This recipe shows you how to make glycerin soap base. It makes a fun, moldable base (purged of all lye and oils) that you can make into many shapes and colors.
By now most all of you know I’m a soap maker. I have a small business that makes more than 400 bars a month and it’s still growing. I sell a lot of soap at the tailgate markets in the summer and I always have people asking for glycerin soap base. It’s still a common myth that glycerin soap is milder and better for you. That can be true in some cases, but a good hand-crafted cold process bar of soap contains just about as much glycerin.
Let’s take a look at how glycerin is made and then explore my favorite, recipe for how to make glycerin soap base.
How Glycerin is Made
Glycerin is a by-product of soap making. It can come from other sources, but soap making is by far the most common source. When you combine lye and water with oils, it saponifies and becomes soap. (Check out our tutorial on making cold process soap.) Actually, what you end up with is ⅔ soap and ⅓ glycerin. The glycerin is then usually taken out and sold to other companies such as fertilizer and explosives manufacturers. If you refine the solid soap, add sugar and alcohol, and skim off the impurities, you get glycerin soap base. Let’s take a look at the entire process.
How to Make Glycerin Soap Base
This is a basic recipe for how to make glycerin soap that is clear. It takes a bit of practice to get it clear. My first batch turned out cloudy and I think it was because the soap base I made wasn't dissolved enough. Take your time and be patient!
- 14 oz vegetable oil, lard, tallow, or other oil
- 5.5 oz coconut oil (find organic coconut oil here)
- 8 oz castor oil (find organic castor oil here)
- .75 oz safflower or sunflower oil (find organic safflower oil here or organic sunflower oil here)
- 4 oz lye, also called 100% sodium hydroxide (find it here)
- 5 oz filtered or distilled water (find the best water filtration systems here)
- Cover work surface with newspaper. Always use gloves and safety goggles when handling lye. (Learn all about lye in soap making.) Have vinegar on hand in case lye spills or splashes occur.
- Measure water into a heatproof container. Measure lye and slowly add to water, stirring until dissolved. (Never add water to lye.) Allow lye water to cool to 150°F.
- Mix all of the oils together and heat to 135°F - it's easiest to use a slow cooker for this. Add the lye water to the oils in a slow steady stream.
- Bring the mixture to a trace, or when it looks like vanilla pudding. An immersion blender works best for this.
- Keep the heat at medium for a few hours, much like making crock pot soap. When it reaches the gel phase, it will look translucent like petroleum jelly. Stir once in a while, but not all the time. If it gets too thick, you can use a potato masher. I have a stainless steel one I use just for this.
- After a few hours, take a bit of the soap and try to dissolve it in a cup of hot water. If it dissolves, you can move on. If it stays in a lump or has oil floating on the top, you need to "cook" it more. Leave it for half an hour and try again. If it's ready, then add:
- 13 oz alcohol - 70% or higher (NOT rubbing alcohol)
- 3 oz liquid glycerin (find it here)
- Be very careful as alcohol has a low flash point and can start on fire. This is why I prefer the crock pot to the stove for heating. You may need to mash the soap up some. Do a bit at first, then do more in a little while. If you mash too much at once, you may get a lot of suds. This process can take a few hours, so be patient.
- When the soap is all dissolved, there will probably be a few particles floating on top. These are impurities and must be removed. Skim them off and throw them away, or you can place them in a jar, cover with hot water, and use for dish soap.
- When the soap is fully dissolved combine 8 oz sugar and 5 oz water and boil until the sugar is completely dissolved. Do not leave any crystals undissolved. When it is totally liquid, pour into the soap base. Stir and cover, then cool to 145°F.
- Now you can pour it into a mold. I use a glass cake pan. Cover with plastic wrap and let sit for a week or so. When it is clear (it may take a week or two) then cut it into pieces and store in a glass jar.
Using Your Glycerin Soap Base
Once you make glycerin soap you’ll see how fun it is to work with. All of the lye and oils have been worked out, leaving you with a very moldable base. It can be made into a wide array of shapes and colors.
- Prepare your molds. Set them on a flat surface and get your fragrances and colors ready.
- Figure out how much soap base you need. An average bar of soap is 4 ounces. Many molds tell you how many ounces the mold will hold. Use a bit more as some will remain on the melting container and spoon.
- Place as much soap base as you need into a heatproof container to melt it. I use a pint jar. Place the jar in a pan of hot water to melt, stirring with a spoon occasionally. When it is all melted, take the jar out of the water and place on a cloth. Add a few drops of food coloring if desired. Stir well. Add more if needed. Next, add the essential or fragrance oil, a few drops at a time. A 4-ounce bar should have about 10 drops of scent, give or take a few drops. Add any dried herbs you may desire, about a teaspoon for a 4-ounce bar.
- When you have the desired amounts of additions to your soap, pour into the molds. If the base cools too much and gets chunky or stiff, just remelt it and stir. Let the molds sit until the soap is completely cooled. Larger molds will take longer.
- When cool, gently pull the mold away from the soap and push on the back side of the mold to release. Wrap soap in plastic wrap or wax paper. You must wrap it right away or it may collect moisture from the air and bead “sweat” on the surface. While this is a sign of good soap, most people don’t like the look of it and it is hard to use.
- Clean up is easy. (After all, it’s soap you’re cleaning off your supplies.) Just soak the molds in hot water, rinse and dry well.
A Few Notes on Making Glycerin Soap
- 70% alcohol may be hard to find. Don’t use rubbing alcohol, you will never get rid of the smell! I use a 75% Everclear which is available in most areas. If not, ask at your local liquor store. They can recommend what may work. Keep it clear and unscented.
- Alcohol can catch easily, so be cautious!
- Silicone molds work well because they peel off the soap easily.
- These instructions are for clear soap. Add some titanium dioxide or zinc oxide powder to get a white soap that will produce pastels when colored. (Find titanium dioxide here or zinc oxide powder here.)
- Keep herbs ground well and always use dried herbs.
- White sugar produces the best results. Raw sugar can be used but your soap will be more amber colored.
Do you know how to make glycerin soap base? How did your batch turn out?