Making cold process soap is one of our favorite hobbies. On this tutorial we are going to explain cold process soap making procedure so that you can create amazing, handmade soaps right in your kitchen. Once you get familiar with it, you’ll never want to buy soap from a store again.
If you are one of those people who hesitate to make cold process soap because it involves handling lye, we know that feeling. Lye requires caution, handle it with rubber gloves, safety goggles and long sleeves t-shirt. If you are careful, you most likely won’t get any splashes. In time you’ll get comfortable with the idea.
Now, let’s get started! First gather the necessary tools, organize your workspace (make room and cover your bench with newspaper) and select a recipe.
Step 1: Weigh our ingredients
Our first job is to weigh our ingredients. We weigh all the ingredients in grams (weight) and not ml (volume). Accuracy is key to successful cold process soap making. Making soap is not like cooking, where you roughly measure your ingredients or you don’t even measure them! In soap making, a few grams more or less than what the recipe says could completely change the result. So be extra careful in this first step. Weigh the ingredients and put them aside for the next steps.
Step 2: Prepare the lye solution
Take a 2-3 litre heat-resistant plastic or glass jug and put inside the water. Always use distilled water, because tap water contains unwanted substances (chlorine, fluorine and other minerals) that will take part in the saponification process. Remember to always pour the lye into the water, not the water into the lye! The reaction of the caustic soda with the water will cause a great increase in temperature. The temperature of the lye solution can reach even 90°C, so use a heat-resistant jug or bowl. You can read more about the necessary tools for cold process soap making here. Mix the lye with the water continuously until all the lye is dissolved. Because the temperature of the lye solution rises too high, it’s better to prepare it first so there is time for it to drop.
How much water should I use?
Most cold process soap recipes will specify the amount of water needed, but as a general rule use a 1/3 lye to water ratio – 3 parts of water for 1 part of lye. The water molecules don’t actually take part in the saponification process, they serve only as a solvent. If we use only the dry lye (sodium hydroxide), then it won’t be able to interact with all the oils in the recipe. The addition of water makes sure that the lye is spread throughout all the ingredients. The amount of water doesn’t have to be exact, however keep in mind that too much water will result in a soft soap, while too little water will cause a caustic and dry soap.
After you are done with the mixing and all the lye has been dissolved put one of the two thermometers into the liquid and put it aside for later use. Be sure to keep it in a safe place, away from children.
Step 3: Prepare the oils
As mentioned before, accuracy is very important to cold process soap making. If we put more oils than the recipe says, then our soap is going to be very soft, as it will contain non saponified oils. On the other hand, if we put fewer oils than the recipe says, then our soap will contain more lye than needed and it will be caustic and dry.
Some soap makers add on purpose more oils than the recipe says, so that the soap has more cosmetic and moisturizing properties for consumers. The addition of extra oils or butters that remain non saponified within the finished soap is a technique called superfatting or lye discounting. However, it is recommended for beginners, like us, to follow the recipe exactly, as most recipes are already super-fatted so that there is no risk of extra lye in your soap.
We pour the liquid oils or fats into the “Soap Pot” (stainless steel 8-12 litre pot with lid). If the recipe includes solid oils or fats we first melt them in a small saucepan and then add them in the large pot with the liquid oils. If we want to, in this step we can add some natural preservative, such as vitamin E. We put inside the thermometer and we leave the pot on the side.
At this point, we have a bowl with the lye solution and a pot with the mixed oils inside.
Step 4: Mix together
In order to mix the lye with the oils, they must have the same temperature. Most recipes give a specific temperature for mixing the lye with the oils. However, if you mix at a greater temperature that doesn’t mean that the soap will be destroyed. The goal is that the temperature of the oils isn’t too high, because they may lose their valuable properties. Temperatures of 30°C -50°C is acceptable and safe.
Tip: Because more likely the two mixtures won’t reach the desired temperature at the same time, you will have to adjust their temperature. You can either warm them up by putting the container into hot water or cool them down by putting the container into cold water. A nice solution is to do this in your kitchen sink.
When the temperature of the lye solution and the oils are in the same range, we are then ready to mix them together. Slowly pour the lye solution in the oils. Never the other way around. This is the most important step in the cold process soap making procedure. Mixing them together takes time. You must stir the solution constantly and in a brisklymanner so that all ingredients mix well. You could do it manually with a spatula, but this way it will take about an hour. A good solution is to use a stick blender which will speed up the process. You can read more about the necessary tools to make soap here.
How do I know when is my soap ready?
There is an indication of when our soap is ready, it’s called trace. Drizzle some soap from your mixing spatula or stick blender on the surface of the liquid. If the soap stays on top of the solution for a brief period before sinking back into the rest of the solution, saponification has taken place, and the soap is ready. To better understand what I’m talking about see the pictures beside. So, keep mixing until you reach trace.
Step 5: Adding the rest of the ingredients
When we reach the trace we are ready to add the rest of the ingredients, such as essential oils, fragrances or whatever we’d like our soap to contain. We stir very well until all the ingredients are mixed together.
Step 6: Molding
Our soap is now ready to pour it into the mold. There is a great variety of molds to choose from. You can either use individual molds in different shapes or one mold, in which case you will cut the soap into bars after it hardens. In the market you will usually find plastic, silicone or wooden molds. If you use a wooden mold, remember to line it with some greaseproof paper.
Step 7: Cover
Once our soap is in the mold cover it with a piece of cardboard and then wrap it with towels or a blanket. That’s way we insulate it and make sure that the heat doesn’t escape. This is essential for the first curing process. We leave the soap to rest for 24-48 hours.
Step 8: Unmold
After the 24-48 hours we unmold the soap and we cut it to bars of whichever size we want. If we used individual molds, we remove the already formed soap bars. Put the soap on a rack so that air can circulate around it (don’t stick the bars together) and leave it to rest for 6-8 weeks depending on the recipe.
Tip: The older the soap, the better for your skin. You could even leave to rest for 6 months. 6-8 weeks is the least that it needs to rest and be suitable for use.
The soap’s ph will drop significantly during this time of rest. This is our goal, since the highest the ph of the soap is, the more caustic it is for our skin. Before you use your soap, scratch of the white powder that may have been formed on top of the soap bars. These are remains of the caustic soda and while this is a good sign of the saponification process, it will dry your skin.
Step 9: Cleaning
Remember that the tools that you use for soap making are exclusively for this purpose only. Don’t risk cooking again with them, no matter how clean they look and don’t put them in the dishwater. If possible, clean them outside, in your balcony or yard and always wear protective equipment. Don’t forget that the lye is caustic. Finally, make sure to store your soap making tools in a safe place away from children and pets and clearly labeled “for soap making use only”.
We hope that you will enjoy this crafting experience as much as we do. If you have any questions, don’t hesitate to contact us and we’ll be glad to help you.