Unless You Eat Peanut Butter Fast, You Should Consider Storing It In The Fridge

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Many people never take a glance at the expiration date on a jar of peanut butter because they go through it so fast that it never has a chance to spoil. Yet, those who only enjoy the spread occasionally may want to consider that it can indeed go bad. Instead of letting it languish in the pantry until you are ready for a PB&J, consider storing it in the refrigerator — especially natural varieties.

Whether it's natural or a processed brand like Skippy, the oils within peanut butter can facilitate bacterial growth over time. Processed brands protected by preservatives maintain a long shelf life of six to nine months in the pantry before exhibiting signs of spoilage — if they remain unopened. However, after the lid comes off, they only have about two to three months before they need to go.

Some recommend that natural peanut butter should be refrigerated as soon as it arrives home because it doesn't contain these preservatives and only lasts for roughly a month after opening. That may seem like an adequate amount of time to use it up to most people, but if you consume the spread sparingly, the fridge is a better place to store it for the longest shelf life possible. Putting it in the refrigerator can extend its usefulness by three to six months. Still, there are other factors to watch out for that can affect the quality of peanut butter.

Even if you choose to store it in the fridge, things can still go awry with peanut butter. One common mistake people make is slathering jelly onto a piece of bread and immediately dipping that same knife into a jar of peanut butter. But jellies and jams typically have high sugar content and some bacteria have a sweet tooth. A portion of that sugar may find a new home in your savory spread, and unwelcome microbes might come along with it. 

Another factor that can increase the shelf life of peanut butter, regardless of where it's stored, is making sure the lid is closed tightly after every use. Exposure to air can cause foods to oxidize, which can result in spoilage. Peanut butter — even if it is loaded with preservatives — is no exception.

When you store all-natural varieties in the refrigerator to extend the shelf life, one hitch is that the solid portion will have a firm, unyielding texture when you attempt to stir the separated oil back in. You can pry some out and let it warm at room temperature until it becomes spreadable, or you can melt peanut butter in the microwave. However, avoid using any plastic in the microwave because there is no such thing as microwave-safe plastic — containers like these Pyrex Sculpted Glass Mixing Bowls work much better. The timing will vary depending on how soft you want the peanut butter to be, but it will be considerably faster than letting it sit out.