This is a great question. You might notice that pure extra virgin olive oil is often sold in dark glass bottles. This is so that light and heat have trouble getting in! Light and heat may potentially oxidize extra virgin olive oil, giving it a strange bitter taste and reducing its health benefits. I keep my olive oil in a cool, dark cupboard away from heat and sunlight, but not in the fridge because I don’t like how it drizzles on my salad if it’s too cold!  However, refined olive oils do not need to be kept away from heat and sunlight, as they are much more stable.