Cold-Processed Method (CP)
Cold-Processed Method is a traditional but also a best way to manufacture nature soaps, its product so called Cold-Processed Soap (CP Soap). The process is called as such since the whole production process takes place within 50⁰C. This ensures that the oils and ingredients are still retain all their natural goodness, and the soaps retain their natural glycerin. Cold Process soap making is the act of mixing oils (plant oils, eg. Olive Oil, Coconut Oil, Avocado Oil, etc) with Lye (also known as Sodium Hydroxide, Alkali, NaoH). The result is a chemical process called saponification, where the composition of the oils change with the help of the lye to create a bar of soap. The soaps are then left for curing for 30-45 days before packing and selling them in the market.
** What is Glycerin? The gooey transparent layer on the soap is actually the highly prized glycerin which is extremely moisturizing for skin. Glycerin is the by-product of the soap making process. It is a natural humectant which helps to moisturize skin as it draws moisture from the air. In commercial soaps, this glycerin maybe removed and added to other products like skin care unlike handmade soaps where this glycerin remains intact.
** What is Lye? Lye is the chemical sodium hydroxide (NaOH). It is highly corrosive and will burn skin on contact, thus, have to handle it carefully and safety. In the process of making soaps, the lye reacts with the fatty acids in the vegetable oils to form a soap molecule. At the end of the 30-45 days saponification process (curing period), the lye would have completely reacted, so do not worry that there will be such harmful chemicals in the soap.
** What is curing? The process of curing soap takes time, normally 30-45 days, it may depends on the soap ingredients or formulas. However, is good for the final result as this process allows the excess moisture in the soap bars to evaporate, leaving a harder and longer lasting bar. The earlier a bar is used, the softer and possibly slimier the bar will be in the shower, and the less it will last. Additionally, the longer time for soap curing helps to produce the more gentle and long lasting bar of soap possible.
Hot-Processed Method (HP)
Hot-Processed Method is the other common used method whereby the mixture of oils and lye are heated up to 100⁰C-170⁰C. Because of the saponification process is accelerated with high temperature, its outcome so called Hot-Processed Soap (HP Soap). The hot and cold methods of making soap are very similar, each may using the same base recipes and combining the ingredients in more or less the same way. However, Hot-Processed Method requires an external heat source to bring the soap to the gel phase before it is placed in a soap mould; this part is most different with the Cold-Processed Method, which it is use its own self generated heat to reach the gel phase after it has been placed into the soap mould.
Through the Hot Process with high temperature, the soap can be ready for use just in a short time. However, most of the original nutrients and natural glycerin from ingredients are outflowed at the end of the process when the final soap is obtained. These soaps are usually more drying as they lossed its natural humectant. Therefore, additional glycerin (plant glycerin or synthetic glycerin) from outsource will be added in to these soaps in order to replace the natural glycerin. If they are, they may contain many preservatives to lengthen the shelf life of the soaps. In commercial use, the glycerin that is drained off is often later processed and sold for use in the manufacture of pharmaceuticals, make up, skin care products and food processing. Hot-Processed Soap no requires for long curing period as Cold-Processed Soap, just allows the soap to be fully saponified and immediately ready for use within a few days. This express result extremely suit for commercial production, because they require speedy production to fulfill high volume orders.
Melt and Pour Method (MP)
In the manufacture of melt-and-pour soaps, there is no direct saponification process for such soaps. In the melt-and-pour process, ready-made soaps (a soap base, usually its own natural glycerin has been drained off) that are made using the hot-process method are simply further processed so that they can be melted down and poured into moulds of various designs, usually synthetic dyes are also added to create attractive pieces of soap. However they have lost most of the natural compounds during the hot process.