Sous Vide Infused Soap


Skip the store-bought soap and start making your own personalized lather, just in time for holiday gift-giving.


16.5 oz sunflower oil
7 oz coconut oil
5.5 oz potassium hydroxide (lye)
56.5 oz distilled water, divided
2 oz boric acid, mixed into 8 oz distilled water

Essential Oil

(choose 1 combination)
15 ml jasmine flower
15 ml Meyer lemon
7.5 ml vanilla and 7.5 ml lavender
7.5 ml coconut and 7.5 ml warm ginger



  • Sous vide circulator
  • Sous vide pouches
  • Vacuum sealer
  • Gloves
  • Safety goggles
  • 4-quart slow cooker
  • Sheet pan
  • Digital probe thermometer
  • Food scale
  • Stick blender
  • Potato masher (optional)
  • Pitcher


Prepping time: 15 minutes / Cooking time: 18 hours (excludes sous vide cooking)


13-15 6-oz bottles


  1. Put on safety goggles and gloves and place a sheet pan underneath a slow cooker.
  2. Measure ingredients using the scale.
  3. Pour the sunflower and coconut oils in the slow cooker and turn it to low.
  4. Allow mixture to reach 160°F (71.1°C).
  5. While the oils are heating up, add the lye to 16.5 ounces of distilled water in a pitcher and stir until dissolved. Do not add the water to the lye, because it may splatter and could irritate your skin. Be careful, because this mixture will get hot on its own and will make a hissing noise while dissolving.
  6. When the oils reach 160°F (71.1°C) in the slow cooker, slowly pour in the lye mixture while blending the ingredients with a stick blender. Continue blending for about 5 minutes.
  7. Continue cooking the mixture in the slow cooker for approximately 30 minutes or until it becomes an airy solid. Be careful because it can easily boil over onto the sheet pan. Turn the slow cooker off and let the mixture cool completely.
  8. Preheat a water bath to 160°F (71.1°C). Place the slow cooker mixture in a sous vide pouch, remove the air, and seal. Place pouch in water bath and cook for 6 hours.
  9. After the soap has cooked for 6 hours, pour the remaining distilled water into a pot and bring to a boil.
  10. Remove the soap from the sous vide pouch and place back into the slow cooker on high. Once the water has come to a boil, pour it over the soap.
  11. Put the slow cooker lid on and turn the machine off. Let cool overnight, or at least 6 hours. If you want to hurry things along, break up the solids using a potato masher—but nothing works as well as time.
  12. After the soap paste has completely dissolved in the water, the soap needs to be neutralized. In the slow cooker, bring the mixture to 180°F (82.2°C).
  13. Bring 8 ounces of distilled water to a boil. While the soap is heating, mix the boric acid into the boiling water to create the neutralizer. Stir well and make sure that it stays hot. If the mixture cools, the boric acid will fall out of the mixture and it won’t incorporate properly.
  14. Every pound of soap paste (the mixture before the water was added) requires 3/4 fluid ounces of neutralizer. The soap paste in this recipe weighs about 2.8 lbs, so you’ll need to add 2 fluid ounces of the water/boric acid solution.
  15. Mix thoroughly.
  16. The addition of too much neutralizer may cause the soap to become cloudy, so add slightly less than the math dictates.
  17. Let the soap cool. When the soap has cooled, you may add your fragrance of choice. If you like a very fragrant soap, use approximately 0.5 ounces (15 ml) of essential oils. Your soap may be cloudy after the addition of essential oils, but it will clear up in a day or two.
  18. Pour your soap in your favorite dispenser and enjoy.

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