Unlike wine, olive oil does not improve with age. However, because of its high level of monounsaturated fat and initially low oleic acid, Extra Virgin oil will last longer than other oils if properly stored. Enemies of olive oil's longevity are light, oxygen, time and temperature. Reducing any of these factors will increase the useful life of your oil and retain its peak flavor longer.
While it may look pretty in a clear bottle, oil should be stored in a dark colored glass bottle and kept in a dark place. Ultraviolet light, especially fluorescent lights can degrade oil more quickly. Besides being environmentally unfriendly, oil in some plastic containers can pick up unpleasant flavors. At il Fustino, all oils are sold in dark green glass bottles to protect them from light. We keep all oils in light-proof stainless steel tanks or in a darkroom.
The amount of air in the container will accelerate degradation. Keep oil in small bottles and tightly capped when not in use. We inject nitrogen into our fusti displacing all the air, so no oxidation can occur while the oil is stored.
Try to use oil 6 months after purchasing and buy no more than you will need. Label oils with the purchase date, so you know which are the oldest and use them first. Discard any oil that is older than one year and never combine older oils with fresher ones. We turn our inventory rapidly and purchase only recently pressed oils to insure freshness. All our oils come pre-labeled with the sales date and the type of oil.
You can store oil in the refrigerator without harming it. It can even be frozen without damage! However, cold oil has little aroma. If you are going to use it on a salad or to dip bread, let it come to room temperature. The ideal place to store oil is in your wine cellar at 57 °F (if you are lucky enough to have one) but you may forget that you have it if it is not stored where you keep your other condiments. If it is kept at 70°F (25°C), it will be fine. Just don't store it over the stove or refrigerator. Our oils are stored in a temperature-controlled darkroom until they are ready to be sold and then we only refill fusti 5 gallons at a time.