When we started Apollo Olive Oil, we learned that light was bad for olive oil, and urged customers to keep our oil bottles out of the light. A few years ago, we were able to shrink-wrap the bottles in a completely opaque label sleeve. Now, a recent study from researchers in Perugia, Italy found that dark glass may not be sufficient to protect extra virgin olive oil from oxidation due to light exposure. Olive oil is more subject than other types of oil to oxidation from light because of its chlorophyll content. Actually, exposure to light causes more oxidation than heat or air does, when it comes to olive oil. Researchers found that after 180 days of exposure to lighting conditions similar to those in supermarkets, the oils in dark glass began to turn rancid. The study verified that an opaque coating like ours protected olive oil the best.