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Three bars of chestnut soaps lying flat, one bar standing up amidst autumn leaves and chestnuts
Angela Braun

Homemade Chestnut Soap (5 % superfat)

Learn how to make natural chestnut soap from foraged horse chestnuts! This beginner-friendly, sustainable soap recipe uses the natural saponins in chestnuts to create a gentle cleanser with a rich lather. Optionally, you can add chestnut powder for exfoliation.
This yields approximately 1400 g of soap.
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Prep Time 5 days
Soap-making 45 minutes
Total Time 5 days 45 minutes
Ingredients Equipment Method Notes

Ingredients
  

For the chestnut extraction
  • 1/3 cup chopped chestnuts
  • 500 ml distilled water
For the chestnut powder
  • 5 - 10 chestnuts
For the soap
  • 250 g coconut oil
  • 250 g olive oil
  • 200 g rice germ oil
  • 100 g sunseed oil
  • 150 g shea butter
  • 50 g cocoa butter
  • 330 g chestnut extraction
  • 137 g sodium hydroxide
  • 40 g chestnut powder optional

Equipment

  • 1 pot for melting the fats and oils
  • 1 heat-resistant container, about 500 ml for making the lye
  • 1 large bowl for mixing fats/oils and lye
  • 1 0.5-gram-precise scale
  • 2 thermometers one for the lye, one for the fats
  • 1 stick blender
  • 1 whisk
  • 1 spatula
  • 1 soap mould volume: 1.5 kg
  • Your personal safety gear!

Method
 

  1. Prepare the chestnut extraction by putting 1/3 cup of chopped chestnuts in a jar or bottle and adding 500 ml of distilled water. Let the mixture rest for 24 - 60 hours and strain it through a fine-mesh sieve.
  2. Prepare the chestnut powder (optional) by peeling 5 - 10 chestnuts (depending on the size) and either dry them for about 5 days in a well-ventilated area or until completely dry in an oven or dehydrator.
    Grind them in a food processor or coffee grinder and sieve the powder once or twice through a fine-mesh sieve.
  3. Put on your protective gear!
  4. Make the lye by adding sodium hydroxide to the chestnut extraction (never the other way round!)
  5. While the lye cools down, melt the fats and add the oils
  6. When the lye and fats/oils have reached a temperature of 40 - 42 °C (104 - 107 °F), pour the lye into the fats/oils (never the other way round).
  7. Stir everything well together with a stick blender, but make sure that you don't insert too much air.
  8. When traces begin to form, add the chestnut powder with a whisk.
  9. Pour the soap batter into a soap mould, cover it with greaseproof paper and insulate it by wrapping the mould in towels.
  10. Let the soap set for about 48 h before unmoulding it.
  11. Cut the soap in bars and cure it for 4 - 6 weeks in a well-ventilated space. Change the soap bars twice a week to make sure that they dry and cure evenly.

Notes

The soap bars can be stored in a cool and dry place for up to 2 years.