How to Make Quick-Cure Hot-Process Soap
Homemade Soap: You Don't Have to Wait for a Month for This Soap to Cure
Homemade soap usually needs to cure for a month before you can use it—longer if you want a nice hard bar of soap that will last. But there is a method called hot-process soap making that speeds up the time it takes the soap to cure.
Heating the soap cures it quickly, making it safe to use in only 3 days to a week. Heating the soap will create harder, more long-lasting bars.
Use a large enamel or stainless steel roasting pan for the final heating. The large size of the roasting pan prevents a build up of too much heat. A roaster with a vent is good but not necessary. A lid is a must.
Use your regular soap recipe and method to make the soap. Homemade soap cannot be a slap-dash creation. The fat to lye proportions must be calculated according to a formula for optimum results. For a recipe, detailed instructions, and safety precautions, see How to Make Soap at Home.
Hot-process soap is sometimes a bit marbled, and quite pretty in its own way. If it looks crumbly or dry, it has been heated too much and you need to remill and add more water and oils. (Remilling instructions are at the bottom of the page.)
One problem with making quick-cure, hot-process soap is that the heat of the soap can destroy the scent of the essential oils you add for aroma. You may have to add a bit more of the oils than you would in a regular batch of soap in order to maintain a strong enough scent.
How to Make Soap - A Quick Review
- Assemble all ingredients and materials
- Cover and protect counter tops and self (apron, goggles or glasses, gloves)
- Measure and combine water and lye. Always pour the lye into the water and never the reverse which can cause a dangerous reaction.
- Ventilate the area when you combine the water and lye as it creates dangerous fumes.
- Preheat oven 180 - 200 degrees Fahrenheit.
- Line bottom of oven with aluminum foil in case of spills
- Measure solid fats, melt on low heat in deep enamel or stainless steel pot.
- Measure and add liquid fats
- Both fats and lye solution need to be the same temperature (about 110 degrees F) before mixing
- Slowly pour lye solution into the fats and stir
- Mix with hand blender until trace (it becomes the consistency of pudding)
- Add colorants. Do not add essential oils until later (heat destroys the aroma)
Hot Process Soap Making
For this batch, I used a bit less than a tablespoon of powdered Cat's Claw Bark which has healing properties. I added some cinnamon as well. You can see that before cooking, the soap was a lovely light brown color. Some colorants darken with cooking and drying and that is what happened with this batch as you can see from the final product. How you use colorants can tricky. That's where your own creative adaptations come into play.
- Pour soap mixture into roasting pan
- Place lid on roasting pan and place in preheated oven
- Check after 20 minutes
- Remove lid, tilting away from you for safety
- Stir and replace in oven
- After 30 - 40 minutes in the oven, the soap will look shiny and translucent with little pools of glycerin on top
- Stir gently, scraping bottom and sides of pan to insure even cooking
- As soap cooks, it will curl toward the center from the edges of the roaster
- Soap will come to resemble applesauce
- While soap is cooking, grease your mold with olive oil in preparation to receive soap mixture
- I add a splash of water and a splash of olive oil so that the soap does not dry out. Stir in quickly and return to roaster so that it does not lose too much heat.
- After an hour, when the soap mixture begins to look like mashed potatoes, you can remove it from the oven
- Stir it again and add essential oils. Remember that heat can destroy the aroma so you may want to make the soap smell a bit stronger than desired in the end product.
Homemade Soap - Curing the Soap Quickly
- Scoop soap mixture into prepared mold. Prepare the mold by greasing the bottom and sides with olive oil.
- Drop the filled mold onto table and run a knife through it to remove air pockets
- Cover with plastic wrap
- Cover with towels
- Allow to cool for 6 - 24 hours
- Cut into bars. Wetting the knife with hot water makes cutting easier.
- Cure for 3 - 4 days. I often wait a week so that it hardens off
- Trim off the edges. The sliced soap looks nicer
- Use the trimmings to make balls of soap or remill
- Set out the soap to cure on a rack (not aluminum). Let air curculate.
Test the Soap
Wearing gloves, wash hands with the cooled soap. Does it act like soap? Does it produce lather?
Tongue test - touch your tongue to the soap. If it buzzes, wait a week more.
If it doesn't seem right after a week, remill the soap, adding a bit more water and fats.
To Remill Soap
If you have extra shavings you can remill it. Of course, if the soap has already cured, you will only have to wait for the newly remilled soap to harden.
- Cut or shred soap into very tiny pieces.
- Place in glass or Pyrex container with a bit of hot water.
- Mix well.
- Heat a few seconds in microwave.
- Stir. When mixture is wet and gloppy, put into greased mold.
- Slice when set.