Hot Process
Soap Making Tutorial

Hot process soap making is very much like cold process soap making and even uses the same recipes.

The difference between the two methods is the addition of heat to 'cook' the soap in the hot method.

This cooking forces the gel stage to occur faster, evaporates more water and produces a harder bar of soap faster than the cold process method.

Be sure to read all of the instructions first before proceeding and have fun!!

Step 1 - Getting Ready.

Step 2 - Measuring the Base Ingredients.

Step 3 - Mixing the Oils and Lye.

Step 4 - Cooking the Soap.

Step 5 - Additives and Pouring Soap.

Step 6 - Cutting and Curing.

Step 1 - Getting Ready.

Before you make hot process soap, be sure that you're prepared and have everything you need. A little extra time spent on the planning pays off in the end.

1. Choose your location carefully.

- Your soap making area should be free of distractions, have an element (stove or portable), be in close proximity to your oven, have access to water and have a large, flat work surface.

2. Protect your area.

- Lay down a protective layer on your work surface. I use a vinyl table cloth. It's cheap, easy to wipe clean so I can reuse it, and oils won't leak through.

- Put down a rubber backed carpet if your floor needs protection.

3. Assemble all equipment and ingredients.

- Set up all your soap making supplies and ingredients in a manner that works for you.

- For this method of hot process soap making, you will need a crock pot in addition to your regular soap making equipment.

4. Prepare soap molds.

- Line your soap molds with butchers paper.

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Step 2 - Measuring the Base Ingredients.

When you're first learning how to make soap, it's best to limit yourself to just a couple of additives to begin with. As you become more familiar with making hot process soap, you will be more confident about adding in other techniques.

All the steps in these soap making instructions are important but with this step it is crucial that you pay particular attention to measuring accurately. Make sure you are familiar with your weight scale before you start.

Inaccurate measurements can produce lye or oil heavy hot process soaps which you will either have to re-work or throw out. Learning how to make soap is a lot more fun if you don't have to throw it out!! Make sure you get a good scale....it's the best investment you can make.

1. Measure additives and essential oils.

- Measure out any botanicals or colorant you will be using and place them in ramekins.

- Measure out any essential oils, extracts and/or nutrients that you are adding and place them in small sealed jars.

2. Prepare the lye solution.

- Measure out your water and place it in the juice jug.

- Before using sodium hydroxide, put on your safety equipment; goggles, gloves and long sleeve clothing.

- Measure out the lye and pour it slowly into the water stirring as you pour. Keep stirring until the lye crystals are completely dissolved.

- You will notice fumes being produced while you are mixing the lye solution. I hold my breath until the lye is dissolved and then leave the area for a few minutes until the fumes disburse.

SPECIAL NOTE: Always add the sodium hydroxide (lye) to the water. NOT the water to the sodium hydroxide. An unpleasant, violent reaction occurs if you do. Kind of like vinegar and baking soda is my understanding.

3. Measure base oils.

- Starting with the solid oils, measure each and place it into your crock pot that is set on low. As you continue to measure, the solid oils will melt.

- Once the solid oils have melted, add the liquid oils.

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Step 3 - Mixing the Oils and Lye.

This is the step where hot process and cold process soap making start to differ. There's no need to cool the oils with hot process soap making...great for those who hate to wait!!!

1. Combine lye solution and oil mixture.

- Slowly pour a thin stream of the lye solution into the pot of oils while using the whisk/stick blender to stir the mixture.

- Maintain a steady, strong stirring motion. Not so fast as to splash but fast enought to keep the mixture in constant motion. The idea is to get the oil, lye and water molecules to meet and combine to make soap. If you're using a stick blender, pulse for a few seconds then stir for a few seconds. Repeat.

- Make sure to stir thoroughly all areas of the pot. The mixture will turn creamy and opaque and then will begin to thicken.

2. Stir mixture until it begins to trace.

- Keep stirring until the mixture reaches a thick trace.

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Step 4 - Cooking the Soap.

Once the soap reaches a full trace, it's time to cook the mixture and force the gel. Below are some photos to show you what the different stages of the process look like.

1. The Cook.

- Put the lid on the crock pot and leave it to cook on low for awhile.

- The soap will heat up and start to bubble around the edges of the crock pot.

- Keep an eye on the soap and stir it down gently only if it starts to bubble over.

- The mix will begin to take on a clear vaseline like look. Once the whole mix has this look, you can test it to see if it is done. Take a small sample of the soap and rub it between your fingers. It should have a waxy feel. Test the soap by touching it to your tongue. Keep cooking....if it 'zaps' like a nine volt battery, it's not done.

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Step 5 - Additives and Pouring Soap.

Now is the time to add color, botanicals and scent to your hot process soap mixture.

1. Incorporating additives.

- Mix in any botanicals and extracts.

- Mica and oxides can be mixed with up to 1 Tbsp. per pound of warm glycerin or warm oil. This will help to make the colourant easier to blend in.

- Once the soap has cooled a bit, you can add the essential oils. Make sure to cool the soap to a temperature below the essential oils flash point. Flash point is the temperature that the oil will ignite and vaporize.

- You will have to work quickly while mixing since the soap may become to cool to place in the mold.

2. Molding the soap.

- Hot process soap is a lot like rebatching when it comes to molding. It doesn't pour. It is a thick goopy mass (like mashed potatoes) that must be scooped into the mold quickly. Make sure to tap the mold on the counter to get out any air pockets.

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Step 6 - Cutting and Curing.

Once your soap has reached room temperature it can be unmolded.

1. Unmolding.

- Remove the soap from the mold and take off the butchers paper. If you did not use a lined mold, you may find it easier to remove the soap by placing it in the freezer for awhile.

2. Cutting.

- You can cut the soap into bars right away.

- I use a soap cutter that requires you to push the soap block through a thin wire. This tool makes cutting soap blocks a dream. The building plans for this cutter can be found in Catherine Failors book "Transparent Soapmaking".

3. Curing.

- Once you have cut the soap into bars, they should be cured for a few weeks. The longer the cure, the milder the soap.

- There is some debate as to how soon hot process soap can be used. My feelings are that the cure time should be as long as with cold process (around 4 weeks) while others have said it's ready to go immediately. Since I haven't seen any scientific documentation showing this to be so, I've decided to stick with the longer cure. Though I will admit to having tested soap on many occasions long before it's cure is complete...I'm just impatient that way.

- Place the soaps in a single layer on a beer flat or tray lined with paper towel. Turn them regularily so that all sides are exposed to the air.

4. You're Done!

- Now that you have learned how to make hot process soap, it's time to plan the next batch!!