You just bought a wedge of Parmesan cheese and you’re not sure if it’s going in the fridge with the Kraft can or in the pantry. Or you’re at a party with Parmesan on the cheese board and you’re wondering how long it can stay calm. Does parmesan cheese need to be refrigerated?
Short answer: Block and pre-grated chilled parmesan cheese should always be chilled. Green shelf cans do not need to be refrigerated before opening, but refrigerating after opening significantly extends their best quality and is recommended by most labels. Parmesan is one of the most stable cheeses you can buy, but that doesn’t mean it doesn’t need refrigeration.
To see how dairy and perishable foods compare in shelf life, visit our The Complete Guide to Food Storage.
To take the keys
- Parmesan block: always in the fridge Opening takes 4 to 6 weeks. Wrap in parchment, not plastic.
- Pre-Grated Chilled Parmesan: always in the fridge Within 3 to 5 days after opening; 7 days at most.
- Green can (shelf stable): before opening the pantry. Refrigerate after opening for best quality; Open between 10 and 12 months.
- Parmesan can be served for 2 hours cheese on a board Hard cheese withstands room temperature better than soft milk.
- Never store in the refrigerator door. Fluctuations in temperature accelerate spoilage even in hard cheeses.
- Parmesan freezes really well. Shredded from a block goes directly from the freezer to the pan without defrosting.
Three product refrigeration guide
Refrigeration rules for Parmesan depend entirely on the product you have. Getting the right regulation for the right product avoids unnecessary waste and food safety errors.
| The type | Before opening | After opening | Duration open |
|---|---|---|---|
| Block or wedge parmesan | Always refrigerate | Cool down; wrap in parchment | 4 to 6 weeks |
| Pre-shredded in the fridge (bag or container) | Always refrigerate | Cool down; close well | 3 to 5 days best quality; 7 days at most |
| The green can on the shelf | Good pantry | Refrigeration is recommended | 10 to 12 months in the refrigerator |
based on USDA FoodKeeper guidelines and manufacturers’ recommendations for hard cheeses. Green cans Shelf life of StillTasty. Always check for signs of deterioration before use.
Why block parmesans that tolerate room temperature better than most cheeses?
The science behind Parmesan’s stability
Parmesan cheese (Parmigiano-Reggiano and similar aged varieties) has a very low moisture content, usually below 30% water, combined with a high concentration of salt. Both factors create an unfavorable environment for the bacteria that most cause milk spoilage. This is why a wedge of Parmesan can sit on a cheese board for 2 hours at a dinner party without becoming dangerous, and why cheese was historically stored and transported at room temperature before modern refrigeration.
However, low moisture content does not mean spoilage proof. Mold spores are ubiquitous in the air and can colonize the surface of Parmesan cheese given enough time at room temperature. Oxidation gradually dulls the flavor. And in a hot kitchen, degradation that would take weeks in the refrigerator takes place in days. Refrigeration is not safe in the short term for block parmesan. It’s the preservation of complex crystalline flavor that you’ve paid for.
The FDA The 2 hour room temperature rule applies to all dairy products including hard cheese. It gives you the perfect amount of time to serve on a cheese board for a dinner party or gathering. After 2 hours, return the cheese to the refrigerator.
The Green Can: A pantry staple with its own rules
The green shelf-stable can (Kraft Shredded Parmesan, Borden and similar brands) is a very different product from fresh Parmesan. It’s dehydrated, highly processed, contains anti-caking agents and preservatives, and has almost no moisture. Unopened, it is actually stable at room temperature for up to a year.
After opening, most labels recommend refrigeration for best quality. The dehydrated nature of the product means it won’t spoil quickly even at room temperature, but refrigeration keeps the flavor longer and prevents the product from absorbing ambient moisture.
Whether an opened green can should be refrigerated is primarily a matter of quality, not safety. The product’s very low moisture content and preservative content mean it can be stored at room temperature without posing a food safety risk. Refrigeration maintains the flavor better within the 10 to 12 month open window.
Parmesan cheese on a board: how long can it stay out?
Block Parmesan is one of the most forgiving cheeses on the cheese board when it comes to room temperature tolerance. Here’s how to handle it properly.
Serve inside at normal room temperature: Take the Parmesan out of the fridge 20 to 30 minutes before serving to allow it to come to temperature. Parmesan’s flavor expands tremendously at room temperature rather than straight from the refrigerator. Return to refrigerator after 2 hours. Rewrap in fresh parchment paper instead of returning to the original wrapper.
Outdoor entertaining above 90°F: The FDA guideline is shortened to 1 hour. Refrigerate parmesan cheese until ready to serve. Its lower moisture content makes it more tolerable than soft cheeses, but the 1-hour limit is still at high heat.
Pre-grated or freshly grated Parmesan to finish the dishes: The small amount used to finish pasta or pizza spends so little time at room temperature that food safety is not a concern. The container goes into the refrigerator immediately after use.
How to properly store parmesan cheese
Good storage practices
Wrap the Parmesan block in parchment paper first. Never place plastic wrap directly against the surface. Plastic traps moisture and promotes mold on the skin. The parchment allows the cheese to breathe. Wrap in parchment, then in a loose-fitting, zip-top bag.
Store cheese in a drawer or at the back of a main shelf. Persistent cold and mild humidity are ideal. The door is the worst place for any cheese.
Keep the green can tightly closed between uses. Moisture is the enemy of dehydrated Parmesan in shelf-stable cans. Put the cover firmly after use in the refrigerator or not.
See also
Don’t grind more than you need at one time. Freshly grated parmesan from a block is used within 1 to 2 weeks. Crushed to order preserves the shelf life of the block and tastes significantly better fresh.
Freeze the excess before turning it off. Shred and freeze Parmesan before the 6-week open window closes. Frozen grated parmesan goes straight from the freezer to the pan without defrosting.
Save the skin. Wrap the Parmesan rind and store it in a sealed bag in the freezer. Add to soups, stews and risottos for a deep savory richness that transforms long-cooked dishes.
Always use clean, dry tools. Wet utensils introduce moisture into both the block and the can, promoting mold and mildew, respectively.
Recipes that use Parmesan cheese
Frequently Asked Questions
Does green kraft need to be refrigerated after opening?
Most labels recommend refrigerating after opening for best quality, and it’s good practice. The product is stable before opening due to very low moisture and preservatives, but after opening it maintains the sharpest flavor in the refrigerator for a long shelf life of 10 to 12 months. Some people keep the can in the pantry after opening it without any problems; the product is too dry to be a significant food safety concern. If you use it within a few months, storage is fine. If you plan to keep it for about a year after opening, the refrigerator is the best option.
I left a parmesan wedge on the counter overnight. Is it safe yet?
As for block parmesan, overnight is more forgiving than overnight with smooth milk, but still exceeds the FDA’s safe 2-hour guideline. Look closely at the cheese: look for new molds, smell any sour or sour notes, and check the texture. If it looks and smells perfectly normal, it is probably safe to use in a cooked application that will be heated. Do not serve cheese on a board or grate it on a plate without cooking it. For the pre-shredded Parmesan left overnight, discard.
Can I freeze parmesan cheese?
Yes, and parmesan is one of the best cheeses for freezing. Its very low moisture content means that the ice crystals do minimal damage to the texture when they freeze. A block of Parmesan is frozen for 12 to 18 months. Grated Parmesan freezes for 6 months. Best approach: Crush the block before freezing and store in a zip-top bag. Frozen grated Parmesan goes straight from the freezer into pasta sauce, risotto or soups without thawing. It really is one of the most practical freezer cheeses available.
Further reading
Better Living may earn commissions through affiliate links and may occasionally feature sponsored or partner content. If you make a purchase through our links, we may receive a small commission at no cost to you.
