Hot Process Soap Making Frequently Asked Questions - Wholesale Supplies Plus
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Hot Process Soap Making Frequently Asked Questions

This article answers questions related to the slow cooker method of making hot process soap.

HP (Hot Process) Soap Making – General Questions

What is HP Soap?
HP is "hot process" soap. It is called hot process because the saponification process is acellerated with heat. The is soap made similar to cold process soap ~ using oil/fat/nut butters, lye and water. The ingredients are brought to trace. The soap is then exposed to heat and "cooked" through the saponification process, usually in a crock pot or double boiler. At this point fragrance and color added and the soap is place into a mold. The hot process somewhat changes the appearance of the finished soap, but allows the soap to be fully saponified and immediately ready for use within a few days.

How is HP different from CPOP?
CPOP (Cold Process Oven Process) Soap is brought to trace, colored, fragranced and put in the mold - and only then is heat applied to speed saponification. It has the same basic appearance and function as CP.  

HP Soap is brought to trace and then heated. Only after it has been heated are color and fragrance added, and is it put in the mold. It has the same basic function as CP, but generally a less dense and more "fluffy" appearance and texture.

What type of recipe is suitable for use in HP?
Theoretically, any recipe can be created using the HP Soapmaking Method. However, some recipes in which ingredients trace and saponify very quickly (for instance, those with a high concentration of saturated oils like palm and coconut) will be somewhat tricky as they will go through the stages of HP very quickly. Recipes which trace and saponify very slowly (like olive oil "castille" soap) can take longer to go through the stages of HP, but you will save weeks of curing time versus CP'ing them. 

How do I HP my recipe?
First, you make your recipe as usual and bring it to trace (light trace is just fine). Next, you put the soap into a crock pot on "High", which brings the mixture to somewhere above 200 degrees Fahrenheit.  

When using HP to make soap, you need to observe the soap go through three distinct stages. Note that the appearance of these stages will depend on the oils in your recipe. The three stages are: 
  1. Separation. In this stage, it can look as though your HP has gone horribly wrong, as you will see solids separating from your liquid content. Don't worry - just keep occasionally stirring, and wait for stage 2.
  2. Coming Together and Rising. All of a sudden, your soap will stop separating, come back together, and then start rising. The soap can rise a LOT during this stage. So, keep a close eye on it, and stir vigorously to get the air out of it and bring it back down. You do not want it to overflow! Wait for stage 3.
  3. Greasy Mashed Potatoes, or Vaseline.In this final stage, the soap will stop rising and settle down a bit. Stir it every few minutes, and you will notice that it starts looking less bubbly and more glossy (a lot like Vaseline, actually!) as it finishes saponifying. You will know it has finished saponifying when you test the pH. After the pH is 8-10, you can add color and fragrance. You can then mold the soap.

What type of pot and utensils should I use for cooking my HP?
The crockpot seems to be the most popular cookware for HP Soapmaking. You can use it on "Low" or "High", since they both reach the same temperature, just at different speeds. You might want to use "Low" with recipes which saponify quickly or those with ingredients which burn easily (like goats' milk or honey) and "High" with all other recipes. Note: After you have thoroughly cleaned and scrubbed the crockpot from HP Soapmaking, you can safely use it for food because you are using it to make soap, and all of the lye is cooked out of the soap.  

If you choose to use a container other than a crockpot to make HP Soap, make sure you use one made of stainless steel or one that will not interact with the active lye. Some soapmakers use a stainless steel double boiler to make their HP.  

All of the utensils need to be heat and lye resistant made of stainless steel, wood or silicone. 

It is best to use a crock pot or double boiler with a glass lid. Keep the lid ON while heating the HP Soap unless the recipe has excess water that you wish to have evaporate (in which case you will not use the lid). Most recipes are best heated with the lid on to keep them nice and moist. 

What type of mold will I need for HP?
You will want to put your finished HP Soap into the mold when the soap is still rather warm, pliable, and easy to work with. Therefore, you will want to use molds for your HP which can comfortably handle temperatures near 200 degrees. Wood and silicone molds work well for this, as do some plastics. Thinner plastics will warp when exposed to the heat of HP so, be careful when using your favorite plastic molds.

What type of colorants can I use with my HP?
HP Soapamaking allows you to use a more broad range of colorss because the color is added when the pH of the soap is between 8 and 10. FD&C; colorants (which normally turn brown in the presence of lye) can be used in HP, as can micas, oxides, ultramarines, glitter, herbs and spices.

What type of fragrances and essential oils can I use in my HP?
One wonderful aspect of HP Soapmaking is that it is a bit fluffier than standard CP and CPOP, and it absorbs fragrances very nicely. 

When can I use my finished HP Soap?
It's best to leave the finished HP in your molds for the first 24 hours, to allow it to become hard enough to cut it without marring or warping it. Once it has been cut, it will probably benefit from another two to five days of "drying out" before usage. If you use your soap too quickly, it will dissolve rapidly – so, use your best judgment to determine when it looks fully hardened and ready to use! Enjoy!

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