred the mixture until they reached "trace." Trace is a soap making term -- basically it it the point at which your mixture has begun the chemical reaction into soap. You can see it has happened when the oil and lye mixture has thickened enough that dribbling it on the surface leaves a "trace" on the surface.
I cut my soap into bars two days later. It is now curing in the basement on some of the wire shelves we use to store squash and pumpkins. It should be ready to use in about 4 - 6 weeks. I'll be sure to update once we've had a chance to try it!
If you are considering soap making, please take some time to read up on the safety concerns before you get started. The Miller's Soap page is an excellent resource to start learning.