It’s the end of the month – time to reorganize and restock your pantry. So you stretch your hand to reach that huge pack of cereal at the far corner of the cabinet, but as soon as you move it, a bag of pistachios shows up! It seems like it’s been hiding there for a while, and the first question that comes to your mind is…
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Do Pistachios Go Bad?
Yes, they do. Because of the high content of fat and oil in them, without proper storage, pistachios will become stale or rancid over time.
However, pistachios will tend to deteriorate faster in some conditions than in others. Relative humidity, higher temperatures, and many other factors will all accelerate the spoilage of these delicate nuts. Higher temperatures, for example, will speed up biochemical reactions and encourage the spread of harmful bacteria.
The type of pistachios will also play a huge part in determining how long the nuts will last. Roasted pistachios, for instance, will have a longer shelf life than their raw counterparts. The same is true for unshelled pistachios and those that have been cut into small pieces. They will tend to last longer than shelled and whole pistachios respectively.
How Long Do Pistachios Last?
While there are lots of conflicting information online on how long pistachios last, many retailers give the ‘best before’ date of up to six months. They say that with proper storage, the nuts can last even longer at room temperature.
Of course, if you want to completely extend the life of your pistachios, you should consider storing them in a cooler place. Pistachios placed in cold storage like the refrigerator can retain their quality for up to a year while those in the freezer can go up to two years. If you want your pistachios to last even longer, consider buying the shelled variety.
Also, when you buy your pistachios, always make sure to check the date on the label to know how much time you’ve got before the product goes bad. Usually, you can consume the nuts a few days after the marked date. Just make sure they aren’t stale or moldy.
The following table demonstrates the lifespan of pistachios in a more simplified manner.
| Pistachios variety | Pantry | Refrigerator | Freezer |
| Shelled | 5 months | 1 year | 18 months |
| Unshelled | 6 months | 1 year | 2 years |
4 Tips to Tell If Pistachios Have Gone Bad
Pistachios will go bad quickly if you help them. Meaning, how long it takes before the nuts lose their potency or go bad depends on what you do on your part. If you store your pistachios properly, then you won’t have to worry about them spoiling before the date on the label. If you don’t, then over time, your nuts will exhibit the following signs.
1. Bugs and Insects
If you open a bag of pistachios and forget to seal it properly before storage, bugs will certainly find their way in. You will start seeing tiny holes on the pistachios or dark or brown insects running over the surfaces of the nuts, and that’s a sign that you should toss the bag out.
2. Mold
Mold usually grows in places where there is moisture. When you leave a packet of pistachios open, you not only invite pests; you also increase the risk of molding.
The nuts will absorb moisture from the atmosphere, creating the perfect breeding ground for mold. When this happens, you will see white, dark, or green spots or a powdery coat over your pistachios. Get rid of them right away.
3. Discoloration
The nutmeat inside pistachios should be green or yellow. If it has turned dark brown or another unusual color, it’s probably time to let go of your pistachios.
4. Foul Smell
It’s not always possible to tell if your pistachios have gone bad just by looking at them. Sometimes you have to take a sniff. If you open a packet and there is a strong paint smell, the nuts are probably rancid. Such pistachios will also have a sour taste.
While consuming them may not make you sick right away, the taste and smell can be rather off-putting, so it’s best to just throw them away.
5 Tips to Store Pistachios
Pistachios are expensive. That said, the last thing you want is a pack going bad in the pantry. If you have a bag of pistachios, whether opened or new, it’s important that you follow the manufacturer’s guidelines for storage to help keep the nuts fresh and tasty. For the most part, doing the following will help you ensure proper storage for your stash.
1. Putting Pistachios in an Airtight Container
This is perhaps the best and most effective way to store pistachios. An airtight container will prevent the nuts from soaking up moisture from the air and going stale.
If possible, use a glass container rather than plastic. Glass is less porous than plastic, which means a plastic container will let more air in than a glass one, no matter how tight the lid is. You can go a step further and place the nuts in the refrigerator, as discussed in the next point.
Here is a short video that best demonstrates how to store pistachios in an airtight container:
2. Refrigerate
Nuts generally stay in better condition at lower temperatures, and your bag of pistachios is no different. The reduced temperature slows the rancidification process, keeping the nuts fresh for a longer period. Some manufacturers will even clearly state that their product be kept in the fridge. To extend your pistachios’ life even further, store them in the freezer.
3. Store Away From Strong-Scented Foods
Pistachios, like all nuts, are notorious for absorbing smells from nearby foods. If you want yours to still taste like pistachios rather than fish or garlic months later, place them away from foods with strong odors.
4. Use Resealable Bags
If you don’t have a glass container and you plan on eating your pistachios after a couple days, you can store your nuts in a re-sealable bag. If the bag your pistachios originally came in cannot be resealed, consider transferring them in a sealable Ziplock bag. Your nuts will remain fresh here until the next snacking.
5. Seal With Tape or Rubber Band
This is for true pistachios junkies. If you are one of them, then obviously storing pistachios means being away from the nuts for only a few hours. Reseal the bag with tape or get a rubber band and wrap it around the pack. It should be able to keep your nuts tasting and smelling as good as new.
The Risk of Consuming Expired Pistachios
When you leave pistachios at room temperature for too long, the fats in them start to gradually break down into sour and rancid fatty acids. The process can take years to complete, and the high the volume of the fats broken down, the staler the nuts will get, and the sicker you can become from consuming them.
While eating a few pistachios that have gone bad will probably not make you ill instantly, consuming these regularly can cause problems in your digestive system or lead to more long-term severe effects.
People with a delicate stomach lining, especially, should avoid eating stale pistachios, as these can irritate their digestive tract. Not just that. The broken-down fats can give one gas, make them nauseous, or even give them diarrhea.
Can You Freeze Pistachios?
Yes, you can freeze your pistachios if you want them to last longer than five to six months. Freezing would also be a great option if you live in warm and humid regions. It will keep the product fresh for up to two years.
However, even if you are storing the nuts in the freezer, it is important to lock them in an airtight container. This will keep them not only from getting moist but also from picking up odors from other food items in the freezer.
Basically, the procedure for freezing pistachios is pretty straightforward. First, you need to look for an airtight container or Ziplock bag.
Most of the packaging that pistachios come in is not suitable for freezing this product. The majority of bags cannot be sealed back after they have been opened and that’s why something that locks air out is needed. If you will be using Ziplock, make sure to squeeze out as much air as possible.
Once you have the nuts packed, place them in a suitable spot in the freezer. “Suitable” here means away from foods with strong scents and certainly away from the door where temperatures keep fluctuating.
Summary
Pistachios can last up to two years without going bad. However, as with many food items, their lifespan is dependent on their storage. A pack stored at room temperature will certainly have a shorter lifespan than one that’s refrigerated or frozen. But no matter where they are stored, pistachios must be properly sealed to retain their quality.