Soap! Soap is a corner stone of our modern, civilized and above all clean society. It is cheap and readily available It helps prevent a range of hideousness skin complaints. It helps keep our bodies looking spry and fresh. Well, as best they can. It helps to keep our hands sanitized, so we can eat with our fingers and not pick up the conditions that physicians regard as 'interesting'. It achieves all this and yet it is cheap and readily available.
To make it requires mixing some form of fat with caustic soda, in just the right ratio. If there is too much fat the result will be an oily mess, too much caustic soda and you have drain cleaner. This will work to clean your skin, but it will also remove a lot of it in the process, resulting in hideous scarring and a stay in hospital. Given the potential side effects of making soap and its cheapness and availability, you might ask what kind of a fool would make their own soap?
I first made my own soap a year ago. Tired of commercial soap that seemed to be leaving my skin as a dry and crumbly husk, I decided to look for another option. The most obvious choice would be to pay a little more to get a higher quality soap. I chose not to spend the money. I chose something else.
In part this was so that I could put tea tree oil into the soap, to have all of that anti-bacterial and anti-fungal goodness in a natural way. In part it was also due to same old curiosity that gets me into all of these things.
As is the modern way, to find out more I consulted the internet. It turns out that soap is formed through a chemical reaction between fat and caustic soda, known as Saponification. Through the magic of chemistry soap is formed. As this is a chemical reaction, the chemicals need to be in just the right ratio, otherwise there will be some left over. Apparently in the industrial process of soap making they put in an excess of caustic, so that all of the fat turns to soap, then they engage in a few more steps of chemical wizardry to remove the excess caustic to leave only soap. This is way too much effort and bother for home soap making and so most people put in 5 -10% excess fat, to make sure all of the caustic is gone before it get to their skin.
Hopefully by now you have worked out that soap making is not a risk free process. If you are a chemist, about now you will probably give a derisory snort about the trifling dangers of caustic. If not you may be squealing because caustic could damage your beautiful skin. So I should say don't try this at home. I don't want to held responsible for people getting caustic burns. If you still insist on making soap, make sure you use take care and use the correct protection (clothes, goggles and gloves that can resist caustic).
To make soap it is important to get the ratios of the fats that you are using and the caustic right. I may have mentioned this already. Different types of fat need different amounts of caustic to make soap, because of the length of the molecules. The actual calculation for the ratios of fats to caustic is too long and boring to detail here, but the easiest way to calculate it is to get someone else to do it for you. Thanks to the internet, this little bit of outsourcing is easy and free. There are several 'saponification calculators' out there on the internet. Just google it.
Different types of fat will have different effects on the resulting soap. Some will make it mere bubbly, while others will make it harder, some can have a drying effect on the skin. Again this information is out there on the internet and there are hundreds of types of fat that can be used, so I will not try to detail them here.
My first attempt at making soap, I chose to use olive oil as my only type of fat. I had experienced and become rather fond of olive soap on a trip to Syria a few years ago. However in this part of the world it seems to change hands at a price more associated with speculative trading of commodities. To its fans olive soap is soft and creamy. To its detractor it is slimy and doesn't bubble. To the people who make it, it is a slow process.
There are several methods that can be used to make soap, most notably the hot process and the cold process. The hot process, as you might expect, is hot, but the cold process is not cold, it is just not as hot as the hot one. most people who make soap at home opt for the cold process. This involves dissolving the caustic in water (in a well ventilated area), which will automatically heat up, and melting/ heating the fats, then combining them at about 40 degrees C. Once they are combined, stir until they thicken, known as the 'trace' point.
The time it takes to reach trace can vary according to what fats are being used. I had read that olive oil can take a long time to reach trace, but I was still surprised when I was still stirring an hour later. I then resorted to using a hand held blender and when it reached trace, I wan't sure if I had just emulsified the mixture or not.
Once trace is reached, other smelly oils can be added, in my case tea tree oil, and the mixture is poured into molds. It takes a few days to harden to the point where it can be turned out of the molds. Then it should be left in an airing cupboard for six weeks, to make sure the reaction has finished and there is no caustic left in there.
After my first foray into soap making, I became more adventurous and used a combination of bees wax, olive oil and coconut butter as the fat. This has the advantage that it reaches trace almost instantly. In fact the first time I made it I thought the wax had set when I poured in the slightly cooler caustic solution.
45g Coconut oil
225g Pomace olive oil
114g (=114ml) Water
38g Caustic soda
It produces a soap that is creamy and pleasant. I have been using almost nothing else in the shower or bath for the last year, and I still have skin. The ingredients are cheap, and in my house at least this soap is readily available.