Parmesan cheese, also known as Parmigiano-Reggiano, is a hard Italian cheese with a distinct and robust flavor. It is a staple ingredient in many Italian recipes and is popularly grated over pastas, risottos, and soups. With proper storage, an unopened chunk of Parmesan can last for months past its printed expiration date. However, once opened, Parmesan begins to lose quality and freshness. Read on to learn more about how to maximize the shelf life of Parmesan cheese.
Does Parmesan cheese expire?
Yes, Parmesan cheese does eventually expire and go bad. However, Parmesan is a very hardy cheese and lasts much longer than many other cheese varieties. An unopened wedge of Parmesan has a shelf life of about 10 months from the date it was made. It may last even longer, up to 2 years or more if stored properly. The key factors determining Parmesan’s shelf life are storage temperature, exposure to air, and moisture level.
Printed expiration dates
The printed expiration date on Parmesan refers to an unopened, sealed wedge stored continuously at a proper refrigeration temperature. This date is usually very conservative, and the cheese will likely remain edible for weeks or months beyond that date, given ideal storage conditions. However, once opened, Parmesan will go bad much faster than the printed expiration date due to exposure to air and changes in moisture level.
How to tell if Parmesan cheese has gone bad
There are a few common signs that Parmesan has spoiled and is no longer safe to eat:
- Mold growth – Any fuzzy mold spots, webbing, or dry rot indicates the cheese should be discarded.
- Off odor – Parmesan gives off a distinctively strong, savory aroma when fresh. A sour, ammonia-like, or putrid smell means it’s gone bad.
- Off flavor – Rancid, bitter, or unpleasant flavors are a sign the cheese is spoiled.
- Discoloration – Though Parmesan naturally darkens with age, any unnatural green, gray, or black discoloration indicates spoilage.
- Crumbly texture – Parmesan gets progressively more crumbly with age. However, excessive dryness, cracking, or a gritty, sandy texture is abnormal.
When in doubt, remember the old adage – “When in doubt, throw it out.” Don’t risk getting sick from eating spoiled Parmesan.
Maximizing the shelf life of Parmesan cheese
Here are some tips for making your Parmesan cheese last as long as possible:
Purchase date and size
- Check the printed “made on” date and buy the freshest wedge possible.
- Buy smaller wedges or pieces – the less surface area exposed to air, the better.
Storage method
- Keep refrigerated – Proper cold storage at 35-40°F is ideal. Keep Parmesan in the deli drawer vs. main compartment.
- Wrap tightly – Cover the cut surface thoroughly in plastic wrap or parchment paper to minimize air exposure.
- Use original packaging – Until opening, keep Parmesan in its original paper or wax wrapping.
- Limit humidity – Use a dry container or bag instead of plastic, which can trap moisture.
Usage
- Cut off moldy areas – When Parmesan begins to mold, cut at least 1 inch around any spots.
- Blot oil – Use a paper towel to absorb excess oil that leaches out as it ages.
- Don’t re-wrap after use – Dry it thoroughly and wrap it tightly to limit air exposure.
- Portion into smaller pieces – Break off only what you plan to use within a week or 2.
Refrigerator shelf life of Parmesan cheese
Under proper refrigeration, here are some general guidelines for Parmesan cheese shelf life:
Unopened Parmesan
- Commercial use or deli blocks: About 6 months from the production date
- Wedges with rind: 10 to 12 months
- Pre-grated: 4 to 6 months
Opened Parmesan
- Commercial deli block: About 6 weeks
- Wedge or piece: 2 to 4 weeks
- Pre-grated: 1 to 2 weeks
Note that shelf life depends heavily on storage conditions and how well the cheese is rewrapped. Properly stored Parmesan may last longer than the times above.
Can you freeze Parmesan cheese?
Yes, it’s possible to freeze Parmesan cheese for long-term storage. Freezing stops the aging process and prevents mold growth. Frozen Parmesan will retain good quality and flavor for up to 10 months.
How to freeze Parmesan
Follow these steps for freezing Parmesan properly:
- Wrap wedge tightly in plastic wrap, pressing out all air. Double wrap for extra protection.
- Place in freezer bag or airtight container.
- Freeze for up to 10 months.
- Thaw in the refrigerator overnight before use.
- Use within 1 week after thawing.
Freeze grated Parmesan
Pre-grated Parmesan doesn’t freeze quite as well. For best results:
- Spread grated cheese in a thin layer on a parchment-lined sheet.
- Place in freezer until completely firm.
- Transfer to airtight freezer bag or container.
- Store frozen up to 4 months.
How long does opened Parmesan last in the fridge?
Once opened, Parmesan cheese has a much shorter shelf life. Exposure to air and fluctuations in temperature and humidity accelerate spoilage. Properly stored, opened Parmesan cheese will typically last:
- 2-4 weeks for a wedge with the rind still attached.
- 1-2 weeks for a piece that’s been cut off from the wedge.
- 1 week for grated Parmesan cheese.
Make sure to wrap Parmesan tight and create a barrier from air exposure after each use. Use cheese within that timeframe for best flavor and freshness.
Signs Parmesan has gone bad after opening
Check opened Parmesan periodically for the following signs of spoilage:
- Mold spots or dry, pitted areas
- Excessive oil seeping out
- Unusual odors
- Extreme dryness and crumbling
- Off or bitter flavors
Discard Parmesan at the first signs of spoilage. Don’t risk eating moldy cheese.
Does Parmesan cheese need to be refrigerated?
Yes, for both food safety and to maximize shelf life, Parmesan cheese needs proper refrigeration:
- Unopened wedges – Refrigerate at 35-40°F immediately after purchase.
- Opened Parmesan – Should always be stored in the refrigerator. Wrap tightly.
- Shelf life – Refrigeration extends the shelf life significantly over room temp storage.
- Food safety – The low moisture content makes Parmesan less prone to bacterial growth. However, refrigeration prevents any pathogens from multiplying.
Note that some specialty aged Parmesan may be safe at room temperature because of its very low moisture content and high acidity. However, refrigeration is still best practice to extend quality.
How to store Parmesan cheese
Here are some tips for maximizing Parmesan’s shelf life through proper storage:
Short-term storage
- Keep refrigerated in original deli packaging or wrap wedge tightly in plastic wrap.
- If opened, wrap tightly in layers of plastic wrap pressing out air.
- Place in the fridge deli drawer away from high-moisture items like produce.
- Avoid freezing Parmesan unless you plan to store it long term.
Long-term storage
- Freeze wedges up to 10 months for infrequent use. Double wrap in plastic.
- Store grated Parmesan frozen up to 4 months. Spread in a thin layer on a parchment-lined pan before freezing.
- Thaw overnight in the fridge before use.
- Parmesan tastes best fresh. Freeze only what you can’t use up quickly.
Avoid
- Plastic bags, which can trap moisture and cause mold
- Extreme temperature fluctuations
- Direct light, heat, or humidity
- Stacking wedges, which can damage the rind
- Freezing and thawing repeatedly
What happens if you eat expired Parmesan cheese?
Eating small amounts of expired Parmesan is unlikely to cause illness. However, there are some risks of consuming spoiled Parmesan cheese:
- Foodborne illness – Moldy cheeses may contain harmful bacteria like E. coli, Listeria, or Salmonella.
- Food poisoning – Spoiled cheeses can contain toxins that cause vomiting, diarrhea, and fever.
- Allergic reaction – Mold allergies can trigger rashes, breathing issues, or other reactions.
- Texture/flavor – Expired Parmesan becomes dry, gritty, bitter, and unpalatable.
When Parmesan has gone moldy, developed a rancid or ammonia-like smell, or tastes unpleasant, it’s best to discard it. Don’t eat Parmesan with abnormal colors, textures, or odors.
How to store Parmesan cheese after opening
Once opened, Parmesan cheese is highly perishable and needs proper storage. Here are some tips:
- Immediately rewrap the cheese tightly in plastic wrap, parchment paper, or foil.
- Press out as much air as possible before sealing.
- Use cheese within 2 weeks for wedges, 1 week for pieces, and just a few days for grated.
- If mold appears, cut 1 inch around it before rewrapping.
- Store in the refrigerator, ideally in a deli drawer or cheese compartment.
- Keep Parmesan away from high-moisture foods like produce and condiments.
With proper refrigeration and minimal air exposure, opened Parmesan can retain good eating quality for around 2 to 4 weeks.
Frequently Asked Questions
Does Parmesan cheese need to be kept refrigerated?
Yes, it’s important to refrigerate Parmesan cheese. Proper cold storage extends shelf life and prevents contamination or bacterial growth. Store opened and unopened Parmesan wedges in the fridge at 35-40°F.
How long does Parmesan last unrefrigerated?
At room temperature, Parmesan’s shelf life is cut significantly shorter. Unopened, it may last 2-3 weeks but quickly dries out. Opened Parmesan should never sit unrefrigerated more than 2 hours before harmful bacteria can multiply.
Can you freeze shredded Parmesan?
Yes, it’s possible to freeze grated Parmesan for up to 4 months. Spread shredded cheese in a thin layer on parchment paper and fully freeze before transferring to an airtight container. Thaw in the refrigerator before use.
Does Parmesan cheese mold?
Yes, Parmesan can develop mold growth either on the rind or inside the cheese. This is more common when stored improperly in warmer temperatures or with too much humidity. Discard Parmesan at any sign of mold, fuzziness, or spotting.
Can you eat Parmesan cheese rind?
Yes, the rind on Parmesan cheese is completely edible and safe to eat. The rind is simply the exterior that forms during the aging process. It has a strong, earthy flavor and pleasant crunch. Parmesan rind can be used to add flavor to recipes.
Conclusion
With proper refrigeration and minimal exposure to air and humidity, Parmesan cheese can keep well for extended periods past its printed expiration date. An unopened wedge has a shelf life around 10-12 months, while opened Parmesan lasts roughly 2-4 weeks. Check for signs of mold, off-smells, and unusual textures to determine if your Parmesan cheese has spoiled. Storing Parmesan cheese in an airtight container in the refrigerator deli drawer maximizes its freshness and shelf life.
