All About Parmesan cheese
Your complete guide to parmesan cheese - discover how to store it properly, identify when it's gone bad, and find the best substitutes for your recipes.
How Long Does Parmesan cheese Last?
Storage times and freshness tips for parmesan cheese in different conditions.
Safety first: This guide provides general information. When in doubt, throw it out! Trust your senses and err on the side of caution. If something smells, looks, or tastes off, don't consume it.
opened pre-grated/shredded in fridge1-2 weeks
Signs of Spoilage
Significant clumping, moisture accumulation at the bottom of the container, noticeable discoloration, visible mold growth, strong sour or rancid smell.
How to Check
Visually inspect the cheese for any signs of clumping, discoloration, or mold. Perform a sniff test for off-odors. The texture might feel overly damp or slimy. Unlike block cheese, mold on grated cheese means the entire batch should be discarded due to its larger surface area.
Storage Tips
Transfer any unused grated Parmesan to an airtight container or a heavy-duty freezer bag to minimize air exposure and prevent moisture absorption from the fridge. Use a clean, dry spoon to scoop out portions to avoid introducing contaminants.
unopened pre-grated/shredded in fridge1-2 months (or until 'best by' date)
Signs of Spoilage
Clumping of the cheese due to moisture accumulation, discoloration (darker yellow or orange), visible mold growth, sour or rancid smell, overly moist texture.
How to Check
Visually inspect the package for any signs of clumping, discoloration, or mold. Perform a sniff test for off-odors. Squeeze the bag gently to check for excessive moisture inside.
Storage Tips
Pre-grated Parmesan often contains anti-caking agents and preservatives, which extend its shelf life compared to freshly grated. Always adhere to the 'best by' date. Keep the package sealed until ready to use.
opened block in fridge3-6 weeks
Signs of Spoilage
Visible mold growth (often green, blue, black, or white fuzzy spots) on the surface or cut edges. Excessive drying and hardening to the point of being brittle. Strong ammonia-like, sour, or rancid smell. Slimy or wet texture on the surface.
How to Check
Visually inspect all surfaces, especially cut areas, for mold. Touch the cheese to check for sliminess or unusual softness. Perform a sniff test for any pungent, sour, or off-putting odors. If mold is present, cut off at least 1 inch (2.5 cm) around and below the moldy spot; the remaining cheese is usually safe to eat due to Parmesan's low moisture content.
Storage Tips
To maximize freshness, wrap the block first in parchment or wax paper (to allow it to breathe slightly and prevent sweating), then tightly in plastic wrap or place it in an airtight container. Avoid direct contact with plastic wrap for extended periods as it can trap moisture and encourage mold. Store in the cheese drawer or a less cold part of the fridge.
block or grated in freezer6-12 months
Signs of Spoilage
While frozen, it won't spoil in the traditional sense, but quality can degrade. Signs of poor quality include freezer burn (dry, discolored patches), a significantly more crumbly texture after thawing, or a diminished flavor profile.
How to Check
Visually inspect for freezer burn before thawing. After thawing, check the texture – it may be more crumbly than fresh. Perform a sniff and taste test (small amount) for any off-flavors or lack of characteristic Parmesan flavor.
Storage Tips
For block Parmesan, wrap tightly in plastic wrap, then foil, and finally place in a freezer-safe bag. For grated Parmesan, store in an airtight freezer-safe bag or container, pressing out as much air as possible. Freezing may alter the texture, making it more crumbly, which is ideal for grating over dishes or incorporating into cooked recipes. Thaw in the refrigerator before use.
unopened block in fridge6-12 months (or until 'best by' date)
Signs of Spoilage
Extreme dryness or hardness beyond its normal state, very strong ammonia-like or sour off-odor when opened (rare for unopened), visible mold growth (very rare if properly sealed).
How to Check
Visually inspect the packaging for any signs of damage or punctures. When opened, perform a sniff test for any off-odors. The cheese itself should look consistent with a healthy block of Parmesan.
Storage Tips
Parmesan is a hard, aged cheese, making it highly resistant to spoilage. Always store it in the coldest part of your refrigerator. Follow the manufacturer's 'best by' or 'use by' date as a primary guide.