Does Peanut Butter Go Bad? How Long Does It Last?

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Although we can’t imagine anyone being able to hold onto a jar of peanut butter long enough to question if it’s still good, on the off chance that you’ve found one that escaped your attention, we’re here to answer your questions: does peanut butter go bad? How long is peanut butter good for?

Whether you like your peanut butter smooth or chunky, it will last around six to nine months unopened in the pantry. Once opened, you can still enjoy your peanut butter for two to three months stored in the pantry or six to nine months in the fridge.

Despite being a very thick paste, peanut butter is a dry product, in that it has very low water content. That fact, combined with the high oil content, make it a poor host for bacteria and mold. Although it’s unlikely to go bad due to microorganism growth, it can go bad due to oxidization.

Peanut Butter Shelf Life And Expiration Dates

Because peanut butter can last for a long time, best by dates are just a guideline. Your peanut butter can stay in good condition long after this date has come and gone if stored appropriately.

In 1922, Joseph Rosefield patented the process of churning peanut butter to reduce the risk of oil separation. This process disperses the oil evenly with the peanut particles and keep the product fresher for longer periods of time.

peanut butter

Most commercially packaged peanut butter has been churned and is unlikely to separate, reducing the risk of it becoming rancid.

  • Smooth/Creamy/Crunchy Peanut Butter – These commercially prepared peanut butters have preservatives that help prolong their shelf life. Unopened, they will be best quality stored in a cupboard for six to nine months, but should still be edible for up to a year past the printed best by date. Once opened, if stored correctly, they’ll last up to three months in the pantry or three to four months on top of that in the fridge.
  • Natural Peanut Butter – Natural style peanut butter lacks the preservatives that generic, commercial peanut butters possess. Unopened, you can expect them to stay good for around two to three months in the pantry, or three to six months in the fridge. Once opened, we recommended you keep them in the fridge, where they will last around five to six months.
  • Homemade Peanut Butter – Homemade peanut butter is simple and wholesome, lacking the preservatives of commercial brands. We recommend you store it in the fridge, where it should stay good for three to six months.

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How To Tell If Peanut Butter Is Bad

Bacteria and mold are an unlikely concern, no matter what the use by date says. This is because of the high oil, low water content – an inhospitable environment for both nasties.

However, the high fat content of peanut butter makes it prone to spoiling due to oxidization. This process can cause flavor and odor changes that make your product inedible.

When peanut butter sits for any length of time, the oil will start to separate from the butter. This is not an indication of spoiling, just a natural process. Simply stir the jar to bring it back to that delicious, spreadable consistency.

An exception to this rule is if there is more oil in the jar than there is butter. This may indicate that your peanut butter is either about to spoil, or already has. In this case, we think it’s safer to throw it out.

Here’s a few tips to help you find out if your peanut butter is still good to eat.

  1. Texture. Peanut butter should be soft and creamy. Old peanut butter will dry out and become hard. If you find this is the case, there’s no hope for your peanut butter and it’s best to dispose of it.
  2. Color. Peanut butter that has turned bad may have changed color and become a darker shade.
  3. Smell. Oxidization will cause peanut butter to develop a bad odor. If your peanut butter smells like anything other than peanuts, throw it out.
  4. Taste. As with the odor, bad peanut butter will be detectable with a tiny taste test. If you pick up any unpleasant or strange flavors, we recommend throwing it in the trash.

Can Old Peanut Butter Make You Sick?

Unless your peanut butter is contaminated by other substances which can potentially grow bacteria or mold, it shouldn’t make you sick, even when rancid. If you’re concerned, follow the steps above and check for any unusual colors or textures on the surface.

Eating rancid peanut butter won’t make you sick, but will not be enjoyable to eat.

How To Store Peanut Butter

The biggest threat to a jar of peanut butter is exposure to oxygen and light, which break down the molecular structure of the fat and cause it to go rancid.

Keeping peanut butter air-tight is critical to safe eating. Fresh peanut butter will separate, increasing the risk of it going bad.

Before opening, store-bought peanut butters can be stored in a cool, dark cupboard. After opening, they will still last in the pantry, but retain the goodness and flavor for longer in the fridge.

Remember to always screw the lid on tightly after use to avoid oxidization, and use clean utensils when scooping peanut butter out of the jar so you don’t compromise its longevity by contaminating it.

Does Peanut Butter Need To Be Refrigerated?

Popular peanut butter manufacturer Skippy recommends keeping their peanut butter at room temperature for optimal spreadability, although they do state that it will last longer in the fridge.

Homemade peanut butter should be refrigerated immediately, although because it lacks the hydrogenated oils that keep it soft and spreadable, it will go hard. You will need to remove it from the fridge around thirty minutes before use.

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Really, it depends on how quickly you can get through a tub of peanut butter. If you know you’ll use it up within a month or two, and store it correctly, best to leave it in the pantry where it will stay soft and spreadable.

However, if peanut butter is just a rare treat, keep it in the fridge where it will last you many months.

Written By Tara Williams

Tara is a food writer that has been editing and authoring articles for KitchenSanity since its founding. Her writing offers personal experience from experimentation with food and recipe creation. If you’re looking for simple tips, she will make your journey in the kitchen straightforward with a dash of fun.