How To Make Cold Process Soap
Want to gain confidence in your DIY beauty efforts?
So if you really want to show your DIY prowess, learn how to make cold process soap!
As always, the draw of DIY beauty products two-fold:
- You control the ingredients so as to avoid chemicals and irritants.
- You save money.
Use what you have on hand to make a pretty cheap bar of soap that cleans beautifully.
Learning how to make cold process soap may seem intimidating. Yet once you get it, it’s a fairly simple process.
Before we dive into to the recipe, let’s go over basic soap-making terms and equipment.
Soap-making has a vocabulary all on its own. Here are some helpful soap-making terms that are good to know:
Fats are what you are turning into soap. This can take the form of butters (such as shea, cacao, or mango), liquid oils (such as olive, coconut, or sunflower), and hard oils (like tallow and lard). Many soaps are commonly made with a combination of fats, using different ones to achieve the type of soap desired.
Lye, or sodium hydroxide, is what makes fats become soap. Lye’s purpose is to saponify the fats into a usable cleaning product. Lye a highly caustic material and needs to be handled with extreme care and proper safety equipment. White vinegar is necessary to have on hand when using lye to neutralize the caustic on equipment.
Trace is the beginning of saponification. It happens when you blend the fats and lye together, getting a pudding-like texture to the soap. Cold process soaps require reaching trace after blending the fats and lye together.
Saponification is achieved when all the lye is changed, and all the fat is now “soap”. All the lye must be changed, or you risk chemical burns.
Herbs may be infused into one or more of the fats before adding to soap to change the properties of the soap. For example, infusing chamomile or calendula into an oil, then straining and adding to your soap recipe is great for soothing itchy skin.
Fragrances like essential oils can be added for smell. They are not a necessary addition, however. Unscented bars work just as well.
Colorants, like foods and additives, are another fun way to personalize your soap. Beet root powder, carrots, spirulina, activated charcoal, or spinach can all make a pretty, naturally colored bar of soap. (You actually can create a seafoam green soap with the addition of spirulina.)
Safety equipment is a must when making soap. Lye, when not handled correctly, can cause serious chemical burns on your skin. Safety first!
Eye protection — do NOT skip this. Safety goggles are found at your local hardware store. You must protect your eyes from lye!
Gloves — at a minimum, use common cleaning gloves. Gloves designed to protect you from chemical spills are the BEST choice, but they can be costly. Again, you must protect your skin from the lye.
If despite all your best efforts, you lye splashes on you, do NOT use vinegar on your skin. This can cause further chemical reaction. The best remedy is to rinse it off in plain, cool water for 10 minutes and then wash skin thoroughly to remove any residue.
Molds are nice but not necessary. I simply use a 9″ x 13″ glass dish.
Measuring cups and a scale are very important. Accuracy is key when measuring out fats, lye, and water. Too much lye, and you risk crumbly soap that can burn your skin. Not enough lye, and you risk very soft soap that won’t last long, nor provide you with bubbles.
A stick (immersion) blender is not a necessity, however it makes getting the soap to trace so much faster. You can always use a wooden spoon to stir to trace. It’ll just take a lot longer.
A wooden spoon is used for mixing the lye water with the fats, and can be used for bringing soap to trace. Wood is preferred over metal as the metal can have a reaction to the lye.
White vinegar is necessary when working with lye to neutralize the caustic on bowls, spoons, and measuring cups.
Cold Process Soap
To make cold process soap, you mix the fats and lye, bring it to trace, and then pour into a mold without cooking. Saponification comes over time, as the soap cures and hardens. The soap cannot be used for 4 to 6 weeks while curing to allow all the lye to change.
This process is great for making a shampoo bar, a beauty bar, or adding different colors, herbs and fragrances to your soap.
This recipe is great for beginners, as all the ingredients are easily found, and rather cheaply.
First, gather all your supplies. Make sure you have all the supplies before you begin. This recipe makes 4 or 5 hard soap bars, depending on the size of the cut.
Supplies (all must be weighed)
- 8 ounces (by weight) WFN Craft Oil
- 4 ounces (by weight) WFN Olive Oil
- 4 ounces (by weight) rendered beef tallow or lard
- 6.08 ounces (by weight) water
- 2.45 ounces (by weight) lye
How To Make Cold Process Soap
First fill your sink with hot, soapy water and add 2 cups of white vinegar for every 2 gallons of water. I just eyeball this amount.
Next, wearing your safety equipment, carefully measure out the lye and the water in separate containers. Glass is best to work with here, as metal bowls can cause a chemical reaction. If possible, work with lye outside, or near an open window, due to the fumes it can create.
Carefully pour the lye into the water. Do not add the water to the lye, as you can create a volcano that will have caustic chemicals spilled everywhere.
Gently stir the lye and mix with the water. You will see steam rising, and it will get very hot. Use proper caution, and a hot pad under the lye/water bowl. Stir until all the lye is dissolved. Allow to cool.
While the lye/water is cooling, measure out the fats.
Gently heat them until they are JUST melted. You do not want the fats and oils to be too hot, or your soap will not saponify. A good way to know if they are cool enough is that you have a tiny bit of solid fat chunks floating in the melted oils. At this point, turn off the heat and continue to stir for 2 minutes to finish melting and allow the oils to cool a bit.
Carefully pour the lye water into the melted fats and oils. Gently stir with the wooden spoon to mix.
Using the stick blender, or the spoon, stir until you reach trace. This can take as little as 3 minutes, or as long as 15 minutes, depending on the oils used. Olive oil will require longer time to reach trace, coconut oil less time.
Next, prepare your molds (or glass pan). Line with parchment paper or grease with cooking spray or a bit of coconut oil to help release the soap.
Once the soap has reached trace, pour into the molds. It will be like pudding texture, so be careful not to spill. If you want to add fragrance or colorants, this is the best time to do so. Stir in carefully to blend.
Tap the soap mold or your pan gently a few times to remove air bubbles.
Cleaning Up & Curing Your Soap
Place all equipment into the soapy vinegar water to neutralize the lye. Allow to sit there for 10 minutes.
Allow the soap to harden overnight, then remove from the mold and cut. Store in an open area, where there is plenty of circulation. Allow the soap bars to “cure” for 6 weeks before use. Rotate the bars every month or so, if desired to keep the air moving around. As they cure, they will harden even more.
Have you ever made cold-process soap? What herbs, fragrances, or colors do you add?
- Heather Harris