Cold processed soaps need time to cure and age before they can be labeled and sold. The Hot Process method of making soap does make for a bar that can be sold right away however, their look and feel is not the same as cold process. Cold process soaps are usually smooth and hard bars of soap.
The explanation for why the bars need time to cure is easy to understand. We mentioned hot process above. This is when the soap maker continues to cook each batch of soap over a heat source, speeding up the process of the saponification process (the lye) and continues to evaporate the wax. With cold process soaps nature takes care of the curing process by allowing the soaps sit out in the open.
When the soap is made, the fatty ingredients (coconut, olive, shea, soybean) and blended with sodium hydroxide (lye) along with essential oils and color and spices or herbs. When the lye (diluted in water) mixes with the molecules of the fatty oils – what you end up with is soap. However, the soaping process, known as saponification, continues over the next couple of weeks. As the bars of soap are allowed to sit out in the air, the lye works its way out of the batch and the water continues to evaporate.
A bar of soap CAN be used after only two weeks of curing. It won’t harm you. But, softer soaps melt away faster in the shower or tub. When your bars of soap are allowed to cure a full four to six weeks, the end result is a very hard bar of soap. The basic rule is – the longer it sits, the harder it gets and the longer it lasts.
When you cut your soaps into bars, spread the bars out a bit. A slight space between each one is enough to allow air to reach all sides of the bar. But when the bars are crammed against each other it makes it harder for the water in the bars of soap to evaporate. Room temperature is best. Some customers with little space have even told me that they place the bars on trays and slide the trays under the bed with a small fan running in the room when they are at home. Shelves in the laundry room work well as a curing space for you soaps too. No other options? Clean off a shelf in your closet. True, there won’t be as much air circulating in there but the soaps will still cure and your clothes will smell amazing.
Another reason why some soaps need a longer cure time has to do with their ingredients. Soaps that contain honey usually feel more ‘oily’ in the beginning. If you label your honey soaps too soon it will leave an oily stain on the label.
If you follow the simple rules of how to cure your soap, it will make all the difference in the feedback you receive from customers. Their bars will last longer and they will come back for more. After all, you wouldn’t want to buy cheese that hadn’t been aged properly. Curing soap is similar.
For even more information on making & curing soap, check out Making Soap from Scratch: How to Make Handmade Soap – A Beginners Guide and Beyond by Gregory Lee White on our site here or on Amazon.com.