If you are comfortable with the basics of cold process soap making and looking for a new challenge, try making liquid soap. It is more complicated and takes a lot of patience. You'll likely notice a few changes in your soap making process, but if you follow the steps carefully, it is not too difficult.
The major difference between bar soaps and liquid soaps is the alkali used to saponify the oils. All soap, whether hard or liquid, starts with a simple chemical reaction between oils and an alkali. With bar soaps, it's sodium hydroxide. With liquid soaps, it's potassium hydroxide.
Liquid soap is a bit more complicated to make at home. For beginners, it's best to use a tried and true recipe that results in a good balance of lather and moisturizing.
For this recipe you'll need:
16.5 oz. sunflower oil
7 oz. coconut oil
5.5 oz. potassium hydroxide KOH
16.5 oz. distilled water for the lye mixture
40 oz. distilled water to dilute the soap paste
Either 2 oz. of boric acid or 3 oz. of borax mixed into 10 or 6 oz. of water
Approx. 3 oz. fragrance or essential oil, as desired
Soap dye or colorant, if desired
You'll also need:
Basic tools for mixing the lye
Large crock pot
Thermometer, scale, measuring cups
Stick blender
Potato masher and/or flat whisk