Cold process soap making is the original, traditional method of making soap by combining fat or oil (animal or plant based) with sodium hydroxide lye then blending in addition of essential oils and colorants as required. This treatment causes a chemical reaction called saponification which takes up to 48 hours. Then after an additional slow curing process of about 4-6 weeks, leaves us with the product that we recognise as soap.
Cold process soap making is time consuming and involves the handling of a fairly toxic ingredient (lye) but this slow and traditional method is really very satisfying and does produce a superior project in the end. The lack of heat will ensure that essential oils are not ruined but instead remain intact and release their therapeutic properties through the lovely lathery soap that you make.
Cold Process Soap Making vs Melt & Pour Method
- The cold process method of soap-making is the traditional method of soap-making using the raw ingredients from scratch.
- The main difference in techniques is that cold process soap-making uses Lye, which is pretty nasty until it is disarmed through the saponification process. So you need protective clothing, gloves, a mask, eyewear and a very well ventilated space.
- Melt & pour is an easy way to make customized soap at home without handling some of the more caustic chemicals (like lye) or purchasing safety gear. As such, this method is more appropriate for children. However, there is heat involved as the name suggests so care is still needed.
- The melt-and-pour method of soap making is taking pre-made soap that has already been through the saponification process which you melt down. Then you can add in scent and colorants, and pour into a mold to harden. You are essentially just ‘finishing’ the soap making process.
- Time is a major difference too. With cold process soap-making, once poured into the mold, it takes anywhere from 24-48 hours for that saponification process to occur so it needs to be handled very carefully or left alone during this time. Then you need to sit on your hands for a further 6-8 weeks while your handiwork fully cures. Melt & pour soap is ready to use within a few hours.
- The main disadvantage of melt & pour soap is that you cannot create quite such beautiful designs in your soap. The batter is quite thick and will harden quickly so patterns and swirls are hard to achieve and additives (such as flowers) tend to sink to the bottom.
- The cold method batter is quite thin and therefore easy to manage when trying to create patterns or adding nice things, which is why cold process soap-making is favoured by artisan makers and crafts people.
- Cold process soap heats from the inside out, while hot process soap heats from the outside in.
- Cold process soap bars tend to last longer than a heat & pour made bar.
Steps to Cold Process Soap Making
Warning! This process involves handling lye which is a very toxic and dangerous substance. It can burn skin, damage eyes and release fumes that when mixed with water can burn and seriously damage your lungs and throat. We highly recommend that the first time you do this process, you do it in a supervised setting, such as our Cold Process Soap Making workshop.
1. Mix the lye, leave to cool down
2. Melt the solid oils/butter
3. Add liquid oils to melted oils
4. When temperature of lye and oils is around 40°C, pour the lye into the oils and stir with your spatula
5. Once the liquid thickens, add botanicals and essential oils
6. Pour the soap mixture into mould
7. Insulate with towel/blanket
8. Leave it for 2 days
9. Demould and cut
10. Leave to cure for 4 weeks
11. Check the pH with pH strips – the pH should be between 7 and 10
12. Use your soap
It is important that the soap cools down very slowly, to ensure that there is an even cure all through.
This is the reason this method can’t be used to pour into small individual molds as they cool too quickly.
Cold Process Soap Making Supplies
https://www.thesoapkitchen.co.uk/ for everything you need
https://www.mysticmomentsuk.com for clays, essential oils…
http://www.themouldsshop.co.uk/ for moulds
Soap-Making FAQs
Is cold process soap better?
Soap makers tend to prefer one method over another. The cold process can be individualised to refine every amount of each ingredient , add fresh fruits and milk and many people consider it a more creative method as the thicker consistency allows for a great number of heavier ingredients to be incorporated.
Can you use plastic molds for cold process soap?
When making cold pressed soap, the curing process requires a warm environment and a very slow cooling process. It is possible to use a large plastic mold- preferably with a wood case to hold the shape and slow the cooling process.
When can I unmold cold process soap?
Leave to cure for 4 weeks and then unwrap your lovely soap, breathe in that heavenly perfume and use- or give away.
The History of Cold Process Soap Making
People have been finding ingenious ways for getting things clean for about 5000 years and an early version of soap has been found in Mesopotamia predominantly used for cleaning cooking utensils, textiles or for medicinal purposes.
Throughout history, the basic soap ingredients of fats, oils and alkaline salts have been refined and adapted most likely based on what resources were readily available. For example the Phoenicians and the Celts used animal tallow (fat) and plant ashes, whereas early Romans found urine to be their star ingredient. It was however, these forward thinking Romans who first introduced soap as a means of personal hygiene. Progress indeed.
For most of history, the use of soap was reserved for the wealthy because it was incredibly expensive and the preserve of a small number of skilled soap makers, in much the same way as you would have blacksmiths, bakers and carpenters.
By the 13th Century in the Middle East, soap-making had become more industrialized and new vegetable-oil soaps were popular amongst the upper classes due to their mildness and infused aromatic fragrance. It was the Christian crusaders and traders that brought them back from places like Syria to Europe to spread their soapy goodness. Following this France, Italy, Spain and even England began to develop geographical soap making bubbles (get it) of their own.
Soap Making was still all fairly small-scale production until the chemistry was more widely understood and there were two major discoveries of how to make the common ingredients less expensively between 1780 – 1790.
The Industrial Revolution of the 19th Century allowed soap-making to become more mainstream and thus a separate commodity from laundry soap. These mild little bars were packaged and sold for personal use, much as we still see today.
Learn more about the origins of cold press soap making from our blog post here >>>
Here’s a fun fact – The Latin for soap is ‘ Sapo’, which is where we get the English word for soap.
Our Resident Soap Maker – Alex Dudal
Alex Dudal grew up in France and learnt to make soap from the soap maker at Trill Farm in Devon. She then took over that position and produced their classic Lavender and Pine round bars. In line with their ‘pure ingredient’ philosophy, the soaps use herbal extracts made at Trill. Alex now produces soap for Neal’s Yard remedies. Their soap is palm oil free and guaranteed organic.
