Rosemary and Peppermint Liquid Soap

Here goes my second batch of liquid soap! I am basically following the same recipe as the last time, but I left the crock pot on the high setting for the whole time. I think the reason why the soap took so long last time was because I kept (neurotically) checking the temperature and switching between the low and high settings. Honestly, the precise temperature does not matter – “hot” is enough.

The one different thing – I remembered to weigh my crock pot empty this time so diluting the soap paste with water was easier. The empty crock pot weighed 90.65 oz.

This recipe is for about 3 quarts of liquid soap.


*All measurements are weight measurements, not liquid measurements.

  • 7 oz Coconut Oil
  • 16.5 oz Sunflower Oil
  • 16.5 oz water for the lye
  • 5.5 oz lye (Potassium Hydroxide)
  • ~90 oz water for the soap paste
  • 3 oz borax (I used 20 Mule Team) in 6 oz of water
  • 1 oz rosemary EO
  • 1 oz peppermint EO

Base Oil Composition:

  • 30% Coconut Oil
  • 70% Sunflower Oil


  • stick blender
  • heat safe containers
  • crock pot
  • thermometer
  • scale
  • potato masher


Make sure you follow all the general safety precautions for making soap before you start.

  1. Pour the oils in the crock pot and start to heat them to 160F. The oils should be at about this temperature for the entire process (give or take 20 degrees).
  2. Pour the lye into a heat safe container with the water. Make sure you’re in a well ventilated area, and mix well. KOH makes a funny groaning noise as it’s dissolving (normal).
  3. Combine the lye water and oils in the crock pot as soon as the lye is completely mixed (clear solution). No need to wait for lye to cool or oils to reach the target temperature! Stir gently.
  4. Pulse with the stick blender until you reach trace. Sunflower oil is really slow to get to trace, so you might be blending for about 15-20 minutes.
  5. Put the lid on the pot and let the mixture rest for 20 min. If there is any separation, stir for a bit, and replace the lid.
  6. Check on the soap once an hour for the next 5-6 hours, stirring it when you check on it.
  7. The soap will go through lots of stages: “thick applesauce”, “custard”, “mashed potatoes”, “taffy”, “chunky vaseline”, and “translucent vaseline”. The worst ones are the “mashed potatoes” and “solid taffy” stage. Even with the potato masher, it is tough to move it around.
  8. Once the soap has softened and turned translucent (vaseline stages), check if it has cooked long enough. Combine 2 oz boiling water and 1 oz soap paste. Mix it really good. Then let it cool down. If the cool mixture is clear or lightly cloudy, you are on track. Otherwise, if it is milky, cook for longer or perhaps there was a mis-measurement.
  9. I read you should dilute the paste such that the final solution is 30% soap paste. For me, since my soap paste weighed 2 lb, this means that I needed to add 56 oz of boiling water. For whatever reason, this was not enough, and I added about 90 oz of water to the soap paste (in total). I should verify whether this is due to Colorado’s hard water, or not.
  10. After adding the water, turn off the heat, replace the lid and go to bed. The soap will take its sweet time to dissolve. Stir it every once in a while. This is a days-long process. It’s important to let the soap cool completely while you dissolve it in water. I find the soap takes longer to dissolve if the heat is on.
  11. Once the soap is completely diluted, turn the crock pot on again and bring the mixture to about 180F.
  12. Separately mix a 33% borax solution: 3 oz borax in 6 oz boiling water. As long as the mixture is hot, the borax will be dissolved in the solution. As it cools, borax precipitates out and you can’t use it in your soap. I found that heating the water on the stove and mixing the borax in the pot was the best way to keep it dissolved.
  13. You should use about 0.75 oz of borax solution per pound of soap paste. I used about 3 oz for this batch of soap. Too much borax will make your soap cloudy, and too little will make your soap somewhat drying.
  14. Add the essential oils after you neutralize the solution, but before it cools down. The overall color of the soap is amber, so adding other colorants should account for this. Use about 1 oz of essential oil per pound of paste. I don’t like too much scent in my soaps, so I generally round down.
  15. Let the soap cool. Once cooled, pour it into bottles or jars. Set aside in a cool place. Cure (also known as “sequestering”) for 1-2 weeks. Particulates should settle to the bottom of the jar by the end of the week. Discard those when you repour the soap into smaller bottles.
  16. Bottle the soaps and enjoy!