Does Peanut Butter Go Bad?

Peanut butter is a very popular sandwich spread in a few countries. And it’s tempting to think that it lasts forever. So, does peanut butter go bad?

We expect the shelf life of peanut butter to be pretty long, and it certainly is. But can it really go bad?

Similarly to most other foods, peanut butter can spoil, but it happens very rarely. It can go bad if it’s been contaminated somehow. If it wasn’t, you should remember that it loses its taste over time.

Keep in mind that its shelf life (the time when its quality is best) depends mostly on how you store it. If you store it properly, you should be able to eat or use it before it even starts to change its flavor.

How To Store Peanut Butter

Storing peanut butter is easy. The first thing you should remember is that the jar of peanut butter should always be closed with its lid when not in use. Peanuts (and therefore peanut butter) contain a lot of oils (fat), so oxygen can alter the nut butter’s taste.

This process is called rancidification – oxygen degrades fat’s structure which changes the flavor and smell of the product. The longer you expose peanut butter to air, the worse its taste will be.

When it comes to unopened store-bought peanut butter, keep it in a cool, dark place, preferably in the pantry.

Peanut Butter French Toast Sandwiches
Image used under Creative Commons from Bobbi Bowers

Once you’ve opened the container, you can still store it in the pantry if you plan to use the contents of the jar within a couple of months. For prolonged storage keeping the opened peanut butter in the fridge is the better option.

Opened peanut butter at room temperature slowly loses its flavor. When you transfer it to the fridge, the process continues, but it is significantly slowed down. The only downside of storing peanut butter in the refrigerator is that it becomes much firmer. And that means it doesn’t spread quickly and easily anymore.

If you make your own peanut butter and you don’t use any stabilizers, the best bet is to keep it refrigerated.

How Long Does Peanut Butter Last

Probably all peanut butter jars have a ‘Best By,’ ‘Use By’ or a similar label. That’s just the manufacturer’s information that the product should be of best quality for such period of time.

It doesn’t mean that it’ll go rancid or taste awful after that time. It rarely does. Unopened peanut butter can last for months or even years after the “best by” date, depending on how much preservatives it contains.

Opened peanut butter, if stored in the fridge, can stay fine to use for at least a few months past the date on the package.

If you want to know how long is peanut butter good for after the expiration date, there isn’t a straightforward answer. It depends on its ingredients and how you store it.

Making peanut butter at home
(credit: Irene Kredenets)

When it comes to homemade peanut butter, the shelf life depends on the recipe you use. In most recipes, authors mention how long it lasts.

If you don’t add any perishable ingredients to your homemade peanut butter, it should last at least a month, probably much longer. If you were looking for a quick homemade peanut butter recipe, check out this one.

 PantryFridge
Peanut Butter (Unopened)“Best By” + 6 – 12 months 
Peanut Butter (Opened)“Best By”“Best By” + 3 – 6 months
Homemade Peanut Butter 1 – 3 months

Please note that the dates in the table are approximate. And often the peanut butter will last even longer.

How To Tell If Peanut Butter Is Bad

Since peanut butter contains a lot of fat and a minimal amount of water, bacteria and fungi don’t have much opportunity to live and grow in peanut butter.

Oxygen seems to be the biggest factor that can influence peanut butter (if it hasn’t been contaminated somehow). And as mentioned earlier, it doesn’t make peanut butter go bad, it just alters its taste.

Please bear in mind that when you store peanut butter for a long time, oil might separate and you’ll see it on top of the container’s contents. Exactly the same happens to almond butter. That’s perfectly normal; you can stir the sandwich spread and the peanut butter will be fine again.

Word of caution here – if you notice that peanut butter has a strange (or off) odor, its flavor is altered drastically, or you just see that it’s something wrong with it (besides oil separation), discard it. It’s always better to be safe than sorry.

If the peanut butter tastes just not as good as it used to, that doesn’t mean it’s spoiled. If you can’t find any certain signs of spoilage, chances are it’s safe to consume.

Eating it most likely won’t hurt you, but you might want to discard it due to its quality. It’s up to you. Some people don’t mind peanut butter tasting a little different than usual, some people do.

Peanut Butter FAQ

What about natural peanut butter?

In this article, I don’t mention natural peanut butter, and that’s on purpose.

The term “natural” isn’t clearly defined, so natural peanut butter from each brand has its own unique set of ingredients. Usually, natural PB contains at least 90% peanuts, but besides that, it’s up to each brand what else is there. The healthiest PBs out there are those with one or two ingredients: peanuts and salt.

So, how to store natural peanut butter? The same way you store “normal” peanut butter: in the pantry, tightly closed. There’s no need to refrigerate natural peanut butter unless the producer says so.

Does peanut butter and jelly go bad?

I think it’s safe to say that everyone knows that a peanut butter and jelly sandwich will go bad.

If left out, it will probably take a day or two before it starts to grow mold. If you chuck it into the fridge, it can stay there for quite a long time (think days) without going bad. And by not spoiling I mean it will still be safe to eat.

The issue here is that a PB and jelly sandwich will deteriorate in quality much faster. The bread will become soggy or taste stale, and you will likely prefer to toss it out after a day in the refrigerator.

Of course, you can experiment with different types of bread and amounts of PB and jelly, and maybe you can come up with a combination that lasts a bit longer.