There are too many variables that affect the shelf life. Even the cosmetic industry has widely varying guidelines. The FDA does not “require cosmetic manufacturers to print expiration dates on the labels of cosmetic products. Voluntary shelf-life guidelines developed by the cosmetic industry vary, depending on the product and its intended use.” Read the rest of the FDA article on shelf life here.
Previously, I had recommended 3 months shelf life based on my own personal experience over the last several years. Noting the many factors that can affect shelf life and that I cannot guarantee the ingredients you use and the cleanliness of your equipment, I am no longer recommending a shelf life. Instead, I will just present what I do and don’t do to get my personal lotions to last 3 months:
- I don’t sterilize. I just wash all my equipment with hot soapy water just as I do with all my cooking utensils. I don’t even sterilize the containers I use to store my homemade baby foods. The only time I sterilize is when I’m canning food.
- I can food but I don’t can my lotions. You can try using the hot water method of canning where you submerge the sealed jar in hot, boiling water. Just a suggestion.
- I don’t use distilled water but I always boil my tap water for at least 2 minutes. Here in Austin, I feel perfectly comfortable using tap water for cooking, drinking, and lotion-making. If you feel different about your water source, then use bottled distilled water.
- No matter how much lotion I make at a time, I always package in containers no larger than 8 fluid oz (by volume). I don’t refrigerate the lotions I’m currently using but I keep all the other unused ones in the refrigerator.
- I use bottles with flip top lids for lotion. Lotions in bottles keep longer than in wide mouth jars since you are less likely to contaminate the lotion. I do not use pumps. They are hard to clean and keep clean.
- I use wide-mouth jars for thick creams. It is easier to clean the container afterward.
- I don’t use herbal infusions. They significantly shorten the shelf life. Note that your end product’s shelf life is only as stable as your least stable ingredient. In general, oils are more stable than aqueous ingredients. Using oils that are more stable and possess antimicrobial and/or antifungal properties only retard the growth of bacteria and mold, not prevent it.
- I don’t use natural preservatives unless one of the essential oils I’ve added has antimicrobial properties. I no longer recommend grapefruit seed extract. See note above.
So, if you sterilize all your equipment, use bottled distilled water, use the more stable ingredients, and always keep your lotion in the refrigerator, then you’ll probably achieve longer shelf life than I have presented. Conversely, using less stable ingredients like herbal infusions and aloe vera and not properly cleaning your equipment will shorten the shelf life. Keep in mind that the minute you open a packaged product, whether it’s food or skin care, commercially manufactured or homemade, the product is subject to microbial contamination. It’s in the air and all around you. Also, just because a product is well packaged with preservatives added, commercially done or at home, doesn’t mean it’s free of bacteria (although antimicrobial preservatives does prevent the growth). Note all the product recalls – food, cosmetics, bottled water, etc… Cosmetics, just like food, are not expected to be aseptic.
Think of homemade skin care the same way you think of cooking and preserving food at home. You don’t have to follow the complicated industry guidelines of manufacturing to lengthen the shelf life. You can keep it simple and just make smaller amounts to be used up in a short period of time. Just like with food, there are many ways you can increase the shelf life without adding synthetic preservatives, albeit at the expense of added complexity and being more time consuming. It is up to you to decide how much or how little effort you want to put into your process. Without sterilizing, I can literally make 3 months’ worth of lotion in less than 15 minutes. In general, just like food, if it smells rancid, looks discolored, or has mold, toss it. Basically, use common sense and your own judgment. One thing I do urge you not to do is add synthetic preservatives (though even some ‘natural’ ones like GSE are controversial). It defeats the whole purpose of homemade cosmetics!