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How to Make Cold Process Soap

This handmade soap recipe will show you exactly how to make a batch of cold process soap at home.


  • Kitchen scale


Oil Materials

Lye Materials

  • 78 grams sodium hydroxide (NaOH)
  • 215 grams filtered/distilled water room temperature


  • Weigh and measure every ingredient ahead of time. It is imperative that items are weighted and measured precisely.
  • Wear gloves and safety goggles, and keep your workspace clean - lye can burn skin.
  • Heat the oil ingredients slowly in a stainless steel pot until you reach a temperature of 115 degrees.
  • Pour the room-temperature water into a large pyrex measuring cup. Stir, and SLOWLY add the pre-weighed lye. It's important to note that you will add lye to the water, not the other way around.
  • Stir until dissolved. Then place the glass container in an ice bath and cool to 115 degrees.
  • When the oils and lye mixtures are both at 115 degrees, slowly pour the lye into the oil mixture while rapidly stirring in circles.
  • Stir until the mixture becomes thick, and similar to the texture of pudding.
  • Add in the botanicals and/or essential oils - see the blog post for ideas.
  • Pour the mixture into molds (I use 1L milk cartons), and staple the tops shut. Then, wrap the molds in a towel and set on top of the fridge for 48 hours.
  • Unmold the soap and cut into even sections. Then, place the bars on a wire rack and let them cure for 3 weeks.
  • Buff with a cotton cloth, and wrap to give as gifts or use yourself!