Without Lye, it isn't really soap
Without Lye, it isn't really soap.
Sometimes I am asked if our all-natural homemade soap contains lye. My response is always "without lye, it isn't really soap". Some commercial "soaps" do not contain lye, so technically are not even soap. So, what is it?
Soap requires three main ingredients to be real soap: liquid, fat and lye. The liquid can be water, milk, tea, coffee or juice. the fat can be animal or vegetable; tallow (beef) and lard (pork) makes a nice hard soap and lathers great, oils like olive, coconut, and shortening make the soap a bit softer, but lathers great too.
Lye is a caustic, alkaline chemical that is useful for many purposes but also is hazardous causing burns your skin and clothes if it comes into contact with it. Modern soap makers are able to purchase lye (sodium hydroxide) at the hardware store, but in the olden days, homesteaders had to make the lye themselves. They burned certain hardwoods at a very high temperature to make white ashes. Water, mixed with a bit of baking soda, then was used to penetrate the ashes and remove the lye that they contained. When the ashes were filtered out, the water would hold enough lye for purposes such as dissolving the fat left on animal furs or mixing with other ingredients to make body soap.
So, how can we wash our bodies with something that can burn us? When you combine lye, liquid and fat, a process is triggered call saponification. This process changes the caustic lye into a safe product. The type of liquid and fat used will give you a different kind of soap. You are able to experiment with the type of ingredients, but not the amount. Making soap is like baking: you have a recipe with exact proportions and method. If you do not measure precisely and use the proper method of mixing and baking, your cake may fall, your pie crust be hard and crumbly or your bread may not rise. With soap, if you use too much lye, the saponification process may not complete and your soap could be too strong, causing a burn or at least a longer processing time. If you use too little lye and/or too much fat, your soap will be soft, even mushy and greasy to use. The best balance of ingredients will yield a perfect bar of soap, so exact measurements are very important. A lye calculator is necessary if you are going to experiment with different oils and liquids.
There are two methods of making soap: cold and hot. The cold method is a slower process. Start by adding the lye to the liquid and dissolve completely. Melt any solid fat/oil and mix with the liquid oils. When both the oils and the lye solution are the same temperature, add the oils to the lye liquid and mix until you reach a stage called trace. This can take a long time, hours if you are stirring by hand or just a few minutes if you use a wand blender. You will recognize the trace stage when you lift the mixer and the liquid dripping from the end makes a raised ribbon effect on the surface of the mixture. At this point you can add fragrance or essential oils and botanicals (herbs, flowers, etc.) if you wish. Then, pour the mixture into a prepared mould and tap lightly to remove bubbles. Cover the mould with plastic wrap and then wrap with a towel or blanket. With the Cold process, it is important that the mixture is well insulated for 24-48 hrs. Test the soap by feeling under the blanket or towel to see if the mould and contents are still warm. Allow it to cool completely and them remove from the mould. you can wear kitchen gloves to protect your hands if wish, but at this point saponification should be complete and the soap is safe. Cut the soap up if you wish and set the soap pieces on a cooling rack or cookie sheet lined with parchment paper. Allow the soap to cure; I usually wait 3-5 weeks but it is safe to use right away. The longer it cures, the harder it will get, the more it will foam and the longer it will last.
Hot processing is much faster but can be messy, smelly and a little scary...at least that was my experience, so I don't use that method often. The process is the same up to the trace stage. Then the mixture needs to be cooked. When it is cooked, it bubbles and foams and grows and if you do not have a pot big enough for the increase in volume it makes a mess. That is what happened to me. But, it makes soap very quickly as the cooking step causes the saponification action to work right away and the soap can be used as soon as it cools. it still takes a few hours to cool off, but the resulting soap is hard and suds great right away. The finished soap is not quite as smooth looking either, so for selling, I prefer to use the cold method.
Just a few notes on safety. When working with lye and the mixture before saponification, be sure to protect yourself and your work surface. Cover your countertop with newspapers or an old towel to catch any drips and do not touch the mixture with your bare hands when cleaning up. Wear gloves, long sleeves, safety glasses and a mask to cover your nose and mouth. As I mentioned above, lye is caustic and can burn you. Even the dust and fumes in the air when pouring out the lye crystals and mixing the ingredients can cause discomfort and damage your skin, eyes and lungs. NEVER add the liquid to the lye as it could cause an explosion; ALWAYS add the lye to the liquid, slowly and stir continuously until the crystals have dissolved. The liquid will heat up very quickly, shooting up to over 200 degrees in a few seconds. Using a meat or candy thermometer, cool the lye solution and heat up the oils to be about the same temperature before combining and start mixing right away. Clean up any spills right away and allow any towels or cloths used to set for at least 24 hours before handling with bare hands. Rinse bowls and utensils well before washing in warm, soapy water or run through the dishwasher. This may sound like a lot of precautions, but it is important for your safety.