How Long Is Peanut Butter Good For Once It's Been Opened?

Peanut butter is one of the most delicious and culturally admired spreads. After cracking open a jar though, you may be wondering — does peanut butter expire? The short answer is: yes. But to determine how long the nutty spread will stay good after it's opened, the answer depends on a couple of factors, such as where you plan on storing it, and whether it features natural or commercially processed ingredients.

Peanut butter already has a longer shelf-life due to its high fat and low water content, which prevents and greatly delays microorganisms from growing. This isn't to say that PB can't eventually go bad. While it's always smart to be mindful of the "best by" date printed on jars, there are ways to ensure a longer shelf-life. 

A jar of natural peanut butter is good for a month in your pantry whereas one with preservatives can last up to three months. However, both will stay fresh for two to six months longer (depending on the spread's ingredients) if refrigerated after opening.

How natural ingredients vs. preservatives affect peanut butter's shelf-life

While they may taste similar, there's a major difference between "natural" and traditional jarred peanut butter. The biggest and perhaps most noticeable difference between the two can be spotted in their appearance. Commercial AKA "no-stir" peanut butter like Jif and Skippy come pre-mixed or blended and are ready to consume. These spreads use stabilizers and preservatives to considerably extend the product's shelf-life and are safe to store in your pantry for up to three months after opening. However, if you don't plan on consuming an entire jar in a 12-week window, pop it in the fridge to keep the spread good for an additional three to six months. 

On the other hand, natural peanut butter typically consists of only peanuts and salt and nothing else — and has a much shorter shelf-life. Some variations include other ingredients like vanilla, honey, or other natural sweeteners but largely preservatives are not included. Unlike commercially processed peanut butter, natural jars will likely have a layer of oil at the top upon opening that needs to be thoroughly stirred before digging in. With no additives, there's nothing to keep the oils and solids from separating and it can get messy. An open jar of natural peanut butter can last a month in your pantry but most are recommended to be refrigerated where they'll be good for two to three months. 

How to know if your peanut butter has gone bad

If a jar of peanut butter in your household doesn't stick around for more than a week after opening it, you've maybe never had the occasion to wonder if it's gone bad. But, for those who savor the nutty spread and use it more sparingly, it's a fair question.

On the jar's packaging, you'll notice a best-by date, however, peanut butter is one of those miracle foods that, if stored properly, can be eaten past its expiration. In fact, an unopened jar of commercial peanut butter can survive an entire year past its best-by date and will still be completely safe to eat. Unopened jars of natural peanut butter will last two to three months past the printed date — or three to six months if refrigerated. That of course changes once it's been opened, so it's best to only lift the seal once you're actively planning to use the spread.

If you're consuming a slightly older jar of peanut butter, it's important to review the quality. Firstly check for a change in smell. If you open up a jar and notice a sharp, pungent, or bitter aroma, it's likely passed its prime. Appearance is another great indicator. If the once light, smooth, and creamy treat has turned dark, dried out, or grown mold, it's obviously time to discard. Lastly, a sour or rancid taste is the final clue that it's time to swap for a fresher option. It's important to keep food safety in mind, so if your PB has any of these noticeable changes, throw it out and crack open a new jar.