Hot Process Soap Making

Step by Step Instructions

Popular with commercial soap making operations, hot process soap making is the technique of taking the soap to trace - then applying continual heat for 1 ½ to 2 hours until the soap has fully saponified - then thinning the soap with a bit of alcohol and pouring into molds.

This process enables the soap maker to pour into plastic molds without having to rush before the soap gets to a thick trace and is unmanageable. It means the soap maker does not have to worry about insulating the soap after pouring into molds - as they do with a cold process batch - because saponification is completed while on the heat. Neutralized soap is also gentle on fragrances, dyes and does not discolor herbs or flowers like cold process soap making will. Fragrance oils - which sometimes seize cold process soap by bringing it to trace too quickly - will generally work in hot process soap making.

• Have a second large pot (like a large canning pot) ready with water to create a double boiler effect when your soap making pot is placed inside.
• Make your soap as usual. Bring soap to trace. Ensure that the double boiler’s water is at a slow boil. (Do not place the color or fragrance into soap at trace. Wait and place it into soap after lye is neutralized. Colors and fragrances will be truer.)
• After trace, place the soap pot into the pot with water, creating a double boiler. Cover to retain heat and moisture.
• Cook your soap for 1 ½ to 2 hours, keeping the water in the bottom pot at a slow boil. Stir occasionally to ensure mixing and heat distribution. The soap should begin to have a slight translucent look. This is a sign that the soap is neutralizing.
• After approximately 1 ½ to 2 hours the soap will be neutral. This is the time to add any dye or fragrance. If the soap seems too thick to work with then thin the soap with a bit of Isopropyl alcohol or Vodka.
• If splitting the soap into smaller batches for different colors or fragrances then ensure that each batch remains hot. The soap will thicken quickly as it cools.
• Spoon soap into molds, tapping the molds lightly to remove any air pockets.
• If some of your soap does harden before it is poured into molds it can be re-melted using a double boiler.