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Can Peanut Butter Go Bad?

So you felt like having a peanut butter and jelly sandwich only to find that your PB has passed the date on the label. Should you proceed with making that sandwich, or find something else to indulge in? How long can you eat peanut butter after it expires?

If peanut butter sandwiches aren’t a staple in your menu, sooner or later you will run into PB that’s near its date. And if that’s the case right now, it’s time to learn a bit about going bad and shelf life of this popular spread.

Or perhaps you’re wondering if “all natural” peanut butter requires refrigeration after opening the jar. Or why it doesn’t require refrigeration in the first place. In that case, we need to talk about storage of peanut butter so you can make the most out of what you’ve got.

First off, let’s tackle the big question of whether or not PB goes bad and how to tell if it’s off.

Peanut butter jar
Peanut butter jar

Can Peanut Butter Go Bad? How To Tell If Peanut Butter Has Gone Bad?

Like with other somewhat similar foods, like mustard or ketchup, you can say that peanut butter is bad for one of two reasons. The first one is actual spoilage, so the product is no longer safe for consumption. The second one is that its quality has degraded and you just don’t want to eat it anymore. Let’s cover both in a bit more detail.

When it comes to spoilage, it’s quite uncommon for peanut butter to spoil. PB is mostly fat, and as such it’s not that easy for any bacteria to live and thrive in there. That’s why it has such a long shelf life, even after opening, and why most producers don’t require you to refrigerate the spread (more on these topics later). So as long as you do a decent job of storing your jar, its contents shouldn’t spoil, even months past the date on the label.

But if you notice any growths on the surface or sides, any black specs, or something similar, discard the jar. Same thing if the spread has noticeably changed its texture, or developed an off or rancid odor. When it comes to consistency, one thing to remember is that oil separation is normal in peanut butter, and it’s not a sign of spoilage ([PBC]). Just stir that peanut oil back in.

Peanut butter oil on top
Peanut butter: oil on top

Now let’s talk a bit about quality. Like most food products, this nut butter degrades over time. That’s why many producers state explicitly for how long you can keep their PB once opened. The changes are gradual and impossible to notice if you were to taste the spread every day. But they add up, and after a few months that peanut butter definitely isn’t as good as it was when you opened the jar for the first time.

Maybe the taste is somewhat lacking, or it dried out a bit, and it’s not easily spreadable anymore. And at a certain point, you might prefer to throw it out instead of eating it, even though it’s technically safe for consumption. If and when you do that is entirely up to you. So if your PB does not hit the spot anymore, don’t feel bad about discarding it. It’s past its prime, and there is no point in finishing it for finishing’s sake.

Knowing that, you probably want to know how long, realistically, peanut butter keeps its quality. Let’s talk about that.

Peanut butter: no oil after stirring
Peanut butter: no oil after stirring

How Long Does PB Last? How Long Can You Eat Peanut Butter After It Expires?

To start off, each jar of peanut butter has a best-by or best-if-used-before date on the label. So if you check the label of your Skippy or JIF PB, you’ll surely find one. That date informs you how long, at the very least, the sandwich spread should retain quality. When it comes to how long the period between production and that best-by date is, it varies, but it’s usually between 9 months ([APB]) and a year. And as long as the jar stays unopened, its contents should keep quality for at least a couple of months past that date. An unopened jar keeps the spread safe from any bacteria and fresh oxygen, so the deterioration process is slow.

Once you first open the jar, fresh air gets to the PB, and the degradation process accelerates a bit. That’s why some producers state specifically for how long their PB keeps quality upon opening.

Peanut butter: best by date on label
Peanut butter: best by date on label

For example, Peanut Butter & CO says you should finish the jar within 6 months ([PBC]). Others ask you to merely observe the date on the label.

In short, for best quality, try to finish the jar within half a jar of opening. The longer it stays open, the worst the taste will be. But it’s not like it will become flavorless or something like that a week or month later. It most likely will still be quite tasty 9 months after you pop open the jar.

So, for how long past the date on the label will the peanut butter be okay? It’s impossible to tell, as it depends on quite a few factors. The most important ones are how you stored it, and when did you open the jar. In general, if it’s only a couple of months past the best-by date, you stored the container properly and opened it a few months earlier tops, the quality of the peanut butter should be at least okay. Just check for signs of spoilage I described earlier, and if there aren’t any, give it a taste and decide if it’s good enough or not.

Oatmeal topped with peanut butter
Oatmeal topped with peanut butter

How To Store Peanut Butter? Do You Need To Refrigerate It After Opening?

Unopened peanut butter is shelf stable, so you just need to make sure it sits in a dark place away from any sources of heat, and you’re good to go. If it’s in the pantry, or in a dark cupboard in the kitchen, it’s up to you.

What puzzles many people is whether or not one should refrigerate opened PB. Generally, it’s best to keep peanut butter that you regularly use at room temperature ([SK]). And it’s true for any peanut butter, even those “all-natural” ones. Or at least I’ve never seen one that asks you refrigerate it after opening. In other words, natural peanut butter doesn’t go bad if not refrigerated.

Just opened jar of peanut butter
Just opened jar of peanut butter

And in all honesty, nobody really knows what a “natural” peanut butter even is, because there’s no formal definition or a set of requirements. But even one-ingredient PBs don’t need refrigeration, so those “natural” ones shouldn’t need it either. But that doesn’t mean that peanut butter likes heat, so make sure that the storage place is relatively cool, and definitely away from the stove.

But all of that doesn’t make refrigerating peanut butter useless. If you want to preserve the flavor for longer, the fridge can help you with that ([SK]).

(The same is true for peanuts, which you can read about in Do peanuts go bad? article.)

The only downside is that the sandwich spread gets firmer, and it’s not that easy to spread anymore. But if you use PB only from time to time, storing it in the fridge might be the way to go for you. Especially if going through an entire jar takes you a couple of months.

Peanut butter in overnight oats
Peanut butter in overnight oats

In a Nutshell

  • keep peanut butter at room temperature if you use it regularly; go for the fridge if you use it occasionally
  • peanut butter usually doesn’t spoil, but its quality degrades over time, so at a certain point you might want to discard it for quality reasons
  • PB lasts a long time in good condition, often months past the date on the label