Here’s how to make soap using the cold process method, it seems complicated at first, but it’s quite easy once you get started.
This is one of four different soap making methods I use here on SavvyHomemade. I’ve found them all to be extremely addictive, and it’s one of the most wonderfully rewarding hobbies.
Let’s begin with the basics.
Below you’ll find my cold process soap making video and all of the information you need to get started, along with the basic soap recipe that I’ve made dozens of times. This recipe is one of my favorites, it’s made with simple ingredients to make a great creamy natural soap bar, it holds a good hardness and lathers up very well.
After you’ve mastered the basic cold process soap technique, I recommend that you take it a step further by creating your own unique soap from scratch using my calculator and formulation guide.
You also have some other techniques for soap making, such or my recent liquid soap tutorial. Or there’s the hot process soap which is quicker than cold process and less volatile, but perhaps not as pretty. And finally, you have the simplest form of soapmaking known as the melt & pour process if you want to make soap without using lye.
Begin By Watching How To Make Soap
Cheaper Than Store-bought Soap
Long before I started making my own soap, I knew that the cold process method would be the most authentic and difficult to master. But once I got the hang of it I quickly realized the total cost to make several months worth of soap bars was far cheaper than buying the chemical cocktails from the store.
Basic Supplies & Equipment
Once I learned cold process I quickly realized that because you have total control over what goes into your soap recipes, you can avoid using any ingredients that do not suit your skin.
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!
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 simple list of what’s required.
|The ingredients specified below or another cold process recipe|
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
Large stainless steel pan
Large plastic /glass jug or plastic bucket.
An old towel
Safety Before You Begin With Cold Process
A lot of folks express concern around the cold process soap making procedure, 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 making soap. 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!
Important things to remember when working with Lye
- All of the recipes on Savvyhomemade allow 5% superfatting. This ensures correct saponification (the chemical 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 it using a ph strip to make sure it is somewhere between 7-10.
- Make sure you are making your soap in a well-ventilated area. Put on protective eyewear, mask, apron, and long rubber gloves to protect the eyes and skin. Should you get some on your skin rinse with vinegar before washing it off using water.
- Once you add the Lye to water it creates a small chemical reaction, some choking fumes will rise from your bowl. This is the area that concerns most people, but all you need to do is 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 it.
For more reading on this subject take a look at my in-depth guide on why we use Lye which is definitely worth a read.
Adjusting The Volume Of Your Scent
You can adjust the scent volume here up to 3% of all the oils and water added together. Anything over 3% would be very strong depending on the oils you are using, so I recommend starting at 2%.
The recipe below is a good old fashioned soap that makes a great base for any fragrance, colorants, and exfoliates that you may wish to add. If making your own recipe, remember to use the lye calculator and formulation guide to get the correct volumes.
Let’s move on and take a look at the basic soap recipe, ingredients and method.
How To Make Cold Process Soap
- Large plastic /glass jug or plastic bucket.
- An old towel
- Gather and measure the ingredients shown above or from one of my other cold process recipes. You will need to measure your 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 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 it's 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.
- Now its time to mix the lye with water, and as I already mentioned above, this is a chemical reaction so we need to take some precautions.Make sure you are making the soap in a well-ventilated area. Put on protective eyewear, mask, apron, and long rubber gloves. Pour the mineral water into a large glass/sturdy plastic jug or plastic bucket. Now, slowly, pour 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, it's much easier.When both mixtures reach an equal temperature begin to pour the mixture and 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.I recommend combining at a balanced temperature of between 120F and 140F (49C-60C).Caution: Be very careful handling and mixing the lye. It is extremely caustic and can burn if it gets and stays on the skin. If at any point you spill or splash lye or caustic batter onto your skin, wash it off with lots of water right away. You can also use some kind of vinegar or lemon juice to calm the burning and wash away the lye, then rinse thoroughly with water. Remember that lye is alkaline, not an acid, and so a gentle acid should help to neutralize the lye. If this doesn't help, seek advice from a medical professional as soon as possible.
- 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 batter 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 recipe. But check the individual recipe to be sure. There are so many things that you can add, check out some of these interesting soap making ingredients and textures.
- Pour your soap into the mold and smooth out using a spatula.
- Place a piece of cardboard over the top of it.
- 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 it 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 it 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 bars 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 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.
- 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 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!
- 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.
So there you have it, the complete guide on how to make soap using cold process. It’s one of four different soap making methods, I hope you enjoy this craft as much as I do!
If you decide to have a go at making soap, I would love to see some photos and hear how you got on. Others have sent photos, you can see them here, so feel free to post yours in the comments below or using the contact form. And ask any questions if you need some help.