Soaping is a process where you combine oils and butters with a strong alkali to create a reaction that changes the oils into a new saponified version that has cleaning power. The alkali used is lye, aka; sodium hydroxide for hard soap and potassium hydroxide for liquid soap. Soap is now the water-soluble salt of a fatty acid. Too much technicality perhaps…
Making soap has been around for thousands of years. There is an existing Roman legend that explains the name. Animals were sacrificed on Mount Sapo, where the rain would wash the fat from the animals over the alkaline wood ashes into the river. The people washing clothes in the river found it beneficial to clean clothes.
Perhaps if I had seen that amazing reaction in my high school chemistry class I would have paid more attention, and at times now, I wish I had a degree in chemistry! I do warn you though, once you try making soap, it has a way of hooking you and you become a “soap addict”!
As I said, there is a strong alkali involved! LYE! Do be careful and respectful of it! Don’t even ask what lye can do to a body! The whole idea is to have the lye completely react with the oils, and if anything, let there be “extra” fats/oils after the reaction is done, rather than extra lye. That “extra” oil is called super fatting. That fat will be similar to applying a lotion, and also depends on the type of oil or fat. Each oil has a certain qualities for skin and soap. See here and here.
Now, don’t be afraid if this is sounding very complicated. You DON’T need to be a chemical engineer at all. There are aids to calculating how much of each of the oil you would like to use to give you a good soap. I always use this calculator. It lets me fill in the amounts by either percentage or weight, and how much super-fatting I’d like. It will then give you the rating of the recipe in various categories. Like I said, I’m not an engineer. I try small batches when I have concocted an acceptable recipe and I also test my soap by doing lots of hand washing. The best recipes are usually a combination of hard fats and soft/liquid oils to the lye that is dissolved in some water based liquid.
Here is a basic laundry bar recipe. You quickly will learn that coconut oil in soap makes it very bubbly and also very cleansing. For that reason I have it at 50% of the fats, since I want this to be for cleansing. The other fat is the beef tallow. (which you can render yourself as in my tutorial)
For safety, you need protective equipment: Gloves, eye protection, long sleeves in case of splashes, apron etc. All the ingredients are measured by weight, so you need a good digital scale, stirring utensils, bowls and vessels for measuring/mixing.
DO NOT use anything that is aluminum, as it will react with the lye! I like the permanence of glass and a good metal stick blender.
- 12 ounces coconut oil
- 12 ounces beef tallow
- 8.4 ounces of water (weighed)
- 3.9 ounces lye
- fragrance or essential oil of choice
(I added a bit of Limonene)
First gather all your ingredients. Once the lye is added slowly to the water the reaction will heat it up so I use a container of ice to keep it cool. Measuring is in 2 parts. One is the oils, measured and liquefied, and the other is combining the lye with the water (in this case). See my other recipes for using milk as the the liquid.
The temperatures are somewhat important. It is best if the oils and the lye water are roughly the same. The lye here is around 100 degrees.
The oils need some heat to melt the tallow and coconut oil. Short bursts in the microwave will melt the tallow and coconut oil. To save on cleaning I add to the same bowl and reset scale to zero in between measurements.
Once I am have both ready, I need my stick blender. I pour the lye water into the oils carefully, and start to stir.
The reaction is starting to take place, but will depend on the ingredients. This combination has a reaction that is pretty quick. You will see it thicken and emulsify with the use of the stick blender.
Once you see it starting to resemble pudding, it is what the soapers call “trace”. Trace is when it leaves a trail in the mixture. I make sure I have to mold ready when I start as I don’t want to be caught off guard. Depending on certain factors, it may get thick too quickly.
I like to stir for the last bit to rid it of air bubbles, and incorporate the fragrance or essential oils. Then pour into the mold. I use a cheap “tupperware type” mold that has some flexibility and simple sides. I line it with parchment paper.
As it gets thicker, you can have fun sculpting the tops like icing on a cake. NO LICKING THOUGH!!! This is a laundry bar, but when using other recipes you can color portions to swirl etc.
Clean up is the worst part, I’ll admit. You definitely want to keep gloves on! I like to get all the goop off everything as much as possible via paper towels that go to trash. Then the amount of greasiness for washing and drains is lessened.
You now have the choice to “insulate” (wrapping in a blanket or such) to let the heat “gel” the soap or prevent heating by popping into fridge. In summer I find it hard to prevent any gelling so I let it gel by covering lightly with a blanket. This is a hard bar, so don’t wait to long to cut. It can be cut once it is hard and sturdy enough, which means it has done it’s chemical reaction. It’s always exciting to cut, such a large block of waxy , shiny, chemical magic!