In this post, we’re sharing some basic guidelines on herbal preparation shelf-life. We’ve even made a free printable for you so you can have these guidelines handy in one place. Feel free to download, print, and store this chart in your herbal journal or on the inside of your bathroom cabinet (or wherever you store the majority of your herbal preparations) so you can easily reference it the next time you have a question about herbal preparation shelf-life!
Oil-based herbal preparations are those that are comprised mostly of lipids, such as herbal salves and infused oils.
While microbes can multiply in oil once contaminated, microbes are not the main threat to the shelf-life of oil-based herbal preparations — it’s oxidation (rancidity). Oil rancidity naturally occurs with time, and can also occur due to improper storage and usage. We’ll discuss these three factors that affect herbal preparation shelf life later in this article. Water is another substance that can impact the shelf-life of herbal infused oils as it can lead to microbe growth within your oil. While this is normally not an issue if dry herbs are used, it is a concern for herbal oil infusions made with fresh herbs.
The shelf-life of oil-based preparations made with dried herbs varies greatly depending on the oil you choose, therefore, herbal infused oils and salves have a shelf-life that ranges from 6 months to 3 years. For infused oils that oxidize easily, you can add antioxidant products like vitamin E and rosemary oil extract to help extend shelf-life a little longer as these products have been shown to slow the process of oxidation (Riaz & Rokey, 2012).
When making herbal preparations, you want to be mindful that you are working in a clean environment and with clean materials. The cleaner your hands, surfaces, and utensils are the less chance for bacterial contamination of your herbal preparation. Using dry herbs as opposed to fresh herbs can help decrease the chance of bacterial growth due to the presence of water in fresh plant material. Avoiding overheating of herbal preparations, particularly herbal infused oils, can increase the chance of oxidation. Also, when storing any liquid preparation for an extended period of time, shelf-life can be extended by straining the liquid through a coffee filter several times to thoroughly remove plant sediment (Green, 2000).