Information on the shelf life of pistachios is all over the place. Some say it’s super short, while others say it’s not that bad. And then there’s this whole thing of whether or not you should refrigerate pistachios.
If you’re not sure what gives, this article should bring you some clarity. In it, I go through everything I think you should know about the storage and shelf life of pistachios. As a bonus, I also cover pistachios going rancid, and what to do with nuts that have lost their crunch.
Let’s dive right in.
How Long Do Pistachios Last?
Let’s start with one thing everyone can agree on: unshelled pistachios last longer than shelled ones. The difference isn’t as pronounced as in walnuts or hazelnuts, though. That’s because pistachios are open-mouth nuts, and the shell doesn’t cover the whole nutmeat.
Now let’s talk about shelf life and what various sources say about it.
For starters, pretty much every reliable source says that cold storage is the solution if you want to keep the pistachios for a long term (USDA, FK, UOC). And by long-term, I mean a year or more.
I don’t know about you, but when I buy pistachios, I get back home with a reasonable amount enough for a couple of weeks. Or a few months tops if there’s a sale. And I don’t have the spare space in the fridge or freezer to keep those nuts in there.
In short, I much prefer storing pistachios at close to room temperature. And that’s where the discrepancies between sources come in.
Food Keeper app (FK) says pistachios last about three weeks at room temp. You can find similar claims all around the Internet. And that seems a bit too low.
Fortunately, you can find the following in the agriculture handbook from the United States Department of Agriculture (USDA) about pistachios:
Once they have been dried, nuts can be held at 20 ºC (68 ºF) and 65 to 70% RH for up to a year (…)
That’s much more like it, and that’s much closer to what you can find on labels of most packaged pistachios. I’m yet to see a pack of pistachios that says “finish in three weeks or refrigerate.”
The longer period makes even more sense if you do a bit more research. As it turns out, pistachios don’t have that much polyunsaturated fatty acids, and because of that, they are less prone to going rancid than some other nuts (e.g., walnuts or pecans) (USDA). That goes well with what Healthline says about polyunsaturated fats and rancidity (HL).
Overall, I’m not entirely convinced that pistachios retain top quality for a year in the pantry, so I’d stick with a safe estimate of 6 to 9 months. And that’s long enough for almost all of us to go through our pistachios.
Now that we’ve established how long they keep quality, let’s talk about storage.
How To Store Pistachios?
Proper storage is what you need to keep the oil in pistachios from going rancid (UOC). To do that, you should keep the nuts away from air, light, and heat.
If you buy pistachios in bulk, the plastic or paper bag you get is good enough for a couple of weeks. If you want to keep the nuts in tip-top shape, transfer them to a resealable airtight container, either plastic or glass.
For pre-packaged pistachios, most of these come in resealable bags, so that’s done for you already.
The container takes care of keeping the nuts away from fresh air, so now you only need to find a place where it’s not in sunlight and nowhere near any heat sources. A cabinet in the kitchen or pantry is usually enough for that.
Of course, if you decide to refrigerate or freeze pistachios, all you need to worry about is the container. The fridge or freezer will take care of the rest.
How to Tell If Pistachios Have Gone Bad?
Even though pistachios last quite some time, they definitely can go bad, especially if you don’t take good care of them.
If they are moldy or dried out, toss them out.
If they look healthy, you need to check if they are rancid. If the pistachios smell like paint or taste harsh and bitter, that’s a sure sign of rancidity. Rancid pistachios won’t make you sick but aren’t particularly healthy (HL). The taste is no good either, so it’s best to throw them out.
Given that everything with pistachios seems to be okay, consider the taste and texture. If they could use a bit more crunch or taste somewhat stale, consider roasting them.
While roasting helps revive old nuts, it can also damage the cells and lead to the formation of harmful free radicals (HL). Because of that, you shouldn’t go about this willy-nilly. Here’s what Healthline recommends:
- roast in a preheated oven
- go with low 248–284°F (120–140°C) to middle temperatures 284–320°F (140–160°C)
- keep the time short, up to 15 minutes to keep vitamin loss to a minimum
A perfect (food safety-wise) roast would be at about 284°F (140°C) for approximately 15 minutes. It should make the texture crunchier, the color darken a bit, and the nuts more fragrant. All thanks to the chemical reaction called the Maillard reaction (HL).
Questions about Pistachios
Why are pistachios sold in their shells?
First of all, shelling mature pistachios is both easy and satisfying. Many people love the act and even use it as a social activity. Plus having to remove the shell before eating eat one means you won’t eat as much.
The second reason is economical. Shelled pistachios are twice as expensive as unshelled ones, so they aren’t nearly as popular.
Sources
- USDA United States Department of Agriculture: The Commercial Storage of Fruits, Vegetables, and Florist and Nursery Stocks
- FK FoodKeeper App
- HL Healthline: Raw vs Roasted Nuts: Which is Healthier?
- ND Nutrition Data: Pistachios
- UOC University of California – Nuts: Safe Methods for Consumers to Handle, Store, and Enjoy