Recently we had a customer ask us how to make their melt and pour soap firmer, so I have been busy in the blog kitchen doing some testing. I have three methods that I have tested to see whether or not they make melt and pour soap firmer. First things first, I made one bar of melt and pour soap that I did not change. I wanted to have something to compare my test bars to.
The first method I tested is adding salt. Salt is often added to cold process soap to make it harder, so why not add it to melt and pour soap? The ratio I used is 1 tsp of salt per 1 pound batch of melt and pour soap. I really had a hard time getting the salt to dissolve into the melt and pour soap. I tried putting it back in the microwave for 30 seconds, but it didn’t really help. I felt like I got some of it to dissolve, but after minutes of vigorous mixing, I decided just to pour it into the mold and see what happened. Inside my finished soap, you can definitely tell there is undissolved salt. If you try this method, I would recommend adding the salt to a small amount of water and allowing the salt to dissolve, then adding the water to your soap.
The second method I tested was adding Sodium Lactate, a liquid salt commonly used to make cold process soap harder and longer lasting. The ratio I used was 1/2 oz Sodium Lactate per 1 pound batch of melt and pour soap. I had the same problem with the Sodium Lactate as I had with the salt. It was not mixing into the melt and pour soap. So I popped it back into the microwave for 30 seconds, and then I had no problems mixing in the Sodium Lactate. The finished result was a little bit firmer than the original bar.
The third and final method that I tested was pouring the melt and pour soap into thin layers, reheating, and pouring again. Doing it this way gives you a bigger surface area, allowing more of the water to evaporate. I put a baking sheet inside a giant plastic bag so I could just peel off the soap, reheat it, and pour it again. Then I heated the soap and poured it onto the plastic-covered baking sheet. Once it was cool, I peeled the soap off the covered baking sheet and heated it again. I did this three times so that each time more water would evaporate from the soap. This method did eliminate some of the transparency of the soap. As you can see in the photo, it is semi-clear but not transparent.
In the end, I think the bar that ended up the hardest was the one that I poured into thin layers and reheated. I think this method works great at firming the bar as long as you are not worried about losing transparency. If that is an issue for you, I think the next best is the bar with Sodium Lactate.
I had a lot of fun experimenting with these soaps, and I hope this blog is informative to our readers.