Homemade soaps, cosmetics, and other personal care products are just some of the latest trends to hit the streets. Making these products at home ensures a controlled environment, where you select the ingredients and you know exactly what’s going into the product and how it’s made. This can be very beneficial for many people, however, it’s equally as important to understand the process and a few key steps to ensure your products are safe.

We have posted several articles in the past about testing for microbes in homemade personal care products, and the importance of preservatives, avoiding contamination, and low microbial counts. However, testing the pH of these products is another topic altogether. So today, we’re looking at the process of making homemade soap and why testing the pH is important.

Dangers of Soap Making

So what scares people the most when making soap? LYE! Lye is a chemical compound known as sodium hydroxide, and it is highly corrosive. Lye creates a strongly alkaline solution when dissolved in water, and it can cause a number of problems, including chemical burns if it comes in contact with skin. It can also be highly flammable, or could boil or splatter if large amounts of lye are dissolved.

So why use such a harsh chemical as one of the main ingredients in soap? The other main ingredient is fat, and when fat and lye are combined in the right amounts, a chemical reaction called saponification occurs. The end result is soap with glycerin.

Safety Precautions

We’re not going to lie, lye can be very dangerous to work with, but with the right safety precautions, you’re well on your way to making a great batch of soap!

It’s important to wear goggles and gloves any time you’re dealing with lye and while handling the soap, until it tests non-caustic with a pH strip. So how do you know when it’s no longer caustic?

Lye is always caustic in flake and liquid form, and is no longer caustic when it is no longer lye. Makes sense, right? So then how do we know when it’s no longer lye?

In the soap-making process, you use a certain amount of lye and a certain amount of fat or oil. When the lye and oil are combined and saponification occurs, the result is soap. However, this reaction doesn’t happen instantaneously. It takes some time to complete, and you don’t want to jump the gun when working with this material.

Once the oil and lye have been mixed together and blended until they trace (thicken), the mixture is typically poured into a mold and insulated so the chemical reaction can continue. Depending on the process (hot or cold process), the time for the chemical reaction to complete can vary.

Testing the pH of Soap

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With cold process, your soap will be solid in about 12 hours and ready to be removed from the molds for testing. You should still be wearing gloves until you’ve tested the pH and proved it’s no longer caustic. To test, dab a bit of distilled water on the surface of the soap. Use your glove to smear the water around, making a paste with the soap. Using our pH 1-14 test strips, test the paste. If your strip reads between pH 7 and 10, the soap is no longer caustic and is safe to touch.

With hot process, the soap will gradually take on a waxy appearance while it’s over the heat. After a while, stir the soap and it should look like waxy mashed potatoes. Using a similar process as above, make a paste with the waxy soap and a bit of distilled water and test the pH. Again, it should register between pH 7-10 to be safe. At this point, the soap is safe to touch and use.

Sodium hydroxide has a pH of 14, and lye has a pH of 13. Again, it is extremely alkaline. Thus, when testing the pH of soap, you will see a gradual move towards a more neutral pH of 7. If your soap is still too caustic to touch, the pH will be between 10 and 14.

So don’t let lye scare you. With some proper safety precautions and testing measurements in place, you can successfully and safely make a great batch of soap. For a few fun soap recipes, check out our Pinterest Board!