So after explaining how soap works and why washing in water alone will only remove some things from your clothes or yourself, lets look at how to make soap.
Soap is made from a chemical process called saponification.
Oil plus alkali becomes soap.
Depending on the type of oil an alkali used and how they are processed determines the type of soap produced.
The types of alkali
potassium (potash): these soaps tend to be liquid. Bracken ash
Sodium common soft soap. normal wood ash
calcium very hard soap. does not dissolve easily. mineral lime
the types of oils commonly used to make soap
This chart tells you how much alkali to add for each unit weight of fat/oil.
So for Almond, Sweet oil you will need 0.136 grams of NaOH per gram of this Oil to make soap.
If you are using multiple oils do the same calculation for each oil as though it were a separate soap and then add up all the alkali needed and add to final mixture.
The specific gravity is the density of this Oil relative to water (water = 1.000) hence anything less dense than water will float on water as almost all of these oils will do.
During the process of soap making you will either have too much oil or too much alkali.
Too much oil will make the soap greasy and too much alkali will be very harsh on the skin or material washed.
It generally better to have too much oil slightly as a bit greasy is better than very corrosive.
If you can do the numbers have 4-10% less lye than oil for optimal results.
Glycerine is a component of fatty acids and as the soap is produced the glycerine is produced.
too much glycerine will make the soap prone to converting to mush after its been left wet.
Try to experiment with removing the glycerine as the soap is made to get the right balance.
measure out quantities carefully.
Lye will get hot as you make it from Sodium hydroxide granules a shatter proof glass container is a good idea.
Heat the oil/fat until it is liquid and about 50C-60C and a similar temperature to the lye solution.
mix in an appropriate container, plastic containers are good, don’t use aluminum pots as they will react with the lye.
use blender to mix. 5-6 minutes should be enough.
pour into tray or muffin molds to set.
cover witha towel to keep the soap warm as it sets.
After 24 hours take the soap out of the molds and leave them is a dry warm place to dry fully.
leave the bars to store for a few weeks to fully react all the lye.
test soap with pH strips or pool water pH kit
Technically oils are acidic and saponification is an acid base reaction and the soap is the ‘salt’ of that reaction
Disturbingly enough during world war I, some bodies left covered in lime became saponified and became soap from the action of the lime on the body fat.
Lye in form of Sodium hydroxide (NaOH) can be purchased from some supermarkets as high purity beads in a small container. The high purity is useful in the very well measured cold soap making process, as you will need to measure everything carefully.
Sodium hydroxide is normally used for clearing blocked drains, usually the drains are blocked with hair, soap scum, scale and fat, and int he case of fat the lye solution turns it to soap similar to the way we have just learned.
<more to come>
An excel based calculator for soap making
Basic rule of thumb:
1 part alkali ( by weight as a dry powder)
8 parts oil (by weight)
24 parts water (by weight)
Warming up the oil to the same temperature as the alkali (which will usually heat the water used to create it).
Soaps created from types of hydroxides
Sodium: a solid water soluble soap.
Potassium: a liquid water soluble soap.
Calcium: a solid mostly insoluble soap.
Lithium: a grease possibly with lubrication potential for machines.