Keep at dark for storage, avoiding any exposure to direct sun light.
Optimum storage temperature is +18 °C to +20 °C (+64 °F to +68 °F). Refrigerating or freezing does not harm any type of olive oil. But olive oil expands about 2-4 % by refrigeration or freezing and may shatter the glass bottle if bottle head space is not sufficient to compensate the expansion.
Refrigeration or ambient temperatures less than +15 °C (+59 °F) May causes partial crystallization at extra virgin type olive oils. Crystallization effect is less in blends of refined olive oils.
This effect is harmless and when olive oil container stored at room temperature of maximum +25 °C (+77 ° F), when olive oil temperature exceeds +16 °C (+60 °F), olive oil crystallization disappears and returns to golden clear color without any quality loss.
Virgin and Extra Virgin Oils must never exceed +25 °C (+77 °F). Otherwise nutritionally valuable vitamin E is degraded.
Oxygen inside air may cause olive oil to become rancid. This starts from the top surface where air exposure is continuous. This reason the necks of the bottles are narrow, surface exposed to air is minimized. When the rest of container will not be used, say within a month, it is better to transfer the olive oil to a smaller container and fill till to half neck and seal the lid tightly to prevent air penetration.
Olive oil easily absorbs foreign odors and smells carried by air. You must keep olive oil in a tightly seal able container and tightly seal the container after every use and stow away from synthetic or natural odors, fuels, chemicals, exhaust gases, organic debris, etc.
Differences of temperature due to night and day, rainy days or climate changes may cause condensation of moisture in air on the walls of container as pure water droplets. When the container is tightly sealed, outside moisture shall not affect olive oil. However temperature drops by night may cause condensing of water droplets on outside of olive oil container. If container is tin, rust may start and if there is a paper label, paper may absorb the water and swell and deform and may partially peel off. The corrugated carton boxes containing olive oil containers can absorb the condensing moisture and become softer and not be able to carry the containers and may be easily torn by slight forces.
To avoid this situation, the ambient relative humidity must be less than 60% and cartons should be stowed about 10 cm (4”) above the ground on pallets and cartons should be covered with cloth or plastic in high ceiling spaces.