How to tell if pistachios are bad? (5+ signs of spoilage)

In this brief article, we will answer the question “How to tell if pistachios are bad?” and methods to store pistachios.

How to tell if pistachios are bad?

Pistachios give off a foul odor when they turn bad. This can especially occur if the pistachios are not stored properly.

The other methods for detecting spoilt pistachios are mentioned below.

  • Mold growth on the pistachios is a definite indicator of spoilage. Mold can be detected as a powdery covering on the outside of the pistachios.
  • If the nuts look dehydrated and there is more skin than the meat of the nut observed, it is another indicator of deterioration.
  • If you observe any pests or insects in the package of the nut, it is better to discard the package.
  • You can detect rancidity in the pistachios by smelling them or tasting them. If the nuts taste bitter it is a sign of spoilage.
  • The nuts can also lose their crunchiness if it has been stale. You can roast the nuts for 15 minutes at 200℉ to bring back the crunchiness.
  • Fresh pistachios would have yellow or green nutmeat. When the pistachios would start getting spoilt, the color would change to a dark brown color. 

How to store pistachios?

  • You can store pistachios at room temperature for a shorter duration. Make sure to keep the pistachios away from heat or light.
  • If you buy pistachios in bulk, you can store them in their original package. You can also keep them in a plastic or paper bag. This would be appropriate for a short-term storage purpose only.
  • If you want to store pistachios long-term, keep them in a resealable bag or you can shift the nuts to a resealable bag immediately after opening it. This will prevent the nuts from taking in strong odors.
  • Keep the pistachios in the fridge or the freezer if you do not plan on consuming them for a long time. Pantry is good for temporary storage.
  • If you are not sure that the pistachios being bought are of good quality, avoid buying them in bulk. Also, buy packaged ones. Unshelled pistachios also last longer.

Is it fine to freeze pistachios?

Yes, it is fine to freeze pistachios. Freezing can prolong the shelf-life of pistachios compared to refrigeration.  For freezing, place the pistachios in a freezer bag or airtight containers. You can thaw the pistachios at room temperature when you feel to consume them.

You can thaw and refreeze roasted pistachios multiple times. If the pistachios appear shrunken after freeing, you can place them in the oven for 15 minutes at 150℉. This will bring back the crispiness in pistachios.

What is the shelf-life of pistachios?

If the pistachios are frozen, they can last for 1-2 years. Packaged pistachios can come with a date though the pistachios are not likely to get spoilt past the date. Please note that the table below is an estimate and not an exact shelf-life of pistachios.

Type of pistachiosPantryRefrigeratorFreezer
Shelled pistachiosApproximately 5 monthsApproximately 1 yearApproximately 2 years
Unshelled pistachiosApproximately 6 monthsApproximately 1 yearApproximately 1 year

Processed pistachios are likely to have a longer shelf-life than raw and unprocessed pistachios. This is because processed pistachios have a reduced fat content and are loaded with preservatives. The unprocessed ones get oxidized easily and become rancid.

Roasted and dry pistachios have a comparatively shorter shelf-life compared to shelled or unshelled pistachios. It cannot last approximately for 5-6 months. 

Other FAQs about pistachios that you may be interested in.

What needs to be kept in mind while buying pistachios?

  • Avoid buying pistachios that have cracked shells as it is likely to be spoilt.
  • Avoid buying pistachios that are colored with a red or green color.
  • Prefer to buy pistachios having green nut meat as green nut meats taste much better.
  • If you are looking to buy shelled pistachios, buy the ones that have an ivory color without any spotting on their shells.

Is it fine to consume pistachios that are closed?

Yes, it is fine to consume them though open pistachios are mature pistachios. If the pistachios are closed, it is an indication that the pistachios are immature. Opening closed pistachio is also not easy. You can try opening the pistachio using a nutcracker.

Is it fine to consume pistachios past their expiry date?

The printed date provided on the pistachio’s packet is an estimate of how long the pistachio remains in good quality. You can smell and taste the pistachios to determine their quality. 

If it isn’t a year past the expiry date, the pistachios are not likely to be spoilt. If the nuts give off a bad odor or taste bitter and rancid, it is better to discard them.


In this brief article, we have answered the question “How to tell if pistachios are bad?” and methods to store pistachios.


Hi, I am Charlotte, I love cooking and in my previous life, I was a chef. I bring some of my experience to the recipes on this hub and answer your food questions.