5. Soap is a sodium salt - the same kind of salt you put on your food (in theory!
6. Soap is a surfactant - that means it dissolves in both water and oil - this is why you can rinse oil off your hands with soap. Hot water not necessary but it does make the job a little easier.
7. You can use saturated or unsaturated fats to make soap - saturated fats ie coconut oil will make a harder soap, while unsaturated ie olive oil will make it softer, on that point most solid fats are saturated, whilst most liquid oils are unsaturated.
8. The final PH of your soap varies depending upon the type of fatty acids in your chosen fats and oils. As a guide, it can be between 10.1 and 11.4.
9. It is possible to reduce the PH of your soap even further with hot process soap making by adding a low PH fatty acid or even something like citric acid to your soap after the cook and before you put it in the mold.
10. The final composition of the superfat in your cold processed bar of soap will depend on the makeup of your recipe. Those ingredients that react with lye the slowest will make up the biggest proportion of your superfat. To put this into perspective, if you were to make a very simple coconut oil/olive oil soap at a 50/50 ratio of each you might expect the super fat to be 50/50 too but because the unsaturated oils in olive oil are slower to react with lye than the saturated fats in coconut oil so you will have a higher proportion of olive oil in your finished bar.