Olive oil oxidises over time. The process of oxidation is accelerated by heat, light and oxygen. We recommend if you are not going to use the C60 in olive oil straightaway you put the bottle in a sealed light proof container and deep freeze the oil. This excludes the oil from the factors which would deteriorate it. When you come to use the oil you can take it out and let it thaw at room temperature. We believe this way you keep your oil fresh.