Here’s how to make soap at home using the cold process method. 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 creative hobby.
Long before I started my DIY crafts I knew that learning how to make your own soap using cold process would be the most authentic and difficult method, 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 your homemade soap recipes, you can avoid using any ingredients that do not suit your skin.
Supplies & 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 to start making soap at home will not break the bank!
To begin with, here’s a list of what’s required for making cold process soap.
- The ingredients specified below or in one of my other cold process soap recipes
- Soap making mold
- Soap cutter and box
- Hand whisk or basic stick blender
- 2 candy thermometers or a lazer temperature gun
- Digital kitchen scales (grams)
- Safety glasses and long rubber gloves
- PH strips for safely testing acidity, available cheaply at Amazon
- Large stainless steel pan
- Large plastic /glass jug or plastic bucket.
- Plastic spatula
- An old towel
How To Make Soap Using Cold Process
Safety Before You Begin Your Soapmaking
When learning how to make soap at home a lot of folks express concern around the cold process, in particular the dangers of working with Lye and yes you do want to take some precautions whenever you handle it. Lye is the most common alkali used for soap making. Its official name is sodium hydroxide (NaOH) and is also known widely as caustic soda.
Having said that, all that’s required is a bit of common-sense. Which you already have otherwise you would not be reading through this guide!
- All of the soap making recipes on Savvyhomemade allow 5% superfatting. This ensures correct saponification (the reaction that creates soap) making sure there is zero free caustic alkali remaining and a good ph balance is achieved. As long as you have measured your ingredients correctly you have nothing to worry about. To be sure always test soap using a ph strip to make sure it is somewhere between 7-10.
- When making your own soap at home 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 breathe 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.
- Never leave your soap mixture unattended, this is a big no no especially if you have children or pets in your home.
- When cleaning your soap 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.
- Don’t be tempted to use your soap until you are sure that it has cured, if in doubt test it with a ph strip to make sure it is somewhere between 7-10. If you made a mistake and after 4 weeks it measures above 10 don’t just throw it away as you can rebatch soap.
The Basic Soap Recipe
Below is the basic soapmaking recipe that I’ve made dozens of times. It’s one of my favorite soap recipes, it’s made with simple ingredients to make a great creamy natural soap. It holds a good hardness and lathers up very well.
It’s also a good old fashioned lye soap recipe that makes a great base for any fragrance, colorants and exfoliates that you may wish to add.
Ingredients For The basic Soap Recipe:
Makes about 12 standard or 10 chunky bars:
- 380g Shortening (vegetable fat)
- 330g Coconut Oil
- 300g Olive Oil
- 310g Mineral Water (distilled water)
- 145g Soapmaking Lye (caustic soda)
- 25 ml (6 tea spoons) Essential Oil or Fragrance oil
Note on adjusting the volume of your Essential oils or Fragrance oils:
You can adjust the scent volume here. Iv’e set it at 25ml which is 2% of all the oils and water added together. Depending on your preference you can increase it up to 5% which in this recipe would be 66ml Max. That however would be very strong depending on what oils you are choosing, so I recommend starting at 2%.
The Cold Process Method:
Gather and measure the ingredients shown above or from one of my other cold process soap recipes.
You will need to measure your soap making ingredients carefully, Do Not try to guess or use cup sizes as when you make soap it needs the correct mixture to complete the saponification process. Use either grams or ounces, do not mix the two.
I prefer grams as I find it much more accurate, if you need to convert ounces into grams for any reason simply multiply by 28.35. More information on measuring, easy conversion and other cosmetic tips can be found here.
Prepare 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. Recently I’ve been using silicon molds as its so much easier to remove the soap.
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.
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!
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 lye (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. Update; I now use an infrared thermometer gun I bought on Amazon, it’s much easier.
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 for several minutes, slowly at first without switching the blender on.
Reaching The ‘Trace’ Stage: 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. 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.
Or by hand which will take a little longer, maybe up to an hour but with consistent slow even stirring with a hand whisk you will eventually reach the trace stage.
And now is usually the time to add any extras like flowers, fragrance, essential oils, colors or textures into your soap recipe. But check the individual recipe to be sure.
There are so many things that you can add when you make your own soap, check out some of these interesting soap making ingredients and textures.
I’ve noticed that soap making recipes containing beeswax usually reach the trace stage after about 15 minutes, so they’re worth looking out for.
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 learning how to make your own soap for gifts, or just for personal use I am fairly confident once you start using your 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 my soapmaking journey I bought the cheapest stick blender I could find 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 soap has hardened (usually around 24 hrs), remove from the mold and allow it to air for a few hours.
As a general rule it should be about the consistency of hard cheese before you cut it. The soap will still be caustic at this point so I would recommend still handling it with gloves for the first 48 hours.
Cut your soap into blocks, for this you can simply cut by hand for a more rugged look or use your soap cutting box for something more symmetrical.
Next 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 ventilated place turning them each day in the first week and then every other day thereafter for 4 weeks.
This time continues the curing process ensuring that all of the lye has been neutralized and water evaporated. During this time you may find a fine dust on your soap, this is soda ash and can be scraped off before use.
All of the cold process soap recipes on Savvyhomemade allow 5% superfatting. This ensures correct saponification (the reaction that creates soap) making sure there is zero free caustic alkali remaining and a good ph balance is achieved.
As long as you have measured your ingredients correctly you have nothing to worry about. To be sure always test soap using a ph strip to make sure it is somewhere between 7-10.
Possible Problems With Cold Process Soap Making
- 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 too 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.
More Cold Process Soap Recipes
I hope you enjoyed learning how to make soap at home, please remember to come back and post your own recipes and photos, you can join the fun by posting them here!
Now, let’s take a detailed look at some of my favorite soap making recipes.
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