Rosemary oil, scientifically known as Rosmarinus officinalis, is a volatile oil widely used in the pharmaceutical, cosmetic, and food industries due to its aromatic properties and strong antioxidant content. From medicinal aromatherapy applications to hair and skincare products, and even as an antioxidant preservative in food, rosemary oil finds use in various areas. Therefore, proper storage of this oil is critical to preserving its active components.
In general, essential oils rapidly oxidize and lose their properties when exposed to light, heat, and oxygen. For this reason, the storage temperature and environmental conditions of the oils are highly significant. Low temperatures can positively influence the rate of oxidation by slowing it down. However, extremely low temperatures—such as storing in a refrigerator—can alter the oil’s consistency and physical structure, making it more difficult to use practically.
Storing rosemary oil in the refrigerator can be a preferred method to prevent oxidative degradation. However, the potential adverse effects that may occur during refrigeration should not be ignored. Specifically, rosemary oil stored in glass bottles may be exposed to condensation when removed from the refrigerator, leading to contamination with water droplets. Over time, this can result in microbial contamination of the oil.
The ideal storage condition for rosemary oil is typically a cool, dark, and dry environment. The optimal temperature range is between 15°C and 25°C. Additionally, the oil should be stored in airtight containers to minimize contact with air. Under these conditions, the stability and efficacy of the oil's active ingredients can be maintained over a longer period.
Although rosemary oil is more stable in low temperatures in terms of oxidation, factors such as changes in physical structure and the potential risk of microbial contamination should be considered. In this context, storing the oil in a cool, dry, and light-protected environment—preferably in dark glass bottles—is also recommended by academic sources to maintain the integrity of its active ingredients.
Yes, it can be stored, but it’s not always the best option. The low temperature in the refrigerator slows oxidation, contributing to a longer shelf life. However, once removed, condensation may occur—especially if stored in glass bottles—allowing water to enter the bottle. This can lead to microbial contamination over time. The consistency of the oil may also thicken, making it harder to dispense. If you choose to refrigerate it, allow it to return to room temperature before use.
Sunlight can degrade the phenolic compounds and antioxidant constituents within the oil. As these compounds break down, the aroma, color, and effect of the oil may alter over time. Especially rosmarinic acid and similar beneficial compounds undergo photodegradation. Oils stored in light-colored bottles or exposed shelving deteriorate faster than expected. Using dark glass bottles helps reduce this risk significantly.
