2 August 2011

How to make cold processed soap - V 2

I have tried to make this process and the explanation of it as simple as I can, but you must be aware that soap making is not cooking, it is chemistry. Rules apply and when they're not followed, that is when you have failures. I have never had a failed batch of soap and I'm sure that's because I researched, read AND UNDERSTOOD what I read and what I had to do. If you are going to make soap, research and read and make sure you understand what you're doing. Hopefully this post will help with that understanding.

There are two things I want to highlight:
  1. No matter what you read or what people tell you, there is no way to make soap without caustic soda/lye.
  2. You HAVE to weigh your oils - you will notice that the oil measurements are in grams and the water is in millilitres. This is because water has a specific gravity of 1 and therefore a weighed litre/quart of water will be the same as a measured litre/quart of water. Oil is not the same. Oil is lighter and therefore a measured litre/quart of oil is different to a weighed litre/quart of oil. If you don't understand that, maybe soap making is not for you.
Water and oil do not weight the same - oil is lighter, which is why oil floats on water. If you pour one litre of water into a jug and one litre of oil into a similar jug, the oil would weigh less than the water. Therefore if you pour one litre of oil into a one litre jug and think it's the same as 1000 grams, it's not. You must weigh your oil to get exactly the 1000 grams needed in this recipe.

I use silicon moulds that were probably made for small cakes. I can't tell you what moulds to use because I have only used these and you probably wouldn't be able to buy them where you are. Suffice to say you'll need either a large mould - and cut the soap when it's set, or you can use smaller shapes similar to mine. The pink ones I use are from Kmart but I don't think they stock them anymore.

I have found that the silicon moulds don't need greasing. If you do need to grease your moulds, use a cooking oil spray.

Coconut oil is getting to be quite expensive and sometimes it's hard to find. If that is the case and you're in Australia, you can use copha, which is available at the supermarket in the butter section. Enough copha to make this soap recipe will currently cost you around $2.66. Coconut oil solidifies when the temperature is 24c/76F. It's fine to use it either way; if it has solidified, just melt it with the other oil.

Each oil used is soap is used for a certain quality it has. For instance, coconut oil help soap lather well; olive oil is a good oil to base the soap on as it will nourish the skin and make a beautiful mild soap.  Low grade olive oil is the best olive oil to use, not extra virgin. Take the time to learn a bit about the different qualities of soap oils here. Once you know what you want and the oils that will give it to you, find out what's available in your neighbourhood and go from there. When you decide on the oils you would like to use, and know they're available to you, go to this soap calculator, put in your oils and the calculator will tell you how much water and caustic soda/lye to use.

I never use these so I can't advise you about their use.

The recipe may change every time you make soap but the method of making it remains the same.

You can use your kitchen equipment for soap making. Make sure you clean it thoroughly when you finished.
  • Stainless steel saucepan
  • Spatula
  • Scales - oils and caustic soda/lye are measured by weight, not volume
  • Jug - for holding oils
  • Measuring jug - for measuring water. It's ok to measure the water by volume
  • Thermometer - you can use either a milk or candy thermometer
  • Stick blender, optional but it's the easiest way to stir
  • Newspaper to cover your work area
  • Moulds
DON'T use aluminium pots, bowls or spoons. 

My new recipe for a good cold pressed soap is:
  1. 450 mls * rain water, spring water or distilled water
  2. 172 grams caustic soda/lye 
  3. 1000 grams olive oil 
  4. 250 grams copha or coconut oil 
* If you don't have rain, spring or distilled water, collect enough tap water the day before you make the soap and leave it on the bench to sit. That will allow the chlorine in the water to evaporate off.

If you don't operate in mls and grams, there is an online conversion calculator for liquid here and for weight here.

If you are new to soap making, be warned, it should never be attempted when children or animals are around. The lye (caustic soda) you will use, burns, and if you spill it on skin you need to wash it off immediately under running water or vinegar. If you drop it on the floor or bench top, wipe it up straight away as it will burn a hole. When you mix the lye with water, even though it's not on the stove, it will heat up considerably and burn if you drop any on yourself or splash it in your eyes. There are also fumes. When you mix the lye with the water, fumes will come off it. Make sure you mix your lye in a well ventilated room. If you're asthmatic, be very careful.

Many soap makers wear latex gloves, goggles and a mask. Please use these safeguards while you're learning to make soap. When you're experienced, you might be able to dispense with them.

Are you still with me after that warning? Soap making is a simple process that is made difficult by using lye (caustic soda). There is absolutely NO WAY to make soap from scratch without using caustic soda/ lye. If you make sure you're alone when making soap, if you have all your ingredients measured out and have a clean and clear work area, you shouldn't have any problems. The entire process should take about 30 minutes. BTW, the process of soapmaking - saponification - neutralises the lye and by the time the soap is cured, no lye remains in the soap.

Basically when you make soap, you mix the water and caustic soda/lye together and they will heat up without you doing anything to them. That is the first chemical reaction.  Then you combine the oils and heat them on the stove. Now you wait till the lye and water solution cools to around 50c and the oils heat up to 50c. You need them to both be at the same temperature and when they are you mix them together and start stirring. When you reach "trace" and that is explained below, you pour the soap into moulds and wait for it to set.


  • Lay out the newspaper over your work area.
  • Grease your moulds.
  • Put on your safety gear.
  • Open the windows for good ventilation.
  • Measure out the water into your measuring jug.
  • Measure out the caustic soda/lye into a small bowl.
  • Carefully pour the caustic soda/lye into the measured water.
  • Stir the water with a spoon until the caustic soda/lye is completely dissolved - about one minute.
Caustic soda/lye and water - mixed together.
  • Weigh your oils and place them in a saucepan.
  • Clip the thermometer onto the side of the saucepan and place on low heat on the stove. Slowly heat the oils to 50 degrees Celsius (122 F).
Copha and oils heating up.
  • Wait until you have the oil heated to 50C and the caustic soda/lye cooled down to 50C (122F). When they're the same temperature, carefully pour the lye water into the oils and avoid splashing it.
  • Start mixing. You can either use a spoon and stir for about 20 minutes or use a stick blender and mix for about 5 minutes, making sure your blender doesn't overheat. Don't use a hand beater and it splashes too much and the soap is still caustic at this stage.
Trace is the sign you look for that the soap has become stable and is ready to be poured into a mould. Before you reach trace, the surface of the mixture will be smooth, like pouring cream. When you reach trace, slight ripples will form on the surface and remain there, like thick custard. The mix should be thick, but pourable.

This is what the mix looks like when you've reached trace. Notice how there are ripple staying on the surface.
  • Once the soap is in the moulds, lay a sheet of parchment or grease-proof paper over the top and cover with a two towels so it cools down slowly.
  • The next morning, or about 15 hours later, release the soap from the mould. If it's a large mould, cut it into whatever shape you desire.
  • Place the cakes of soap on a drying rack in an area they can stay in for a couple of weeks. Turn the soap over every day to allow it to dry out evenly. I cure my soaps for about six weeks before using them. The drier they are when you use them, the longer they last. You could use your soap after a week or so, but when it gets wet it will go soft and won't last long. It's better to cure them for a few weeks. This batch made 12 hefty blocks of soap.
You will have trouble with your soap: 
  • if you don't weigh your oils
  • if you don't measure your water
  • if you don't weigh your caustic soda/lye
  • if you don't have both mixtures at the same temperature
  • if you don't stir long enough
Remember, soap isn't just a solid bar. It must lather well, clean and nourish your skin. 

Phew! That is the last post about soap I'll do for a while. I do want you to make your own soap but if you're not prepared to read, understand and follow the process exactly, then maybe this simple living task is not for you. If you get past the first soap making session and it results in good soap, I'm sure you'll go on to make it many more times. This is good soap, it's worth a bit of time, planning and effort.  Good luck!

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