Because yes, coconut oil can go bad
I always assumed that since it's shelf-stable, coconut oil can't go bad. Boy, was I wrong. Coconut oil can spoil, and believe me when I say that you'll know when coconut oil has gone rancid. Your once-beautiful, translucent white coconut oil will turn a pale yellow, and it'll get all chunky, almost like curdled milk. Rancid coconut oil has a strange smell. Oh, and those green or brown dots on the top of your old coconut oil? That's probably mold, and if you find it, your entire jar of coconut oil is totally unusable and needs to be tossed, which is a shame because coconut oil can be expensive. So what's the best way to store coconut oil in order to extend its shelf life?
The good news is that coconut oil has a naturally long shelf life: about two years. If you don't remember exactly when you bought that last jar of coconut oil, don't worry. Most jars of coconut oil in the United States come labeled with a "Best By" date, so you know when it's time to replace your stash.
The other bit of good news—or bad, depending on how you look at it—is that there really aren't any special tricks to storing coconut oil correctly. You just have to keep it a room temperature in a sealed, ideally airtight container. That's because oxygen will break down coconut oil quicker than even heat will.
But heat isn't necessarily a bad thing for coconut oil storage, and if your coconut oil turns into a liquid, that doesn't mean it's gone bad. Coconut oil has a relatively low melting point—about 76°F, according to experts at Nutivia, which manufactures coconut oil—so it will almost definitely turn to liquid on your shelf in the summertime. And though you might be tempted to store your coconut oil in the fridge, that actually makes it harder to use because the coconut oil turns rock hard when refrigerated.
Really though, the best way to keep mold from growing on your coconut oil is to seal it up tightly and use it up quickly. Given that there are so many great ways to use it, that shouldn't be much of a problem.