Why Soap Never Spoils But Your Face Cream Does

[00:00:00]You could leave this bar of soap for years in the bathroom and no mold would grow in it. While if you take this face cream right here that is homemade, if you leave it in the counter without any preservatives, it will grow mold within a few days. And then you would risk putting something with mold on your face. But why is that? Why is it that soap does not need any preservatives, but a hand cream or a face cream does need preservatives, otherwise it will have microbial growth. The answer comes down to two main parameters and soap denies them both. While hand cream, mm, not really. But first, quick context here. Microbes are not the enemies. We actually use microbes in our everyday life for many different applications. We use them to produce insulin that saves the lives of millions of people. We use them to produce wine, bread, pizza, beer. And they are even used to produce valuable bioactive molecules for the skin care industry.

[00:01:00]So, these are basically the good microbes. The problem is when the bad microbes grow in your products that you're going to put on your skin. For example, this right here is a bioreactor. A bioreactor is a system that is highly controlled to perform fermentations. The fermentations that are used to produce skin care molecules that add a lot of value to the industry.

[00:01:20]The fermentations that are used to produce medicine that save the lives of millions of people and the fermentations that are used to produce flavor ingredients that are used in our everyday products. And the parameters you can control in a bioreactor is basically steering, oxygen, pH, temperature, feeding media and so on in order to optimize the conditions to achieve the best result possible. So, microbes have been used for centuries to make bread, pizza, wine, beer, kombucha, fermented foods and so on. And whether those microbes grow on your skin care products comes down to two main parameters, pH and water activity. So, microbes basically need a livable pH. They need a good pH in order to grow. And the pH of 9 or 10, which is the pH of a soap, which is a highly which is alkaline, it's not a great environment for any microbe to actually grow. But, this is not the main reason why microbes don't grow in soap. pH is not the main reason.

[00:02:28]The main reason is water, and specifically, what we call water activity. What is water activity? Water activity is basically how much free water is available for microbes to actually use. A cured bar of soap that has been cured properly, and during curing, all basically water evaporates, a cured bar of soap has very low water activity. There's almost no free water in order for microbes to grow inside.

[00:02:55]While a hand cream [clears throat] or a face cream, they are made with minimum 70 to 8% water. And not only that, but the pH is not alkaline. The pH is a very good pH for mold to start growing inside. And if you would like a free PDF that shows you how you can make six skin care products from sensitive skin soap, body soap, dish soap, lip balm, deodorant with only very few ingredients, and without the need of preservatives, then I want a formulation, and I will send to you as soon as I see your comment. And the same happens with other skin care products.

[00:03:32]For example, let's say you want to make uh lip balms or deodorants. Lip balms do not contain any water. So, it's basically a combination of coconut oil, shea butter, or beef tallow, some olive oil or jojoba oil, and beeswax to basically bring the structure all together. Now, there is no risk of microbial growth in a lip balm. The only risk is that your oils might oxidize, that your oils might go rancid. But, this has nothing to do with microbial growth, and in order to troubleshoot that, we add a bit of vitamin E. Vitamin E is basically an antioxidant. It helps with preserving your oils and butters.

[00:04:15]Same exact thing with deodorants. They don't contain anything that contains water. Always depending on what recipe you use, of course. And, an important disclaimer here, I am talking about solid cold process soap. If you are making liquid soap, liquid soap is actually made with oils like olive oil or coconut oil or castor oil and lye, but in liquid soap, we use potassium hydroxide. We do not use sodium hydroxide. In solid soap, we use sodium hydroxide. Basically, potassium hydroxide leads to a softer type of paste, and in order to convert it to liquid soap, you need to add water. You need to dilute with water. And there, you do have some higher risk of microbial growth. Also, the pH is not as high because you have diluted with water, and water has a neutral pH, so the pH of the whole product actually goes down. But, here I'm talking about solid cold process soap, and this, the beauty of it, is that it's self-preservative. And then, using preservatives themselves is a whole other topic, so you have to use them.

[00:05:30]There are certain preservatives that are also organic certified, and those are the most desirable ones. There are certain preservatives that do not work in certain products, so it's also important to use the right ones. And if you found this video useful, remember I have an ebook that shows you how you can go from basically someone who just copies recipes without understanding why and why they add what they add to someone who basically designs their own recipes based on their own goals. It contains all this information plus 15 tested recipes from soap making to skin care making like shampoo, conditioner, deodorants, creams and so on. It has helped more than 300 soap makers so far and I would love to hear what you have to say about it. So, thank you so much for watching this video and I'm looking forward to seeing you next time.