What to Do with Old Olive Oil
Once you've figured out how to tell if your extra-virgin olive oil is rancid, the next thing you're probably wondering is: Is there anything I can do with the oil just before that happens? Extra-virgin olive oil isn't cheap, and we all have a lot of other things on our minds, so even if we've purchased the freshest oil possible, we're all eventually going to find ourselves in this situation.
One great idea is to infuse it with flavors and freeze it, says Eryn Balch, vice president of the North American Olive Oil Association. She says the easiest way to do this is to simply pour the oil into ice cube trays and add whatever flavoring elements you like — whether it's some chopped lemon peel, minced garlic, or chopped rosemary — and place it into the freezer. Then, when you're ready to incorporate a burst of extra flavor into your favorite salad, pasta, or meat dish, simply pop out a cube.
Another idea is to create a blend with refined olive oil or another vegetable oil to increase the smoke point of the extra-virgin olive oil. This will allow you to fry with the olive oil without having it burn and it will give foods better flavor than by simply frying in vegetable oil alone. This, though, would have to be done fairly soon because once the oil goes rancid, the rancidity cannot be blended out.
Lastly, you may also want to consider baking with it. Extra-virgin olive oil can be used as a one-for-one substitute in any recipe calling for vegetable oil. Use it in cakes, muffins, and brownies to give them great flavor and an extra-moist and fluffy interior. While this is something you probably wouldn't consider with a freshly bought bottle because of the cost, it's a great idea for an olive oil that you're about to throw out anyway.
Will Budiaman is the Recipe Editor at The Daily Meal. Follow him on Twitter @WillBudiaman.