How to make cold process soap

26 July 2007

I'm sure many of you are wondering: "Why make soap when I can buy it cheaply at the supermarket?" My cold process soap is made with vegetable oils and when it is made and cured, it contains no harsh chemicals or dyes. Often commercial soap is made with tallow (animal fat) and contains synthetic fragrance and dye and retains almost no glycerin. Glycerin is a natural emollient that helps with the lather and moisturises the skin. The makers of commercial soaps extract the glycerin and sell it as a separate product as it's more valuable than the soap. Then they add chemicals to make the soap lather. Crazy.

Making your own soap allows you to add whatever you want to add. If you want a plain and pure soap, as I do, you can have that, or you can start with the plain soap and add colour, herbs and fragrance. The choice is yours.

I want to add a little about animal and bird fat. I know Kirsty makes her soap with duck fat and I think that's great. I think that if you're living true to your simple living values, and you're a meat eater, then you should be using every part of that animal or bird. Soap making helps you to do that. So if you raise beef, pigs or ducks, I'm pretty sure there are a lot of good soap recipes for you to use your animal fats. I will, however, be concentrating my post on what I make - vegetable-based soap.

EQUIPMENT
  • Stainless steel saucepan 
  • Wooden or plastic spoon 
  • Scales - most soap ingredients 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) 
  • Newspaper to cover your work area 

DON'T use any aluminium pots or spoons. You may use stainless steel or cast iron and your spoon may be of steel, wood or plastic.


RECIPE The recipe may change every time you make soap but the method of making it remains the same. This is the recipe I use now:
  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



Temperature conversion calculator http://www.onlineconversion.com/temperature.htm

WARNING
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.

Many soap makers wear latex gloves, goggles and a mask. I don't as I know what I'm doing and I'm very careful. 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 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. 

METHOD
Lay out the newspaper over your work area.


Grease your moulds.


Put on your safety gear.

Measure and weigh all your ingredients.

Weigh all your oils and place them in a saucepan.

Measure out the water and leave it in your measuring jug.

Measure out the lye into a small bowl.




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).




With the water already in the jug, carefully pour in the lye and stir gently until fully dissolved. Stand back a bit as there will be fumes coming up from this mix and it will heat up.




Now you need to have the oil at 50C and the lye at 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 - 10 minutes, making sure your blender doesn't overheat. I use an old Mixmaster (KitchenAid) as it has a very low setting that doesn't splatter. It gently stirs and reaches trace within 5 or 6 minutes. Don't use a hand beater and it splashes too much and the soap is still caustic at this stage.




TRACE
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. When you reach trace, slight ripples will form on the surface and remain there. 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.
If you're going to add fragrance, add it when you reach trace and give it a good mix. Then pour the mixture into the greased mould. I use a resin cake form that I bought for $2 at the dollar shop. You can also use plastic ice block trays, milk cartons or any plastic shape. Make sure you grease it - I use cooking spray, and if you're using a milk carton, make sure it's absolutely clean.



If you want to colour your soap you should research this yourself as I've never coloured my soap. Food colouring is unstable and not considered suitable, you'll need to buy soap dye or use natural powders like turmeric, cinnamon or cocoa.

Once the soap is in the mould, cover it with a towel so it cools down slowly.




The next morning, or about 15 hours later, release the soap from the mould and cut it into whatever shape you desire.


I add nothing to my soaps, but I do stamp them with a plain old rubber stamp. And I don't fiddle with the shape, I just cut them into blocks with a sharp knife. I like my soap to look handmade, but many soap makers fashion their soaps to look very professional and store bought. You do what you want to do.

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 can also use your soap to pour into loofahs that have been cut into disks. Just wrap the bottom of the loofah in a small piece of plastic wrap so the hot soap doesn't run through.
The next morning, or when it's set, just tidy up the top with a sharp knife and allow the loofah soaps to cure for a few weeks.


ADDITION: I forgot to add something about soap calculators. When you want to try a new recipe with different oils, you'll need to run the recipe through a soap calculator to give you the correct ratios of oils, water and lye. This is the one I use: http://www.snowdriftfarm.com/soapcalculator.htm Just fill in the weight of the oil you'll use and it will calculate your lye and water for you (for the recipe above we used 1.5 litres). This will give you the exact amount of lye and water you need to add. Then make the soap as above.