Helen Prout shows us how to make castile soap from scratch
Soap making, once you’ve gotten your first loaf or two out of the way, is a relatively straight forward affair. There are a few steps that must be mastered first – once you’ve gotten the hang of these, more advanced techniques, involving various colours; design technique; scent and range of ingredients may be attempted.
For your first few soaps though, a simple recipe, with just a few ingredients, is best, as it allows you to become familiar with the basic soap-making techniques. Normally, these will involve just a mixture of one or two oils, no scent or colour. Typical examples of these are Castile soap bars and also laundry soap. Once these soaps have been mastered, then more advanced techniques can be attempted.
A word on safety – soap making involves the mixing of a strong alkaline (lye) with an acid (oils). The lye is extremely caustic in its liquid state, and can cause burns on contact. For this reason, precautions need to be taken when there are other people, especially children or animals in the house. Goggles and gloves must be worn whilst soaps are being mixed and poured. If there are others in the house, then as well as keeping them away during the soap making process, consider using cling film to cover freshly made soaps – to keep curious fingers away. If you should get lye on your skin, wash the area under running water for 15 minutes (seek medical attention if required); lye on worktops can quickly be neutralised using vinegar.
Once the lye and oils are mixed, the two slowly begin to neutralise each other out, so that within a day or two, the soap is safe to handle for cutting or removing from moulds. The soaps will continue to harden and neutralise, over a period of 3-6 weeks, at which time, most soaps are ready for use.
Castile soap is a soap historically made from 100% olive oil, to create a soap that is extremely gentle, moisturising and hypoallergenic, making it suitable for everyone in the household to use, including those with sensitive, dry or mature skin. Unlike other oils that are liquid at room temperature, olive oil hardens as it cures. This takes time, typically a year or more, to turn it from its liquid state into a super hard bar of soap.
The soap that we will be making is a twist on the classic, using 90% olive oil, with 10% Castor oil, for added foam, as soaps high in olive oil are known to leave a ‘slimy’ feeling on the skin (excess oil and glycerine which leave your skin feeling moisturised).
One further thing to note is that whenever you use someone else’s soap recipe, you should always run it through a soap calculator first – in case they made a mistake with their numbers. Input each oil by weight into the calculator (see table above taken from: https://www.thesage.com/calcs/LyeCalc.html), and it will calculate the amount of lye and liquid that you should use. (Note: all measurements in soap are by weight). This is also handy, if you’ve run short of an ounce of oil, or find that you’ve poured a little more into the pot than you’d intended to. Simply run the new numbers through the soap calculator, and adjust your liquid and lye to suit.
- Put your safety clothing on.
- Weigh out your water, and pour it into a tall sturdy plastic jug.
- Weigh your lye into a container.
- Whilst in a well ventilated location pour the lye into your water. Stir with a spatula or plastic chopstick until fully dissolved. Leave the lye to cool for approximately 1 hour, until it reaches 100° Fahrenheit or 38° Celsius (measure using jam thermometer).
- Weigh the oils and add them to your saucepan. Heat the oils until they reach 38°C, and then turn off the heat.
- When the lye and oils are approximately both at 38°C, slowly add the lye to the saucepan of oil. Intersperse manually stirring the stick blender, with turning the blender on for short 5 seconds bursts. Continue to do this, until the soap reaches light trace (estimate this taking 15 to 45 minutes). A ‘trace’ is when the stick blender leaves a mark on the surface of the soap, upon lifting/dragging it across the soap’s surface.
- Pour the soap into prepared (lined) box or silicone moulds. Cover the soaps with cling film, if required, before placing out of sight.
- Wait approximately 1 week before un-moulding and/or slicing your soaps.
- Place the soaps in a lined box, in a dry place, like a linen cupboard. Turn the soaps every so often, so that they dry evenly.
- Many soap makers leave containers used for making soap, until the next day to wash – as most of the lye will have been neutralised by this stage. Use good gloves and hot water.
Twelve months later and your first soaps will be ready to try. Use a soap dish to extend the life of your soap.
If you didn’t use cling film to cover your soaps, you will probably notice a white powdery substance on the tops of the soaps, where they were exposed to air – this is the result of ‘oxidation’ and is perfectly normal. This oxidation is called – soda ash.
Variations for this soap are endless, e.g. use a chilled nettle or clover tea, as your liquid, add 2 tablespoons of ground oats at trace, etc. Non-dairy milk and beer soaps involve additional steps, and will be covered in later tutorials.