The term “castile soap” refers to a soap that contains more than 50% olive oil. Olive oil is a unique oil in that it can be used to make the oil part of the soap completely by itself. However, it comes with a cost: it does not foam. That is why we use castor oil to create the bubbles that we all enjoy.
Olive oil 855 g / 30,16 oz
Castor oil 45 g / 1,58 oz
Lye (Sodium hydroxide) 115 g / 4,05 oz
Distilled water 207 g / 7,30 oz
Step 1. Weight the oils in the pot
Step 2. Weight the lye in a separate dish
Step 3. Weight the distilled water in the third dish
Step 4. Slowly pour the lye into the water. Not the other way around, as this can evoke a strong reaction! Make sure you are doing this step close to an open window and remove your head away from the pot. Stir a few times with a plastic or stainless-steel spoon so the lye can dissolve in the water.
Step 5. Let the lye solution cool down to between 30-50 C / 86-122 F
Step 6. Heat the oils up to the same degree as the lye solution. Deviation up to 8 degrees is fine.
Step 7. Pour the hot lye solution into the oils
Step 8. Mix without moving the blender, then stir manually when it’s turned off. Do this until you get the trace, around 5 minutes.
Step 9. Put the soap in silicone mold
First option; cover the soap with cardboard and a towel. Leave for at least 24 hours but better for 48 hours.
Second option; put the uncovered mold in the previously heated oven (now turned off) on 50 C / 122 F and leave for 24 hours.
Step 11. Remove the soap from silicone mold and cut with the knife to 2 cm / 1-inch-wide slices
Step 12. Let them dry on the rack, covered with cloth, in cold and dark place, for at least one month but for best results dry for three months