5 Surprising Foods You Should Keep in the Refrigerator
1. Natural Peanut Butter
Natural peanut butter is peanut butter in its purest form—in most cases it's just ground-up peanuts and maybe a dash of salt. Because of this, natural peanut butter acts a little differently than "regular" commercial peanut butter—in natural peanut butter, the oils from the peanuts can separate from the solids, something that doesn't happen with regular peanut butter thanks to the addition of hydrogenated oils—and you should treat it a little differently too.
If you don't plan on finishing your jar of natural peanut butter within a month or so, or if you live in a hot climate, consider refrigerating it. The oils in the peanuts can go rancid if it's not kept cool over a long period of time. If the label recommends refrigerating after opening, follow the instructions. (Also, if your peanut butter develops mold, toss it—because peanut butter is processed without preservatives, it's at high risk for mold, according to the USDA.) If you're concerned about spreadability because your peanut butter is hard from being in the cold refrigerator, let it sit out at room temperature for a bit before spreading.