Glycerin is one of the most common natural ingredients in foods, pharmaceuticals, and cosmetic products, and when used correctly can have a preservation effect. However, it exists in these products for multiple reasons, and determining whether it’s used in safe amounts — especially when buying homemade products — is hard to pin down.
So how do you know when glycerin is a preservative? What is it and why is it used in food and skincare products? And how can you be sure glycerin is keeping you — and your food — safe?
Defining preservatives
Everyone likely has an opinion about preservatives, but there are many kinds that all have a specific purpose in their product. Preservatives were first utilized to prevent the growth of bacteria, molds and fungi. Without them, our food could go moldy, and our cosmetics could have irritating effects.
Most of these products have one key ingredient that makes them degrade quickly — water. Water is a breeding ground for bacterial growth, especially when left unused for a long time.
How does glycerin prevent mold?
Glycerin was first discovered in 1778 by a German chemist named Carl Scheele but wasn’t popularly utilized until much later.
In its most natural form, glycerin looks like a clear syrup and has a sweet taste like it too. Glycerin is considered a humectant, which means it keeps things moist as water does. Its sweet and preservation effects have made it key to many products across the food, pharmaceutical and cosmetic industry.
How to make glycerin?
Glycerin can be made or harvested in multiple ways. It can be produced from animals, plants or created synthetically in a lab. Vegans will be happy to know that most glycerin is produced from vegetables, choosing to harvest the needed substance from vegetable fats like coconut or palm oils. When mixed with lye and heated, the mixture creates glycerin.
When the fats are harvested from plants, glycerin-based products use the label “vegetable glycerin” and have all the same non-toxic properties as glycerin created in other ways.
Another form of glycerin is labeled glycerol, a purer form of the preservative, but has effectively the same properties.
Is it natural?
Seeing these properties, the USDA classified glycerin as a safe and natural preservative usable in products labeled “organic.” Most shoppers won’t find glycerin in your grocery store, although it can be made at home (click here to learn more: USDA PDF.)
Why is it in cosmetics?
Across the cosmetic industry, glycerin-based products are used in cosmetic products like lotion recipes and lip balms. It helps these products stay fresh and hydrated during their shelf life without spreading harmful bacteria. However, do mind the expiration date to ensure it’s free of bacterial growth!
In these cosmetic products, it can also create a moisturizing and soothing sensation in response to skin irritation.
Broad spectrum preservative
Like any natural ingredient, you need to make sure you’re using the correct amount in your mixture to get the effect you want.
With glycerin, the key is to ensure you’re using it in high enough concentrations to be classified as a broad-spectrum preservative. While the term is quite the mouthful, the term broad spectrum preservative exists because in smaller quantities most preservatives cannot defend against the thousands of types of bacteria that threaten your pantry or cosmetic products.
So certain preservatives are placed in products in higher quantities, or different combinations, to maintain long shelf life. These preservatives are considered to protect against a “broad spectrum” of bacteria.
The right recipe
In order for a product to be classified as a broad spectrum preservative when using glycerin, the recipe generally needs to contain up to 50% glycerin. However, too much glycerin can be potentially hazardous, so often manufacturers will do lab tests to ensure they’re using the proper amounts. When creating at home, be safe and ensure you’re using the proper recipe.
Bonus: Making glycerin at home
As it sounds, glycerin is easy to make at home. Some DIY types will create their own glycerin to mix with some dried herbs for their homemade soaps and cosmetic products that are just as effective over a long time as products from the store.
Glycerin can be created by rendering your chosen fat in a pot with water on a stove. Next, continue to heat the fat with lye and then add salt to the mixture to separate fresh soap from glycerin.
When used correctly, glycerin is a natural ingredient that can protect you and your loved ones with products that are natural, clean, and healthy.