Homemade Cold Pressed Vegetable Oil Soap
Homemade soap needs fat or oil. You can use animal fat or vegetable oil. In our case the vegetable oil is, as always olive oil, as that is the one oil we are self sufficient in. So far we have only made 100% olive oil homemade soap (Castille soap) but other oils could be added. Coconut oil would be a particularly good oil to include in your homemade soap. In moderation it would improve the lathering qualities of this homemade olive oil soap.
If you are new to soap-making I highly recommend trying the 100% olive oil soap. It is straightforward and doesn’t mean sourcing lots of ingredients. It certainly gave me the soap making bug!
Soap making at home can be as basic or as complicated as you like. If you would like to find out how to make a decent and simple homemade olive oil soap please read on. If however, you’re after something very pretty and scented this might not the place for you. Well not until I have made a lot more anyway.
Basic, though this Castile soap recipe may be, it is also a great place to start if you have never made soap before. The end result is a very hard bar of moisturising soap. The lather is not as ‘bubbly’ as you might be used to but it does all the things soap should do!
All oils need different amounts of lye to turn them into soap safely. So if you want to add other oils to the soap or use different quantities you must re-calculate the amount of lye needed. There are lots of free on-line lye calculators. I use this Brambleberry one as it is easy to use and quick.
How is Soap Made?
In very basic terms coldpressed soap is made by adding an alkali (base) which will be lye (caustic soda) to a fatty acid (olive oil).
A process called saponification occurs which stabilises the lye and solidifies the oil, creating, lathering capabilities. There is loads more to it but we don’t need to know all the chemistry to make soap at home.
When making soap at home we can see saponification start as the mixture begins to ‘trace‘. All that means is that the mixture will thicken and the surface become almost ripply. The path of your spoon will leave a ‘trace’ across the surface of the mixture.
Saponification will continue after the soap is poured into moulds. The mixture will warm, liquefy and cool repeatedly during this process so make sure you do not handle it for at least 12 hours or until the mixture has cooled completely.
How to Make Homemade Castile Soap
First of all, you will be working with lye which is extremely corrosive so clear yourself some room, protect everything and be careful! Goggles, gloves and no pets would be the ideal scenario.
Utensils for Soap Making
All pans, bowls and moulds used should be non-corrosive (definitely no aluminium) and ideally assigned for soap making duty only. If not they will need very careful cleaning before using for anything else.
Wooden spoons are suitable for soap making but will be degraded by the lye so definitely keep one solely for use in soap making and nothing else.
Moulds can be any plastic or glass (more difficult to unmould though, trust me) kitchen containers or wooden soap moulds. Just make sure they have a cover or make one from cardboard.
To make unmoulding easier you could grease the mould and line with greaseproof paper. Or pop the mould in the deep freeze for a few hours to allow the soap to shrink away from the sides of the container.
Homemade Castile Soap Ingredients
In soap making, things must all be measured by weight not volume. For our starter Castile soap recipe we use:
- 30 oz olive oil
- 3.8 oz lye
- 10 oz water
If you want to make a larger or smaller batch recalculate the amount of lye required using the Brambleberry Lye Calculator.
Homemade Castile Soap Recipe
- Firstly make your lye water by slowly adding the caustic soda to the cold water. This may get hot and bubbly and give off fumes so take care. Leave to cool.
- Heat the olive oil in a non-corrosive pan. Allow to cool to 100ºF. If you don’t have a thermometer just leave till the outside of the pan feels warm to the touch.
- Slowly add your lye water to the warm oil, stirring all the time. Once all the lye water has been added to the oil the mixture should be well amalgamated.
- Now keep stirring. You will need to stir from between 10 minutes and an hour. You can use mechanical help but have to be careful not to over mix so keep any blender action to short bursts. I’ve always found stirring by hand pretty therapeutic so just put on some music and stir with a wooden spoon – we find about 25 minutes tends to do it. The finished mixture will be thick and rippled looking.
- Pour the homemade soap into prepared moulds. Cover and leave somewhere warm or wrapped in a towel for at least 12 hours.
- The next day (or at least within a week), unmould and cut the soap while it is still relatively soft.
- Leave your finished homemade castile soap to ‘cure’ for four weeks wrapped in tissue or card on a well-ventilated shelf.
As the homemade soap cures, water content is lost, the Castile soap hardens, and the lye becomes inactive. If you are unsure of the soap’s qualities you can always test with a ph kit or litmus paper. Soap should ideally have a ph of 7 – 9.5. If it is any higher the soap may still be used for laundry but not on the skin.
Olive oil soap cures into a very hard soap so make sure you cut it sooner rather than later as it gets quite brittle. You can see below I left this batch a little too long before cutting.
Using Homemade Lye from Wood Ash
You can of course use homemade lye from wood ash to make your homemade soaps. But, it is far more difficult to gauge the quantities to use as it depends on the strength of the lye. We used 6oz homemade lye water for 16oz olive oil, but it really is different every time.
Generally homemade lye is used for making liquid soaps. But you can make hard soaps by adding salt. For every pound of oil in the soap recipe add 1/2 tsp of salt to the lye water.
Homemade Liquid Olive Oil Soap
We have made liquid soap using homemade lye from wood ash. The method is the same but no additional water is needed. Just add the homemade lye-water to warm olive oil. I make no guarantee of this working though as you need to ensure your lye-water is of the correct strength!
If you are in the mood for some soap making at home then it is worth having a go. I’ve found the homemade liquid olive oil soap using homemade lye from wood ash is really thick and creamy. It actually works better mixed up with water in a squirty handwash bottle. It is possibly good shampoo material but I’ve yet to decide 100%!
I hope I’ve inspired you to have a go at making your own homemade soap. It is suprisingly simple and the possibilities for creating your own recipes are endless. I think I know what everyone I know is having for Chrimbo this year!
For a more self sufficient future