How should essential oils generally be stored to maintain quality?

Essential oils should be stored in a cool, dark place to maintain their quality and extend their shelf life. This is because light, heat, and humidity can cause essential oils to degrade or lose their potency over time.

When essential oils are exposed to sunlight, as mentioned in one of the options, the ultraviolet light can lead to chemical changes that can diminish their therapeutic properties. Storing them in a warm area can accelerate evaporation or alter their chemical composition, and humidity can lead to condensation, allowing for potential contamination or dilution of the oils.

Using an airtight container also contributes to better preservation, keeping out moisture and external factors that could compromise the oils' integrity. Thus, a cool, dark environment is ideal for safeguarding the valuable characteristics of essential oils.