Making a batch of homemade lye soap doesn't have to be complicated. I like making a simple lard-based soap to keep on hand. Homemade soap is reliably rich and full of natural glycerin that is stripped from commercial soaps. It is a good cleanser and gentle on your skin. I have friends who like to use it on skin affected by poison ivy and bug bites. Another friend likes to soap up before hunting to clear his skin of colognes or body odors that can be smelled by deer.
Caution should be taken through the entire process, because lye is a strong, caustic chemical that can quickly eat through skin and many other materials. I don't want to scare you, but please be careful whenever you handle lye! Everything that you choose to use in making lye soap must be labeled as such, and from that point on ONLY used for lye soap. Anything that has contained lye must never be used for food purposes ever again.
There are several things that must be on hand to make a batch of lye soap. You should have a glass jar for dissolving the lye in, a kitchen thermometer, a 2-quart (or bigger) bowl for mixing the soap, a scale for measuring the ingredients in ounces, a plastic or wooden stirrer for stirring the soap, and a mold for pouring the soap into. The mold can be any plastic container big enough for the batch; I like to use a plastic Velveeta storage container, it is a long rectangle that when unmolded the soap can be sliced into nice size bars. Lard, lye and vinegar are also necessary. Lye can sometimes be hard to find, I have been able to buy it at a local hardware store. Vinegar should be kept close through the entire process, as it is an acid that can quickly neutralize the alkaline lye.
For this recipe, you will simply need exactly 2 lbs of lard, 4.4 oz of lye, and 7 fluid oz water. The first step would be to accurately weigh the lard and lye using the scale, and the water using a liquid measuring cup. Then the lye must be mixed with the water. Dissolving the lye into the water requires some special preparation. You should do this outside if possible, or in a very well ventilated area inside. The lye should always be poured into the water, not vice-versa. Once the lye is poured into the water it heats the water quickly and intensely, so the jar should be placed on a solid surface where it can be left as it cools to the proper temperature. Care should also be taken that animals or children cannot get near the lye solution. While mixing the lye and water, wear a simple pair of safety glasses to protect your eyes. So, with all those precautions in mind, pour the lye crystals into the water while stirring with either a wooden or plastic spoon. Once completely dissolved you can leave it to cool.
While the lye is cooling, you can heat up the lard and get it to the proper temperature as well. When the lye solution is about 85 degrees Fahrenheit and you have your fat at about 90 degrees, mixing can take place. These temperatures are a general rule, if the fat is a bit warmer and the lye a tad cooler, it will still work out. While stirring the fat in your plastic bowl with a plastic or wooden spoon, slowly stream in the lye solution. Stir constantly until it is thick like a Slurpee. This will take from 30 minutes to one hour. Now you can add any essential oils for fragrance or leave it plain. Pour it into your mold scraping the sides of the bowl.
The emulsion created by combining the lye water and fat creates a chemical reaction called saponification. During this process of saponification the lye and fat create soap. After several days in the mold, the soap should be hard enough to pop out of it. This is when I go ahead and cut it into bars (with a knife or bench scraper) and lay them in a cardboard box lined with brown paper. The soap now must age for at least 4 weeks to complete the saponification process. To test the soap, try washing your hands with it, if it leaves a slimy film on your hands, rinse your hands with vinegar and let the soap cure another couple of weeks. A well-mixed, completely saponified soap has a long shelf life.
After you are through with your soap making equipment, wash everything thoroughly with hot soapy water and also rinse with a little vinegar to neutralize any traces of lye.
While this is a pure and simple soap, there are a multitude of options and some wonderful soap making resources available online if you are interested in trying other combinations. Almost any fat can be used, and each kind will add different characteristics to the soap. One I enjoy adding is coconut oil, which creates wonderful bubbles and suds. There are also great recipes for vegetarian soap made without any animal fats. Learning how to render your own fats is helpful for soap making (tallow from beef fat makes a beautiful white soap). Let me know if you enjoy soap making and share any tips or websites you find helpful!