One of my readers recently asked me, “How long can I store olive oil for?” I wasn’t totally sure, so I looked it up in my handy Encyclopedia of Foods, which is edited by experts from the Mayo Clinic, Dole Foods and UCLA. I was shocked at what I found!
According to the encyclopedia, not only should olive oil only be stored for a few months after opening, but you should also avoid cooking food with Extra Virgin Olive Oil. This is because exposure to excess air, light or heat causes the fat to oxidize. When fat oxidizes, harmful substances called “free radicals” are produced that cause damage to our body’s cells.
Extra virgin olive oil is considered the highest quality olive oil. However, compared to other oils, has a relatively low smoke point (about 250 degrees F). This is the temperature at which it starts to smoke and decompose. Therefore, it is recommended to save extra virgin olive oil for salads, sauces and garnishes. Regular and light olive oil is better for cooking, as their smoke points are above 400 degrees.
Regarding the storage of olive oil, the Encyclopedia of foods recommends storing olive oil in a cool, dark location, and in a tightly sealed, opaque container for 1 year before opening or a few months after opening. They also report you can store in the refrigerator to make it last longer. (Note it may become cloudy, but this will not affect flavor, and the cloudiness will resolve when it is returned to room temperature.) They also report you can test olive oils freshness by smelling it. If it smells musty or fishy, toss it out.
So, how is this info going to affect how I use olive oil? I’m not sure yet. I do sauté food in extra virgin olive oil, but not usually at a very high heat, or in very great quantities. (I enjoy Pam Olive Oil spray, pictured right!) Free radicals are bad, but they are everywhere in our environment, and they are combated in our bodies by antioxidants found in fruits and vegetables (which I eat a lot of!). Olive oil has so many other health benefits, such as being rich in healthy monounsaturated fats, that I hesitate to use less of it or switch to another oil.
What do you think? How concerned should we be about cooking with olive oil, or aged oils?