Do Pistachios Go Bad? Spoilage Signs & Storage Tips

Nothing beats the joy of indulging in crunchy, highly addictive pistachios – unless they are stale or plain bad, that is! To make matters worse- these nuts are not cheap, so I have set out on a mission to find out if pistachios do go bad, signs to look out for, and alternative uses for stale nuts.

Pistachios can go bad, especially if they have a chemical smell, bitter taste, dried appearance, mold, or insects. Unshelled pistachios stored in an airtight container will only go bad after six months in a cool, dry area like a pantry, after one year in a fridge, and 24 months in a freezer.

While pistachios can go bad, and I will share my tell-tail signs, I have discovered that some pistachio types offer far better value for money. So, if you want to know what they are and enjoy their nutty-deliciousness for far longer – read on!

How To Tell If Your Pistachios Are Bad

While pistachios have a relatively long shelf life if stored correctly, they reach a stage where they are sadly better off in your trashcan. So, let’s look at those easy-to-spot tell-tale signs that your pistachios are bad.

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Sign #1:They Smell And Taste Bad

While pistachios don’t become rancid quickly as they are relatively low in polyunsaturated fats, it does happen with time, and the best giveaway is if they smell or taste bad.

A great tell-tale sign is if they have a chemical smell that resembles putty or old paint or tastes incredibly bitter with a sharp, unpleasant aftertaste.

Sign #2: They Look Different

Last, but not least, if your pistachios have shriveled, look smaller, or dried out, they are probably bad and should ideally be tossed away.

Sign #3: You Spot Mold

Although pistachios are not typically prone to mold if stored optimally, it does happen, especially if they are kept in a damp location. So, toss them as soon as you see mold.

Sign #4: Pantry Insects

If you have found insects in your pantry and your pistachios are not stored in an airtight container, then it’s very likely that they have found a new home amidst the nuts. So, inspect the bag thoroughly for any hidden nasty critters.

The Best Way To Store Pistachios

While some University academics believe that pistachios can only remain fresh at room temperature for a few weeks, USDA research studies proved that once pistachios are dried, they can retain their freshness if stored at temperatures of 68 ºF for up to a year.

However, there has also been a lot of debate about whether to store pistachios at room temperature, in the fridge, or freezer. While all these options have merit, it depends on how long you want to store them.

If you have a relatively small quantity of pistachios in a sealed bag that you are planning to snack on shortly, keep it in the original resealable bag or place it in sturdy airtight plastic or glass container in a cool and dark area like your pantry where they should be fine for up to 6 months.

However, if you can’t resist the temptation of buying in bulk, especially if they are sold at bargain-basement prices, store them in your fridge in a sealed container where they can stay fresh for up to a year or up to 24 months in your freezer.

How To Open Semi-Closed Pistachios

If you bought unshelled pistachios, chances are great that you will encounter one of those (sometimes irritating) semi-closed nuts.

However, before we delve into the easiest ways to open them, it’s important to point out that closed pistachios are normally empty as they did not reach maturity, so don’t bother opening them as it’s not worth the hassle.

My favorite tried and tested opening hack is to insert the pointed end of a loosened shell in the nut opening and use it as a leaver until it magically pops open, and in most instances, you don’t need any other tools.

Other easy ways of opening them include inserting a knife’s point in the tiny crack and moving it around until it pops open or using a nutcracker or a garlic press – just be gentle as you can easily crush the entire nut.

Alternatively, if you have many semi-closed pistachios, wrap them in a kitchen towel and gently crack them open with your rolling pin.

Whole Vs. Shelled Pistachios: Which One Is The Best?

Although not having to grab rolling pins or knives to enjoy your favorite snacks is super convenient, unshelled pistachios last far longer than their easy-to-eat counterparts.

Unshelled pistachios last far longer because they are more insulated and less prone to being damaged by environmental factors like humidity.

So, if you want to enjoy your pistachios for longer, and don’t mind the effort of removing their shells (which can also be fun), choose an unshelled product as it offers far better value for money compared with shelled varieties.

What to Make With Stale Pistachios

While you should get rid of bad pistachios that smell chemical or taste bitter, stale pistachios have various uses, and as they say: waste not, want not!

The quickest way to revive stale pistachios is to toast them a little in a dry non-stick skillet or in the oven at 350 degrees for 15-20 minutes on a cookie sheet. However, move them around so that they don’t burn.

You can even create sweet or salty oven-roasted snacks by coating them in a little olive oil and honey or salty snacks enthused with fresh rosemary and sea salt. Your options are endless!

Once they have cooled down enough, for at least an hour, and taste fine, you can use them to make a healthy crunchy salad, turn them into pesto, or even a decadent pistachio ice cream.

Just make sure you eat the roasted pistachio nuts as soon as possible, as they will only remain edible for between 3-5 days even though you have given them a new lease of life.

More Questions About Do Pistachios Go Bad

Can you eat out-of-date or expired pistachios?

If your pistachios have a best-by-date label, remember that it is just a rough guide for how long they will be fresh enough to eat.

A month or two past their expiry date should not make a difference if you inspect them thoroughly for any of the above-mentioned tell-tale signs.

Even if a taste test proves that they are rancid, you don’t have to worry or rush off to the hospital, as pistachios that have gone bad are only unsafe if eaten in large quantities.

Bulk-bought pistachios, without best-by-dates, should also be fine to consume if you can’t find any issues with their quality.

While stale pistachios should be fine as a snack, I would not suggest using them in their current state (or unroasted) for a cake or any baked goods as you will taste that they are not fresh.

How long do shelled pistachios normally last?

Pistachio shells prolong their shelf life as they stop them from oxidizing, so if they are open, store them immediately in an airtight container, and they should stay fresh for approximately three weeks or up to a month at room temperature.

How long does it normally take for pistachios to go bad?

Pistachios can retain their crunchy taste for up to 12 months if stored correctly, and some believe that they can last up to 24 months if frozen in an airtight container.


Pistachios are an awesome nut used in a variety of recipes. However, if you forget about your pistachios in the pantry they can still go bad over time. Make sure to store them the correct way, and always check for shriveling, mold, and insects before eating!

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