How To Tell When Your Olive Oil Has Gone Bad

If you think your olive oil is one of those bulk pantry purchases that can sit for ages without going bad, we have some unfortunate news for you. While highly refined cooking oils like canola and vegetable can last for over a year in your pantry, good olive oil is a different creature. Extra virgin olive oil in particular is actually a fresh ingredient, being pressed from olives with minimal adulteration (ideally), and it begins to degrade as soon as it's made. Once the bottle you buy is opened, it starts going bad even faster, and without even realizing it, you may have been using rancid or spoiled olive oil. Even worse, "best by" dates are not very useful, as they don't actually say much about how recently your olive oil was produced. That leaves you and your senses as the last line of defense for figuring out if your olive oil has gone bad.

Smell and taste are your two biggest tools here, as olive oil won't visibly change much as it goes bad. Olive oil that is still good should smell fresh and fragrant. While oils can have different notes, taking a whiff of a little olive oil that has been poured into a glass should give you fruity or sharp notes. Olive oil that has gone bad will have a distinctly waxy smell, which may remind you of crayons. Worse yet, it may even smell similar to meat that has gone bad.

If the smell test doesn't do it, you can test your olive oil by tasting it. There's no risk because, while rancid olive oil won't taste great, it won't make you sick either. Like the smell, spoiled olive oil may taste waxy or of plastic. The most obvious sign will be a pronounced bitterness or sourness, as opposed to a lighter more peppery flavor or a musty taste. You can also tell by the mouthfeel: Good olive will be rich and luxurious, but rancid olive oil will tip over into a more greasy and waxy texture.

To avoid your olive oil spoiling, you should buy in smaller quantities, especially nicer extra virgin olive oils that you will be using primarily to drizzle and dip. While olive oil can last up to 18 months on the shelf unopened, remember that this date starts from when it was packed, not when you bought it. And once you open your olive oil, you've only got three or four months to use it all. Ideally, to use olive oil at its best, it should be consumed within one month to six weeks. It's also best to purchase olive oils that are in dark glass or opaque bottles, and store it in a dark place, as exposure to light will shorten its shelf life. But if you are buying good olive oil anyway, none of those precautions should be a challenge.