Cold Process Soap,  Soap

Introduction to Soap Making- Part 1: Cold Process

For Christmas, I got my niece a soap making kit from Joann’s or Amazon or somewhere like that. And I was reading the back and it looked like it was a lot of fun. So I read the ingredients, bought them all, and made my first batch of melt and pour soap. A smart person would have just ordered a kit. This lead me down a rabbit hole where I discovered there were 3 types of soap making. Melt and Pour, Cold Process, Hot Process, and liquid soap. Cold and Hot Process both use Lye to change fats and oils into soap, whereas Melt and Pour does that process before you buy the soap base and you just have to melt, customize and pour it into the mold. And making liquid soap is part 2 of the Hot Process. This Introduction to Cold Process Soap will focus on Cold Process. But I will cover the other three kids of soap making will be broken up into multiple parts: Cold Process, Hot Process, Liquid Soap, and Melt and pour.

This post is going to be a little different than other posts I’ve done. I’m going to give you an overview of each type of soap, tools you need, general safety tips, and some other great links. When I post recipes for soaps, I will link them to this page, as well as this page to those recipes.

Introduction to Soap Making- Cold Process

Cold Process (CP) Soap is more involved than making Melt and Pour Soap. It is using lye water to create a chemical reaction turning fat/oils through a process called Saponification. Many artisan use mica and natural colors to create designs. They will also use a combination of essential oils and fragrance oils to add scent to their bars.

Here is a high level over view of making soap.

Step 1: Set up your space

When making CP, it is important to clean your work area thoroughly and turn on any vents or fans and open the windows because you’re working with lye.

Gather together supplies so everything is near by. If you are using fragrance oils or types of color, read the directions on how they should be added to the soap base. Some color powders need to be mix with Water, Rubbing Alcohol or base oils. Some times fragrance oils can be used in this step. Prepare to colors when you gather your supplies.

Lye is a chemical that can burn your skin if it comes in contact with it. For this reason, I suggest long sleeves, pants, rubber gloves (or disposable gloves), and Safety Goggles. Some people suggest wearing a mask to protect from the lye fumes but I haven’t done this. There are some other add-ins that suggest wearing masks to protect your lungs. I also wear a denim apron.

Step 2: Measuring

After cleaning your workspace, measure out the water you need for your recipe and measure out your lye separately. Mix the lye into the water. NEVER mix water into lye, this can cause the lye to foam up and expand out of the container. In the soap world, this is called Volcano. So ALWAYS add lye to water. Set this aside by your vent or open window. Because of the heat reaction, I suggest using glass for this so you don’t melt any plastic containers.

Measuring out the Oils and Butters into a pot and turn it on to melt the oils. Do not add your fragrance oils or color at this point. I like to melt my hard oils first and then pour in my liquid oils. Hard oils are ones such as: Shea Butter, Coconut Butter, Palm oil, and Cocoa Butter among others.

While the oil is melting, prepare your molds. If you are using a wooden mold, line it with freezer paper, or parchment paper so the soap does not bond to the wood. Additionally, there are silicone liners available for loaf molds but if you’re just starting you can buy a set that includes Loaf Mold and liner.

Step 3: Blend.

Once oil melted and the lye solution has cooled down, then you can move on to combining them together. I aim for the temperature to be around 100 degrees F before I mix them together. Pour the Lye into the oils and use your stick blender to bring the mixture to an emulation.

You’re looking for the Soap to leave a light to medium trail when you stop and move around your stick blender.

Step 4: Colors and fragrances

Adding color requires some prep before you start your soap. Pay attention to manufacturer instructions. Micas need to be mixed with a light oil before being added to the soap base. I use the stick blender here to really disperse the color through the base.

Adding fragrance helps thicken the soap up. QUICK. So don’t be afraid to add fragrance oil and use a whisk to mix it completely into the mixture.

(Sorry my photo for this did not work out)

Step 5: Pouring and let it sit.

While it still looks like a thick-ish cake batter, pour it in to your molds. You can design your pour batter with a figure 8 set or

Helpful and Suggested tools Tools

  • Stainless Steel Pot– To heat your oils you want to use a stainless steel pot or microwave-safe bowl. All oils and butters should be liquid before adding the Lye Mixture
  • Glass Measuring Cups– I use these to measure out lye and liquid. The liquid goes in the largest cup and the lye goes into the smaller one.
  • Lightweight measuring bowls– You have to measure out everything. most lye and recipe calculators will list the recipe in grams or ounces. Lightweight bowls are easier on most kitchen scales than ceramic ones.
  • Kitchen Scale You have to measure it somehow.
  • Stick Blender– I don’t believe you can mix things by hand, you would need a lot of manpower to whisk this into an emulsion. Also, this adds very little air to your mixture.
  • Loaf Molds or Fancy MoldsYou have to put the soap in somewhere.
  • Rubber Spatchulas and a few whisks.
  • Rubber gloves (or disposable gloves), and Safety Goggles– Safety first.
  • Digital Thermometer– Colors and fragrances need to be in a certain temperature range to be added to the soap mixture.
  • 99% Rubbing Alcohol You need to sprits the top of your poured soap with this to prevent bubbles and potash.
  • Lye Calcuatlor– Because soap making requires science it is important to double check you recipe in a Lye Calculator. The two I like are’s Lye Calculator and The Soap Guild’s Lye Calculator.

General Thoughts and Notes of Cold Process Soap

I use silicone loaf molds for some of my soap making. These are the pretty things you can find for each season. Because I am using these for soap, this is all I’m using them for. I’m not sure how the lye in soap reacts to the silicone and it was suggested to me that these are no longer food safe after using it for soap making. I also use fun seasonal flower ones for

Buying Cosmetic Grade oils is cheaper then buying food grade.

There are two types of Lye. Potassium Hydroxide (KOH) is used to make liquid soaps while Sodium Hydroxide (NaOH) is used to make bar soap. The process of adding this to water is the same. Measure out water, measure out the lye, and then add the lye to the water and mix until fully incorporated. Be careful of the fumes and heat. Adding Lye to liquid creates a chemical reaction that causes heat. For this reason, it is suggested to freeze milks into ice cubes so that the heat does not scorch them.

Zap Test- When reading recipes and stories online about soap making, this a phrase you will run into. A Zap Test is when you place your tongue on a bar of soap, if you get zapped (like you would from licking both prongs of a 9-volt battery) then you have undissolved lye in your soap and it is not safe to use. You can also get PH Test Strips and test by foaming up the soap with water and placing the strip on the soap. The Strips should indicate between 9-10 because Cold process soap is naturally alkaline.

Don’t Forget

For more recipes, make sure to check out my recipe index. Cold Process Soap recipes are coming soon- Promise!

If you like the recipes that I’m making, please make sure to support Baking In Bucks on Patreon or buy me a coffee using Ko-fi.

This post contains affiliated links. In the event you buy the item linked, I will receive a small commission at no extra cost to you.


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