I am getting ready to make soap all weekend and thought I would share the different ways you can make soap. Each option has it’s own unique benefits. The four types of natural soap include: cold process, hot process, rebatching, and melt and pour.
Cold Process Soap Making
In this method, oils are melted and combined with a lye and liquid (water, milk, etc) mixture. Mixing these ingredients creates a chemical reaction called saponification. The mixture is then stirred either by hand with a spoon, or by using a stick blender until the soap mixture has thickened (called ‘trace’). There is no cooking (using heat to speed up the saponification process) with cold process soap. The mixture is poured into a mold, covered and left to cool for 24 hours. At that point the soap can be removed from the mold and cut into bars. The bars are then left alone to cure for 4-6 weeks. This ensures a harder and milder bar of soap. I love cold process soap making and use many different types of liquid. One of my favorite is pulverizing avocado and adding the fresh avocado to the lye.
Hot Process Soap Making
In this method, melted oils are combined with a lye/liquid mixture and are ‘cooked’ by using heat. Many modern soapers make hot process soap in a slow cooker/crock pot. The mixture is brought to trace and then cooked. The cooking time varies depending upon the ingredients used, the size of the batch and the heat setting on the slow cooker. The end result is a thickened, gel-like looking soap mixture that must be spooned into the soap mold. It is covered and left to cool for 24 hours, at which time it is removed from the mold and cut into individual bars of soap.
This method is often used to reduce the 4-6 week cure time required by cold process soap making. By the time the soap cools and is removed from the mold (usually within 24 hours), the soap is safe for use. Leaving it to sit for a couple of weeks may allow additional water to evaporate and become harder, but it is not necessary. Hot processed soap may have a more rustic, handmade appearance to it, compared to the smooth texture of cold process soap.
This method involves using pre-made soap (cold or hot processed). The biggest draw for soap makers to use this method is that they can buy pre-made soap for rebatching and do not have to come into contact with lye if that’s a concern for them. The lye has already been chemically transformed during saponification. It also means they can add additional ingredients such as essential oils or herbs and not have to worry about them reacting with lye.
To rebatch soap, the pre-made soap is grated like cheese and to this a small amount of liquid is added. The mixture is gently heated until melted and then pressed into molds. It must then cool and harden before it is suitable for use.
Melt and Pour Soap Making
This process involves purchasing a premade glycerin soap base (or making a glycerin soap base on your own, which is much less common, but possible), and melting it down, often in a microwave or on a stovetop. At that point, colorants, fragrance and possibly some additional oils (no water or milk can be added) are added to the melted soap base. The mixture is then poured into molds and left to harden – usually just a few hours. At that point, the hardened soaps can be removed from the mold and are ready for immediate use.
Some soap makers prefer using this method because the chemical process has already been done, so they don’t have to worry about using lye. Melt and pour soaps are also fluid enough to be poured into a variety of molds which results in more intricate designs and shapes compared to the other types of soap making.
All of these methods produce great soap with wonderful properties. Off I go to start my soap making weekend. Wish me luck!
To saponification success!