Do Pistachios Go Bad? – Full Analysis

Do Pistachios Go Bad? – Full Analysis

Do pistachios go bad? Yes, pistachios can go bad. They contain unsaturated fats so that is what can go bad because once you open the package, the lipids get exposed to the heat. This will cause them to oxidize and become bad, or rancid.

The shelf life of pistachios also depends on whether they are unshelled or shelled or roasted.

How to Tell if Pistachios are Bad?

One way that you can tell if pistachios are bad is to smell them. They will give off a foul odor; some say it smells like nail polish remover, unused plastic containers, or paint. You should also look closely at the pistachios to see if there is any mold on them.

When there is mold, there will be some type of powdery coating them, which can be white, dark colored, or green. If the body of the pistachio nut looks dehydrated and there is only excess skin left, then it is probably bad.

There may also be the presence of bugs in the package that looks brown, green, or black and are running over the surface of the spoiled pistachios. The pistachios may have an odd color and they could be going bad. If the pistachios are bad, throw them away and do not try to use or eat them.

How Long Do Pistachios Last? Shelf Life [Chart]

Type of Pistachio Pantry Refrigerator Freezer
Shelled 6 months 12 months 12 months
Unshelled 5 months 12 months 12 months
Roasted, shelled, or unshelled 3 months 6 months 12 months

Buying Fresh Unshelled Pistachios to Maximize Shelf Life

When buying unshelled pistachios, make sure that you buy good ones because if they are stale and old, they will not last no matter how you store them.

  • Look at the color of the shell to make sure that it is an even ivory cold without any blemishes on the shell.
  • Make sure that they are partially opened because if they are not, they are not mature. You want a small opening but not fully cracked open.
  • Check the nut inside, which you can see from the crack in the shell, to make sure that they are green as these are the ones that taste the best. They can also be pale yellow. They change from bright green to pale yellow to green as they ripen.
  • Check the date if you are buying in bulk. If there is no date but you cannot see the product and check it out, then don’t waste your money. Buy them instead in smaller bags with the expiration date printed on the bag.

If it is possible, before buying a large amount, crack open one or two to see the nut closer inside. Make sure that when you buy in bulk, buy from a store that has a large turnover because if not, those pistachios could have been sitting on the shelf for months.

How to Store Pistachios

To ensure that shelled pistachios stay good and have a long shelf-life make sure that they are stored in a dry cool area. After opening them, store them in an airtight, sealed container. If you are going to freeze them, you should do it immediately and not wait for a few days.

For roasted pistachios, in the shell or shelled, it is best if you buy them in small quantities and then store them in a heavy plastic bag or an airtight container.

The roasted in the shell pistachios have a longer shelf life. If you buy them already roasted, check the package to see if they have a sell-by-date to give you a rough estimate of how long they can last. For the roasted ones, it is best if you use an airtight glass container instead of a plastic container to increase the time for them to remain fresh.

Pistachios, and nuts in general, seem to be a food that is very smell absorbent so keep them away from other strong-smelling foods, whether it is the refrigerator or the panty. To prevent condensation when storing pistachios, make sure that the container or package is airtight, especially in the refrigerator.

If you are roasting pistachios at home, make sure they are completely cool before putting them in the refrigerator or freeze them.

Soft Pistachios – What does it mean?

If you have soft pistachios, it is probably because they have been exposed to the air, absorbing some moisture from it. 

To refresh them up, toast them in the oven by spreading them out on a baking sheet and put the pan in the hot oven. Make sure that after you close the door that you turn the oven off and let them refresh. It should take about five minutes but if they have not dried or turned a little brown you can leave them for about another three minutes in the oven.

Because they can easily burn, keep a close eye on them. If they still feel a bit rubbery after you take them out of the oven after the extra three minutes, let them cool completely. Once they have cooled, they should crisp up and be crunchy again. You can do this to shelled or unshelled pistachios.

What are Pistachios?

Although they are considered nuts, they are botanically seeds of the pistachio tree and grow in bunches like grapes. Pistachios are normally green with a slightly sweet taste but the kernels can vary in colors from yellow to shades of green. 

When pistachios start to grow, they are surrounded by a fleshy exterior so when they ripen, the nut grows inside the shell.

They are about half an inch in diameter and an inch long. If you want to taste a pistachio nut, you will have to crack the hard shell. You can get them roasted, shelled or unshelled, or salted. They belong to the cashew nut family.


  • When storing roasted pistachios, the key to storing them is to make sure that they are not exposed to heat because the heat affects the oils. This is a great reason they go bad quicker.
  • If you eat some stall or bad pistachios you won’t suffer any side effects but may leave an unpleasant taste in your mouth.
  • In addition to the unpleasant smell and taste, they develop an odd brown cover.
  • Shelled pistachios have a longer shelf life than the ones that are unshelled.
  • If you store them in the freezer, they can get freezer burn if they are not packaged in a zip-lock bag with all the air squeezed out or an airtight container.
  • No matter how you store them, pistachios will lose their crunch over time.
  • The lower the temperature, the slower they will go bad. The reason is that high temperatures will allow biochemical reactions to happen faster and help bacteria to thrive.
  • Ones that are processed do have less fat than raw ones and sealed in an airtight bag will be able to last much longer because they oxidize slower.
  • If there is an expiration date, if you open the package before it expires and store it correctly, you can safely eat them within a week after that date. If they have never been opened and stored in the freezer, they can still be used one year after that date.
  • It is recommended that you shell your pistachios and seal them in airtight containers and store them correctly to keep them fresh longer.