Storing Cold-Process Soaps
After the soap is fully cured, you have a number of storage options. Soap continues to lose water, which will make it harder and longer lasting. It is important to keep the cured soap where air will circulate around it. Try an open cardboard box with a piece of netting over the top to keep the dust out. Be sure the soaps are not crowded too closely.
Close crowding can cause pockets of moisture or oil to build up, which will contribute to spoilage. Additionally, crowding will facilitate scent transfer. For example, if you store differently scented bars together, they will take on each other's smell.
Eventually, most soap will spoil. The higher the percentage of extra oil in the recipe, the sooner this will happen. There are some preservatives you can use, including grapefruit seed extract, that are thought to retard spoilage. Your best insurance against spoilage is a correctly formulated recipe that doesn't have a large percentage of excess oil. This, paired with proper curing and storage, will make the soap stay fresh longer. If you plan to sell your soap, it is a good idea to know how long a bar from each recipe will maintain freshness. You can learn this by saving a new batch for at least six months. Keep records of how it ages.
You can make cold-process soap from a large variety of oils — from a single-oil soap such as 100-percent olive oil, to a complicated blend of exotic oils. With a little research you can get exactly the texture, hardness, lather quality, cleansing, and moisture benefit you want. You can leave the base recipe plain, or you can enrich it with color, scent, texture, and extra oils for moisturizing.