Let’s talk about whether peanut butter goes bad or not, how long it lasts, and when you should toss it.
Say you have a peanut butter jar that’s been opened for a couple of months already. Then, one day, you start thinking: how long does peanut butter last? Does peanut butter ever go bad?
Or maybe your PB is already beyond the printed date, and you want to know if eating it is safe.
If either sounds familiar, this article is for you. Read on.
Table of Contents
- Does Peanut Butter Go Bad?
- How to Tell if Peanut Butter Is Bad?
- How Long Does Peanut Butter Last?
- How To Store Peanut Butter
- Does Peanut Butter Need to Be Refrigerated?
- Peanut Butter Spoilage and Shelf Life Summary
Does Peanut Butter Go Bad?
Peanut butter lasts months even if you leave it at room temperature, but it doesn’t last forever. Stored long enough or in warm conditions, the fat from ground peanuts will eventually go rancid, and that’s when you should toss it.
Let’s talk about rancidification then.
How to Tell if Your Peanut Butter Is Rancid?
Rancid PB will taste sharp, bitter, and “off” instead of soft and peanut-like. It may also start to give off a weird odor that might remind you of nail polish remover, but that’s not always easy to notice.
If you’re buying sweetened peanut butter, e.g., Skippy, that flavor alteration probably won’t be as easy to notice because the sugar affects the overall taste.
Rancidification is a process that tastes months. That means you won’t notice any changes if you use your PB regularly. They’re apparent only if you return to an old jar after a couple of weeks or months.
Now, eating rancid nuts is not unsafe, so if you eat a tablespoon of rancid PB, nothing bad should happen immediately. Besides experiencing that unpleasant flavor, of course.
That said, consuming oxidized oils isn’t beneficial long-term, so it’s best to toss that peanut butter.
(In case you’re wondering, peanut butter goes rancid the same way peanuts go rancid.)
Next, let’s talk about separated peanut butter.
Is Separated Peanut Butter Spoiled?
Separated peanut butter, meaning one with a layer of oil on top, is perfectly okay and safe to eat. You only need to stir that oil back in, and you’re good to go.
There are a couple of options you can try to make separated PB nice and spreadable:
- Stir it using a spoon or a fork. That works great if the ground peanuts on the bottom aren’t super dry yet.
- Cut into the dry peanut mass with a knife all the way to the bottom, and make a couple of lines this way. That will allow some of the oil to get to the bottom and incorporate into those ground peanuts. It should make stirring easier after a couple of hours.
- Store the jar upside down. Since peanut oil migrates to the top, it’ll try to get to the bottom when stored this way. Again, you’ll probably need at least a couple of hours, if not days, to get decent results. And remember to seal that lid tightly.
- Use a food processor or blender. If you have a powerful blender or food processor, you can try to use it to stir the oil and dry mass together. Remember to shut the tool down immediately if the blade can’t move.
(The same techniques work when you’re trying to fix separated almond butter.)
Peanut butter spreads that include another oil usually don’t separate and stay nice and spreadable throughout storage time. That’s why PB, without any extra ingredients, separates and some popular brands like Skippy don’t.
Finally, if the whole bottom is super dry and you can’t stir everything together, it’s okay to toss that PB for quality reasons.
Having that covered, let’s talk about the actual spoilage signs of peanut butter.
How to Tell if Peanut Butter Is Bad?
Throw out peanut butter if:
- It’s rancid. If your PB tastes off, sharp, or bitter, it’s time to let it go. The same is true if it gives off a sour or chemical-like aroma.
- It’s completely separated, and you can’t fix it by stirring. Again, separation is normal and reversible for plain peanut butter. But if the nut butter is beyond fixing, you have no choice but to toss it.
- There’s mold. Peanut butter is primarily fat, and that’s why it’s not particularly prone to grow mold (ever seen moldy lard?). But if it’s open and gets contaminated, you may find mold in a PB jar. If that’s the case, toss the spread.
If anything else about the butter seems fishy, err on the side of caution and toss it.
As I mentioned earlier, going rancid takes time, and while your peanut butter might not be rancid already, you may notice that the flavor has changed and you don’t like it anymore.
That doesn’t necessarily mean the sandwich spread is gone, but it’s probably better to toss it if things get to that point.
Knowing that, you probably want to know how long, realistically, peanut butter keeps its quality. Let’s talk about that.
How Long Does Peanut Butter Last?
Peanut butter usually has a shelf life of 9 months up to a year. And if it contains preservatives, that period will be a couple of months longer.
Once you open a fresh jar of peanut butter, it typically retains quality for about 6 months or a couple of weeks beyond the printed date, whichever comes first. You can add a few months to that by storing it in the fridge.
That’s the gist of it. Let’s jump into details.
A peanut butter jar comes with a best-by date printed on the label that’s a year or less from the time the spread was produced and jarred. That date isn’t an expiration date but a rough estimate of how long that peanut butter should last.
In most cases, if you store the nut butter in decent conditions, it’ll keep for at least a couple of weeks (if not months) beyond that date. And even longer if you refrigerate it.
As long as the jar is unopened, rancidification proceeds fairly slowly due to lack of fresh air. That means that if you have two jars of PB with the same date and stored in the same spot, one that you open for the first time today will be fresher than one that’s been opened a couple of months ago.
That said, peanut butter doesn’t last forever if you never open it up. It’ll still go rancid at some point, and if you open a jar that’s a few months beyond the printed date, you may find that it’s rancid already.
After opening, peanut butter stays good for about 6 months or a couple of weeks beyond the date printed on the jar, whichever comes first.
If you open a jar a week before the best-by date, that peanut butter will probably retain quality for a month or two, but it most likely won’t last the whole half a year.
Once you first open your peanut butter jar, fresh air gets to the spread, and the degradation process accelerates a bit.
That’s why some sellers state specifically how long their peanut butter stays good after opening. For example, Peanut Butter & CO says you should finish the jar within six months.
Others, like Skippy, ask you to observe the date on the label without worrying too much about when you opened it.
What’s sure is that the longer the jar stays open, the worst the taste will be. But how quickly that peanut butter will degrade depends on several factors (like ingredients and storage habits) and varies between brands.
After “Expiration” Date
Peanut butter typically keeps quality for between a couple of weeks to a couple of months beyond the printed date.
Unfortunately, it’s impossible to pinpoint exactly how long peanut butter is good for after the “expiration.” That depends on how you store the jar, how long it’s already opened, and whether it contains any preservatives.
For starters, refrigerated peanut butter tends to last longer than one stored on the counter, the same way refrigerated oils don’t go rancid as quickly as those held at room temperature.
Next, as I already pointed out above, the later you open the jar, the longer beyond its printed date the spread will keep.
Last, PB with extra oils, salt, or other ingredients added to make it more stable for a prolonged period will also help it last longer after the “expiration” date.
So if you’re wondering what happens if you eat expired peanut butter, the answer is: in most cases, nothing. As long as the spread is not rancid and doesn’t show any other signs of spoilage, it’s most likely safe to eat.
How To Store Peanut Butter
Store peanut butter in a cool and dark place away from heat sources. A cupboard in the kitchen or in the pantry are both good options. Once you open the jar, you can still store it at room temperature – there’s no need for refrigeration.
Peanut butter is shelf stable, and most sellers recommend storing it at ambient temperature both before and after opening (, , ). This way, it stays nice and spreadable.
That said, refrigeration is optional, and it helps peanut butter retain quality for longer. So if you’re using it only once in a blue moon and need it to keep for as long as possible, keeping it in the fridge might be worth considering.
Another benefit of refrigeration is that it slows down the naturally occurring separation that I talked about in the section on spoilage.
But it does come at a cost – the nut butter doesn’t spread as easily when it’s cold. And you might need to warm it up on the counter for a couple of hours before it becomes spreadable again.
Last but not least, remember about storage basics such as keeping the jar sealed when not in use and always using clean knives, spoons, or whatever you use to get some PB.
Does Peanut Butter Need to Be Refrigerated?
You don’t need to refrigerate peanut butter, but it’s helpful if you want to store the spread for a long time or you’re struggling with oil separation. The main downside of keeping peanut butter in the fridge is that it becomes firmer and more difficult to spread.
In other words, you can store PB in the fridge, but it comes with benefits and costs. And it’s up to you to do the math.
I know some sites suggest you should refrigerate PB after opening, but that’s not what most sellers recommend. And unless you’re dealing with one of the mentioned issues, I don’t think losing that spreadability is worth it.
(Nutella also hardens when refrigerated.)
All in all, refrigerate peanut butter if you need to store it for a long time. Otherwise, keep it at room temperature and enjoy it often.
Peanut Butter Spoilage and Shelf Life Summary
Thanks for reading this primer on peanut butter. Here are the takeaways:
- Peanut butter goes rancid if stored for too long or in bad conditions. You can tell that yours is rancid if it tastes sharp or bitter. Oil separation is not a spoilage sign.
- Peanut butter typically lasts between 9 and 12 months. After opening, the sandwich spread is good for around 6 months or a couple of weeks past the printed date, whichever comes first.
- Store peanut butter in a cold and dark place, sealed tightly. You don’t need to refrigerate it (even after opening), but refrigeration might be helpful if you need to store the spread for a long time without it going rancid.