How to Make Liquid Castile Soap

Castile soap, also known as vegetable soap, is soap that contains no animal fats. It is made primarily with olive oil but it can also contain other plant oils. Making liquid castile soap at home can save you money and give you the peace of mind of knowing that no harmful ingredients have gone into your soap.


  1. Image titled Prepare ingredients Step 01
    Place 14.1 oz. (417 ml) coconut oil, 14.1 oz. (417 ml) liquid soybean oil and 18.8 oz. (555 ml) olive oil into a crockpot.
  2. Image titled Set your crock pot on high heat Step 02
    Set your crock pot on high heat. If your crockpot has a setting for hours, set it to 4 hours.
  3. Image titled Protect yourself Step 03
    Put on safety glasses, gloves and a long sleeve shirt or coveralls.
  4. Image titled Pour water into container Step 04
    Pour 32.9 oz. (973 ml) of distilled water into a large heat-proof container.
  5. Image titled Add lye to water Step 05
    Add 9.39 oz. (277 ml) of lye slowly to the distilled water.
  6. Image titled Stir lye and water mix Step 06
    Stir with a heat-proof spoon until the lye is dissolved.
  7. Image titled Pour the lye water mixture into crockpot Step 07
    Pour the lye/water mixture into the crockpot slowly, stirring it into the oils constantly
  8. Image titled Blend with a stick blender Step 08
    Blend with a stick blender for 15 minutes.
    • The mixture might try to separate, but just keep mixing.
  9. Image titled Stir with a spoon Step 09
    Stir with a spoon when the mixture becomes too thick for the stick blender.
    • Continue stirring until the mixture becomes too thick and you can no longer keep it moving.
  10. Image titled Place the lid onto the crockpot Step 10
    Place the lid onto the crockpot and set the heat to medium. If your crock pot has an hours setting, set it to 6 hours.
  11. Image titled Stir every 20 to 30 minutes Step 11
    Stir every 20 to 30 minutes.
  12. Image titled Turn off the heat Step 12
    Turn off the heat when the mixture becomes clear and has the consistency of thick honey.
  13. Image titled Transfer the mixture into stainless steel pot Step 13
    Transfer the mixture into a large stainless steel pot.
  14. Image titled Pour water Step 14
    Pour 80 oz. (2365 ml) of distilled water onto the mixture.
  15. Image titled Allow it to sit overnight Step 15
    Allow it to sit overnight or until the thick mixture is dissolved.
  16. Image titled Pour liquid soap into containers Step 16
    Pour your homemade liquid castile soap into storage containers, such as the empty distilled water jugs.
  17. Image titled Let it age for 4 weeks Step 17
    Let it age for 4 weeks.
  18. Image titled Add fragrance oil Step 18
    Add fragrance oil to each container as you use it.


  • An alternative liquid castile soap recipe can be made faster by grating a couple 4 oz. (118 ml) bars of castile soap and mixing it in a large pot with 4 cups of water. Stir until the soap pieces dissolve then add 2 tbsp. (30 ml) of vegetable glycerine. Continue stirring until the glycerine has dissolved. Transfer the soap to a jar and cover. You can use this soap right away.


  • Do not use the crockpot for food after making soap. It might be a good idea to get a used or inexpensive crockpot for soap making and keep it separate from your kitchen ware.
  • Castile soap may damage the finish on some sinks and drain or stopper fixtures.

Things You'll Need

  • 14.1 oz. (417 ml) coconut oil
  • 14.1 oz. (417 ml) liquid soybean oil
  • 18.8 oz. (555 ml) olive oil
  • Crock pot
  • Safety glasses
  • Gloves
  • Long sleeve shirt or coveralls
  • 32.9 oz. (973 ml) distilled water
  • Large heat-proof container
  • 9.39 oz. (277 ml) lye
  • Heat proof spoon
  • Stick blender
  • Large stainless steel pot
  • 80 oz. (2365 ml) distilled water
  • Storage containers
  • Fragrance oils (5 to 10 drops per container)

Article Info

Categories: Soap Making