So you’ve bought a big block of parmesan on a sale to use as a topping for your casseroles. And as the cheese sits in the fridge, after a few weeks, you start wondering: does parmesan cheese go bad?
Or maybe you’ve chosen the more convenient approach and went with shredded or grated parmesan that you can use right away. And now you’re not quite sure how long will the opened parmesan last or if you should refrigerate it or not.
Either way, if you’d like to learn a few things about storage, shelf life, and going bad of parmesan, this article is for you. In it, we cover both chunks of parmesan as well as its grated and shredded variation.
If that’s something you’d like to learn more about, read on.
How To Store Parmesan Cheese
Let’s start with storing a block (or a chunk) of parmesan. It’s not much different than storing any other hard cheese.
When it comes to where to keep it, you should place it in the fridge once you get home, possibly into the vegetable crisper that’s usually fairly humid.
The blocks are usually vacuum-sealed, and there’s no point in opening the package before you need the cheese.
Once you open the package, there are a few options when it comes to storage. Wrapping the package (or only the cheese) in aluminum foil is one. Alternatively, you can wrap the cheese with cheese paper, wax paper, or parchment paper.
Fortunately for us, someone run a test of various storage methods, to tell us what’s the best option. Based on this article from Cook’s Illustrated simply putting the cheese in a freezer bag and sealing it tightly gives great results.
Alternatively, you can use an airtight container ([PR]), but it’s not quite a good because there’s quite more air in it.
Remember to squeeze as much air from the bag as you can before fastening the seal.
When it comes to shredded and grated parmesan, there are a lot of products out there. And not all of them are created equal.
Basically, you can find both refrigerated and unrefrigerated versions of these. So the best place to store an unopened package is to store it the same way it was stored in the supermarket.
Once you open it, no matter which variety we’re talking about, its place is in the fridge and tightly sealed.
Remember always to use clean utensils when scooping the cheese, to prevent any microbial contamination.
Can You Freeze Parmesan?
Parmesan wedges last quite a while in the fridge, so freezing them is rarely necessary. Shredded parm, on the other hand, lasts only a couple of days (more on that later in the article).
Because of that, you might be looking for ways to extend its shelf life. And freezing is definitely the top choice here.
Fortunately, shredded Parmigiano Reggiano (official parmesan’s name) freezes quite well, and you can use it in a variety of dishes.
Want to learn more? Read our guide to freezing parmesan.
How Long Does Parmesan Cheese Last
Parmesan is a hard cheese, and as such a product it lasts quite some time.
Unopened, the parmesan should last about 7 to 9 months. Of course, the label should include a “use-by” or “best if used by” date, or something like that. And since parmesan is a long-lasting cheese, it should still be okay for a few weeks past that date.
Once you open the package, the parmesan should retain best quality for about 1 to 2 months. It will, however, keep freshness for much longer (as it preserves well [RIU]) , possibly 6+ months of opening.
When it comes to shredded or grated parmesan that’s sold refrigerated, it should have a “use-by” date too. Since the product is shredded, its quality degrades faster. Thus it should keep for about a week past that date, and that’s it.
Once you open the package, use the cheese within 3 to 5 days for best quality, and maybe up to 7 days for an okay quality.
Last but not least, there’s also the grated parmesan that comes in unrefrigerated canisters. It usually lasts about a year, or even more. That parmesan always comes with a best-by date, and you can easily assume that it will keep at least a month past that date. The cheese is dehydrated, so it’s not prone to bacteria growth, hence the long shelf life.
Once you open the package, keep the canister in the fridge. It should last at least a couple of months, but check the label to make sure.
|Parmesan (unopened)||7 – 9 months or Use-by + 1 month|
|Parmesan (opened)||1 – 2 months (best quality)|
|Shredded/grated parmesan (sold refrigerated, unopened)||Use-by + 7 days|
|Shredded/grated parmesan (sold refrigerated, opened)||3 – 7 days|
|Grated parmesan (sold unrefrigerated, unopened)||Best-by + 1 month|
|Grated parmesan (sold unrefrigerated, opened)||4 – 6 months|
Please note the periods above are estimates only.
How To Tell If Parmesan Cheese Has Gone Bad
Usually, when cheese goes bad, it is easy to see the mold spots. With hard cheeses like Parmesan, the mold spots can be removed, and you can eat the rest.
Remember that it’s normal that parmesan’s rind is darker and tougher than the rest. It’s still edible, though.
What if the cheese is grated or shredded?
When grated, Parmesan is white to beige in color. If you are wondering if your grated cheese has spoiled, open the container and check the color and smell.
Parmesan going bad will smell funny, and the color will look different. Instead of looking white or beige, the color of the cheese will be more of a yellow or darker beige.
For shredded parmesan, texture change is a good sign of it going bad. If the shredded parmesan feels spongy or wet to the touch, discard it. Same thing if it smells off or “funny.”
For both grated and shredded parmesan, throw the whole package out if there are any signs of mold.