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How long does parmesan cheese last? Can it go bad?

Parmesan is basically a wonder food. You can elevate any pasta dish with a bit of fresh grated parm, it basically makes or breaks most risottos, and if you’re trying to be healthy you can bring green veg to life with parmesan. In fact, I used to look after the kids in an Italian family who just ate parmesan chunks straight off the block as snacks. Even the one-year-old did it. 


That might not be for everyone, but it is undeniably moreish!


Parmesan is an absolute staple of the cheese bargain bin. I know I always have at least one wedge in my fridge, sometimes I accidentally buy multiple. 


Hard cheese isn’t exactly cheap, even on offer. And it comes in those big, hard blocks and often a nonresealable package. So I’ve spent some time researching how to store it for freshness, how long it lasts, and what to do with parmesan that is about to go bad.


I’ll answer all those questions and more in this article!


But firstly, let’s look at what sort of cheese parm is…


What is Parmesan?


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Okay, maybe that sounds like a silly question. We all know parm, the king of cheeses!


But in order to think about how long you can store parmesan, it’s a good idea to think about how it’s made.


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Parmesan is a hard, dry Italian cheese made from cows milk. It’s aged for 12-36 months before it gets to the store and then to you. 


A low moisture content means that parmesan isn’t very vulnerable to microbes or mold. It won’t go bad easily if stored correctly.


All Parmesan comes from specific regions of Italy. Other cheeses labeled Imitation Parmesan, and also Grana Padano or simply some variation on ‘Hard Cheese’ should be stored like parmesan and will last about as long as parmesan.


Does Parmesan go Bad?


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It lasts a long time, but of course Parmesan goes bad eventually. 


An unopened wedge of parmesan will last about a year, which is impressive. But how often do you have an unopened pack of cheese lying around?


Once opened, your parmesan should last 6 weeks if you store it properly. 


Is Pregrated Parmesan Different?


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Handmade Pictures/


Pregrated parmesan should last 1 or 2 months once opened, but do look for a best before date as a guide too. Use your initiative with the best before — if your parmesan still seems totally fine a little after that date it probably is. 


The trick to keeping grated parmesan fresh is making sure it stays dry, sealing it after every use, and using clean utensils if you scoop any out. If little bits of other foods get into the package they’re likely to go bad and ruin the cheese.


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How Long Does Hard Cheese Last? Can It Go Bad?

How to Store Parmesan

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Parmesan keeps best when stored at 4-8 °C (39-45 °F), AKA pretty much exactly refrigerator temperature.


You will probably be tempted to stick your open parmesan in a tupperware container, but this actually isn’t the best option. Parmesan cheese lasts longest when you recreate the conditions it’s aged in.


Without a little humidity, parmesan and other hard cheeses dry out. If its environment is too dry, your parmesan will harden and maybe crack, almost like it has developed a skin.


The best way to store a parmesan wedge once opened is in waxed cheese paper or parchment paper. Wrap the wedge and gently tape the paper closed. A reusable food wrap (the kind that’s supposed to replace saran wrap and be better for the environment) will also work well.


Plastic wrap and plastic sandwich bags are not good for storing parmesan and other hard cheeses because they aren’t breathable. The cheese can also stick to them. 


One issue with the breathable paper wrappings is that they can allow parmesan to absorb the odors of other things in your fridge. To avoid this, keep your parmesan in a separate compartment of your fridge and be sure to keep your fridge clean. You can also place the wrapped parmesan in a tupperware container, as long as you open the container up now and again to let the cheese breathe.


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That being said, you’ve got to make sure the container is clean and dry when you put the parmesan in.


Properly storing parmesan will keep it fresh for as long as possible.


Can You Freeze Parmesan?


As parmesan comes in pretty large wedges, you might be wondering if you can freeze your cheese.


If you want to save your leftovers for as long as possible, you can indeed freeze parmesan. 


The freezing and defrosting process can change the texture and lessen the flavor of hard cheeses. It’s best to grate your parmesan before you freeze it. This helps it freeze and defrost evenly and allows you to take a small portion out of the freezer at a time. Freeze parmesan in an airtight container.


Kept in the freezer, parmesan is best eaten within 12-18 months. It won’t go bad after that, but it may lose a lot of its flavor and become very crumbly.


Why Does Parmesan go Bad?

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Elvira Tursynbayeva/

Parmesan goes bad if it is left somewhere too hot, if it is kept in a wet environment or simply after enough time. It will go moldy more quickly in a wet environment, and also tends to take on the scents of other foods stored around it so may become funky if it lives in a messy fridge. 


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Mold often grows on cheeses, although it takes longer on hard cheeses. Because of its low moisture content, parmesan molds are slow-growing.


Parmesan will become rancid and bitter flavored if it has been incorrectly stored, or else it will harden until it simply can’t be cut into!


How to Tell if Parmesan is Bad


As with many foods, the first sign that parmesan is bad often comes in the form of spots of mold. When parmesan is bad, the mold that grows on it is usually green or gray. 


Don’t worry about rough, white spots. These are cheese crystals, and their development on hard cheeses is totally normal.


Because parmesan is hard and lacking in moisture, mold doesn’t spread through it quickly. In fact, if there are only small spots of mold you can still eat this long-lasting cheese. Simply slice off the mold and a couple of centimeters of the parmesan around it. Make sure the knife doesn’t touch the mold. 


If you find mold in grated or shredded parmesan, though, I’m afraid it has to go. It will probably have spread throughout the package. 


Even if there is no mold, your parmesan might still be bad. Just like any cheese, when parmesan is on the turn its taste and smell changes. It may become rancid and acidic, both in smell and flavor. If in doubt, you can taste a little to check. It might not taste very nice, but it won’t hurt you!


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As parmesan lasts a long time, working out if it has gone off can be tough.


Your cheese might also change color as it ages. If it has gone dark and brown or oddly bright yellow you probably shouldn’t eat it. A little discoloration, however, is okay. The outer areas of parmesan sometimes get a bit harder and darker over time, especially if your cheese isn’t stored totally right. 


Remember, parmesan is at its best 4-6 weeks after being opened as long as it’s stored correctly, but it is edible for longer than that. If your cheese loses flavor and its texture changes it is probably still a-okay to consume. If it’s very visibly moldy, a horrible color, or tastes or smells bad, then chuck it!


Can You Use All of Parmesan?

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Robyn Mackenzie/


A lot of people wonder what to do with the harder edges of a chunk of parmesan that is just a little dried out. Plus, there’s the rind to use.


Both rinds and hardened edges of parmesan can be added to soups, stews and sauces to add a rich and salty back note. You can also use them to make a parmesan oil.


Dried out hard cheese (not the rind) or cheese that has been frozen for a long time and has lost a bit of its pizzazz is best melted down into a sauce. 


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How Long Do Limes Last? Can They Go Bad?

Parmesan really is a great ingredient, and it lasts for ages if you store it right. So it makes sense to use every bit of it, right?

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