Here’s how to make homemade soap using Cold Process. It seems complicated at first, but it’s actually very easy and not much harder than baking a cake. In fact, I’ve found it to be extremely addictive, and a wonderfully rewarding hobby.
Long before I started my DIY crafts I knew that cold process was the most authentic and difficult method used to make homemade soap, but once I got the hang of it I quickly realized the total cost to make several months worth of bars was far cheaper than buying the chemical cocktails from the store.
I also realized that because you have total control over what goes into soap recipes, you can avoid using any ingredients that do not suit your skin. The live cultures and stimulating enzymes within cold process soap recipes make them unbeatable for bringing life and vitality to your skin, for a fraction of the cost!
Equipment Needed For Cold Process Soap Making
The full rundown of items that I recommend can be found at wholesale soap supplies and equipment. Some of them you will have already, some you can make and some you will need to purchase. These items are not very expensive, so your setup costs will not break the bank!
To begin with, here’s a quick list of what’s required to make homemade soap.
- Ingredients from one of my cold process soap recipes.
- Large stainless steel pan.
- Suitable mold, most of mine come from Amazon.
- Large plastic /glass jug or plastic bucket.
- Plastic spatula.
- 2 candy thermometers, again from Amazon.
- Digital Kitchen Scales For Soap Making, right now the Ozeri Pro is a good choice.
- Apron and long rubber gloves.
- Safety glasses, these are also available from Amazon.
- Hand whisk or stick blender, I use the Proctor Silex.
The only other thing I could recommend would be a good book on making soap, when I started I got a copy of The Soapmaker’s Companion, it’s a great book with all of the information you will ever need.
Safety Before You Begin
A lot of folks express concern around the dangers of working with Lye, and yes you do want to take some precautions whenever you handle it.
Having said that, all that is required is a bit of common-sense. Which you already have otherwise you would not be reading through these safety tips!
So, always protect the eyes and skin by putting on safety glasses and rubber gloves. Should you get some on your skin rinse with vinegar before washing it off using water.
Once you add the water to your Lye some choking fumes will rise from your bowl. Keep your face away from these fumes while you stir the mixture and try to not breath them in. You could use a mask here if you want. I wrap a scarf around my nose and mouth and that’s probably sufficient, as the fumes only last a few moments.
When cleaning your soap making pot, allow the mixture to solidify and scrape it into a bag to be sealed and disposed of. Keep your gloves on when cleaning and add some vinegar to your washing up water to help thoroughly clean your utensils.
Here is a basics tips video, I recommend that you watch it all the way through.
Preparing A Soap Mold
If you don’t have a specific soap mold, then any good size container will do. Sturdy plastic containers that still have enough give to ease the soap out make the best containers because you don’t have to line them.
A quick grease round with a little solid oil from the recipe, and they’re good to go. Glass, wood, ceramic or cardboard all lined with freezer/butcher paper will also make suitable molds. Avoid using any metal molds unless you can be sure they are stainless steel.
To get a good idea of the size of mold needed add together the oils and water in the recipe and then fill a mold with that amount of water.
The best way to line your mold when using the freezer/butcher paper is to cut two strips, one to go across the width of your box and the other going across the length. Leave enough on the paper to fold over the edges and secure with tape.
Cold Process Method
- Gather and measure the ingredients from one of our cold process soap recipes. You will need to measure your ingredients carefully, Do Not try to guess or use cup sizes as when you make homemade soap it needs the correct mixture to complete the saponification process.
- Put on protective eyewear, mask, apron and long rubber gloves. Pour the mineral water into a large glass/sturdy plastic jug or plastic bucket. Slowly, add the caustic soda, using a plastic spatula to stir until dissolved. The water will start to heat when it reacts with the lye, it will need to cool until it reaches the required temperature (see specific recipe).
- In a large stainless steel or enamel pan, gently melt any oils or waxes over a low heat. ( this does not include essential or fragrance oils).
- Use two candy thermometers, place one in the caustic soda mix and one in the oil mix. When both mixtures reach an equal temperature (see specific recipe) begin to stir the lye into the oil, do this SLOWLY, and remember that you should always add lye to other materials, not the other way around, pouring a liquid into lye crystals can cause it to splash and can burn your skin.
- Using a stick blender:
Begin carefully stirring your mixture with a stick blender for several minutes, slowly at first without switching the blender on. Then give your mixture a few short 3 second bursts, stirring between each burst until the mixture thickens slightly and looks a little like thick custard. This is called “trace” and it’s a sign that your soap is turning out well.
- Or Mixing by hand:
This will take a little longer, maybe up to an hour longer but with consistent slow even stirring with a hand whisk you will eventually reach the trace stage. I’ve also noticed that soap recipes containing beeswax usually reach the trace stage after about 15 minutes, so they’re worth looking out for. By dipping your spatula or spoon into the mixture and dribbling a small amount back into the mix. It should leave a light “trace” behind (like a small mound of soap that takes a few seconds to blend back within the mixture.) This is when you know you’ve reached the “trace” stage. And now is the time to add any extras like fragrance oils, colors or textures into your soap recipe.
Although a hand whisk can be used to reach the trace stage it can be quite time-consuming sometimes taking up to an hour to reach the trace stage. A stick blender can do the same task in just a few minutes.
Whether you are thinking of making soap for gifts, or just for personal use I am fairly confident once you start using your homemade soap, the store bought stuff will be a thing of the past so a cheap stick blender will be well worth the investment.
When I started I bought the cheapest one I could find, and at the time that was the Proctor Silex hand blender and it works great!
- Pour your soap into the mold and smooth out using a spatula, place a piece of cardboard over the top of it, and wrap an old towel around the whole thing to keep the heat in. Allow your soap to set for 24 hours in a warm place until the soap has hardened. Don’t be too alarmed if you take a quick peek at your soap and it looks translucent, this is called the gel stage and is perfectly natural.
- When the homemade soap has hardened, remove from the mold and allow the soap block to air for 1 or 2 days depending on the softness of the soap before cutting it into blocks. The soap will still be caustic at this point so I would recommend still handling it with gloves for the first 48 hours.
- Cover/line a cooling rack, tray or box with a cloth and stand the soap blocks upright without touching each other so the air can circulate. Store them in a dry place turning them each day in the first week and then every other day thereafter for 3 to 4 weeks before using. And always test your soap on your hands before using on your face.
I make a lot of soap and I found a great little tip that helped out. This was to buy a simple, cheap plastic cutlery bin from Amazon.
As you can see in the photo to your right it’s a great half moon shape and was perfect for the goats milk soap.
It also has a little give in it to help ease the soap out. It makes around 10 large bars per compartment… Perfect for making multiple batches of soap!
Possible Problems When You Make Homemade Soap
If your soap does not harden or just hasn’t turned out quite as well as you expected it to, or maybe you forgot to add something. Then you may be able to rebatch it by melting it down and adding any missing, or miss calculated ingredients.
If your batch is to lye heavy, making it very brittle and crumbly or if your lye and oils have separated (you will notice a layer of liquid on the top or underneath the soap) I would encourage you to discard it.