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Suppose I know that I'm going to eventually end up grating all of my cheese. Is there a reason to not just toss it all into a blender and store it for later? To be more concrete, I'm particularly interested in the answer as it pertains to Parmigiano-Reggiano and Pecorino Romano, both the bonafide sorts and any variations that can be sold under the same name in the United States.

  • Try it; you'll find that it tends to stick back together and become less appetizing. The bagged pre-grated cheeses you buy tend to be coated in something powdery to prevent sticking, and packaged in a nitrogen atmosphere (which is gone when you open the bag), but they don't really compare to freshly grated IMHO – Caius Jard Nov 25 '20 at 10:57

4 Answers4

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You should only grate cheese as needed, particularly the cheeses you mention. When you grate cheese you create more surface area. That is more surface exposed to air and oxidation, which will degrade the flavor and aroma of the cheese. It is also more prone to drying out further degrading the quality. The cheeses you mention are best when grated for immediate use, but stored in chunks, wrapped and refrigerated.

moscafj
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    @Hobbamok: In an airtight, sealed container oxidation and drying out should be much less of an issue. I’m quite okay with pre-powdered parmesan (I use it when camping). – Michael Nov 23 '20 at 10:26
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    Noteworthy that this is just one example of a general rule. Unless you want to soak or ferment something (e.g. sauerkraut) you *never* shred *anything* ahead of time, for the reasons you mention, plus the evaporation of volatiles which contribute to the aroma (very notable with coffee, even if you vacuum-seal pre-ground coffee). – Peter - Reinstate Monica Nov 23 '20 at 14:04
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    @Michael if you are getting $6 a pound cheese, sure do whatever. But if it's anything decent absolutely don't shred for later use, because you are just wasting money. Airtight containers won't save you unless you are purging the oxygen in there first, which is assumedly something the vast majority of people can't do. – eps Nov 23 '20 at 18:32
  • @eps: I was more thinking about the powdered parmesan you can get at the store. I assume it’s vacuumed or filled with an inert gas. – Michael Nov 23 '20 at 18:52
  • Entropy with regards to cheese. – PCARR Nov 23 '20 at 19:03
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    @eps just out of curiosity, have you seen some kind of chemistry explanation behind exactly much air it takes to ruin some mass of cheese? It would be kind of interesting to see that. – jrh Nov 24 '20 at 04:53
  • Have a one-way gas valve on the container, and throw some nitrogen canisters into it! – Deleted Nov 24 '20 at 18:43
  • I can't comment on cheese specifically, but it's very common to pack factory-processed supermarket foods with gas. Google 'modified atmosphere packaging'. – John Smith Nov 24 '20 at 21:38
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While you don't want to grate the cheese and store it in the fridge, as moscafj's answer says, there is a way you can grate all the parmesan, store it, and use it as needed - just keep it in the freezer.

You can add it directly to whatever you're cooking, no need to defrost, although I don't know how well it would work scattered on top of a finished dish. Make sure to store it in an airtight container (a resealable freezer bag works well).

There's some discussion of this on canyoufreeze.com, including an explanation for why freezing works so well with parmesan:

Parmesan cheese has a low moisture content, making it ideal for freezing. It doesn’t have a tendency to clump together, and is not very susceptible to freezer burn. Grated Parmesan cheese should stay soft even while frozen. It can be used directly out of the freezer, without any need to thaw ahead of time. It’s the ideal cheese for freezing!

BauerPower
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    I can attest that this does indeed work if you are using it directly in a recipe, but you need to be careful that it doesn’t have too much impact on the temperature of whatever you’re adding it to. – Austin Hemmelgarn Nov 23 '20 at 12:40
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    I do this with hard cheeses (Pecorino, Grana Padano) when they start going moldy. I cut out one inch around the moldy bits, grate the rest and freeze it. If it's finely grated it takes very little time to defrost if you spread it out on a plate or something. – JBGreen Nov 23 '20 at 16:17
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Short answer: Grated cheese goes moldy quickly.

Long answer: We regularly grate cheese and pack them in vacuum bags in larger quantities. They usually go moldy within a week or two, even in the fridge. Frozen storage should be possible for months, if not years. (I kept grated cheese in the freezer for up to five years.)

From a more general point of view, cheese is already "milk made storable". The rind is a very sophisticated protection against decay. In most cases, it is best to keep the rind as long as possible.

(I am a cheesemaker.)

ManuelAtWork
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    Then how come I can buy grated cheese in bags and that keeps in the fridge for weeks? – Robert Nov 24 '20 at 17:42
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    @Robert Store bought grated cheese has preservatives that help it last longer. – Destin Coleman Nov 24 '20 at 20:39
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    @DestinColeman - neither the Grana Padano nor the Parmigiano I buy in grated packs here in Austria has any additives listed vs. the whole pieces. Not to say that maybe some stuff doesn't need to be listed? But I suspect it's just that it's [packed with some gas](https://en.wikipedia.org/wiki/Packaging_gas) that inhibits spoiling. – Martin Nov 25 '20 at 20:51
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No, you can probably even buy freshly grated cheese from your local cheesemonger.

Max
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    The link I posted in my answer to my own question says that you're wrong. –  Nov 23 '20 at 00:23
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    @PiKindOfGuy What link? You don't have an answer. The link on [this answer](https://cooking.stackexchange.com/a/112790/33098) suggests that it isn't wrong. – JBentley Nov 24 '20 at 11:05
  • @JBentley A moderator deleted my answer since it was a link-only answer. –  Nov 29 '20 at 22:47