Basic Hot Process Soap

Basic Hot Processed Soap Tutorial

A hot process soap recipe that will release easily from plastic molds – by TJ Currey

soap making instructions and recipes
Hot-Processed Soap (also known as HP soap)

This is a soap making technique right out of the dark ages when they used to boil soap in vats over open fires. Heat is applied (using a double boiler, microwave, oven, or crockpot) after the trace stage to accelerate saponification. The soap is thoroughly cooked until saponification is complete.

While hot-processed soap is easily removed from lined wooden molds, it’s extremely difficult to get out of regular plastic molds. In fact, the word that comes readily to my mind is “impossible.” HP soap comes out on the sticky side at first until it is exposed to air for a few days. In other words, it likes to stick to the mold. I had even tried pretreating the molds with silicon sprays, Pam, olive oil, etc. Nothing worked. I don’t know how many times I’ve completely demolished a poor defenseless mold – its only crime was that it would not let my soap go!!!

There is hope!
Here is a recipe I have developed that will make it possible to easily remove hot-processed soap from plastic molds.


15 oz. Palm Oil (not to be confused with palm kernel oil)
5 oz. Coconut Oil
2 oz. Sesame Oil (if you don’t like the strong smell of sesame oil, try finding a refined/odorless version. If all else fails, Rice Bran Oil will work in a pinch.)
2 oz. Shea Butter
1 oz. Castor Oil
3.49 oz. Sodium Hydroxide (6% superfat)
9 oz. Distilled Water (No discount as this is a small soap recipe. If you are making a larger batch, you can discount the water by 20%)
1/2 teaspoon of Borax dispersed in water before adding lye -optional. I add the borax as it is a natural water-softening salt. It’s my belief that this will help the soap stand up against hard water.


Once the soap has finished saponifcation, let it cool for approximately 20 minutes, stirring occasionally. Allowing the soap to cool helps prevent fragrance or essential oils from “flashing off” – this happens when the soap is hotter than the evaporation point of the fragrance oil.

Before adding the fragrance, add approx. 1 oz. of Sunflower Oil and stir it in. This will cool the soap down a bit more and make the soap a bit more pliable and wet. Don’t worry about calculating that 1 oz. of Sunflower Oil into your recipe – all this is doing is cushioning the soap in the soap mold, and it will make the soap easier to pop out. The extra oil will eventually evaporate or meld with the soap within 24 hours of unmolding.

Start spooning the soap into your plastic molds, a little at a time – put the first spoonful in and then tap the mold against the counter several times to disperse any air bubbles. Once the mold is full, place a piece of plastic wrap over it and gently use your fingers and the palm of your hand to move the soap where you want it – make sure it fills the entire cavity of each mold.

Put on your patience hat and wait 5-8 hours before unmolding your soap. Gently press on the bottom of each individual cavity until you can see an air pocket begin to form between the soap and the plastic mold. Follow that air pocket around with your fingers, making it bigger and bigger. Voila! The soaps pop right out! If for some reason this doesn’t work, pop the mold into the freezer for 1/2 hour, take out and leave sitting on the counter for 5-10 minutes, and try again.

Additional Notes: I have found that other soap recipes will work well being molded IF and only IF a larger ratio of solid-at-room-temperature oils is used. Olive Oil tends to make soap sticky and impossible to move from a mold unless you let it sit there for 2-3 weeks! Choose from Crisco, Palm, Palm Kernel, Coconut, white odorless cocoa butter (if you don’t want the chocolately smell), lard, tallow, Shea Butter, Mango Butter, etc., making those oils a good 80% of oils used. Add other liquid-at-room temperature oils sparingly – a bit of Castor for bubbles, a dash of Sesame, Sunflower, Olive, Sweet Almond, Apricot Kernel, etc. And don’t forget to add that extra 1 oz. of Sunflower Oil AFTER the cook – I found this step might make or break this technique.