Parmesan Cheese: How Long Does It Last?

Parmesan cheese is a hard cheese made from skimmed, unpasteurized cow's milk, with a nutty flavour. It is a popular addition to pasta sauces, casseroles, and soups. But how long does it last? Well, the answer depends on how it is stored and whether it has been grated. If stored properly, Parmesan can last for several weeks to months.

Storing an unopened block of Parmesan in the fridge

Parmesan cheese has a long shelf life, especially when stored properly. An unopened block of Parmesan can last for several months beyond its expiration date.

When storing an unopened block of Parmesan in the fridge, it is important to ensure that the cheese is well-sealed. This will prevent it from drying out or absorbing odours from the refrigerator. You can wrap the cheese in parchment paper, cheesecloth, cheese paper, or wax paper, and then place it in the refrigerator. It is also recommended to cover the cheese block in plastic wrap or aluminium foil for added protection.

By storing an unopened block of Parmesan in this way, you can expect it to last for up to nine months in the refrigerator.

Additionally, it is worth noting that Parmesan cheese is a hard cheese with a low moisture content, which contributes to its longer shelf life compared to softer cheeses.

How long does grated Parmesan last in the fridge?

Grated Parmesan cheese can last for quite a long time in the fridge, depending on how well it is stored.

If you've bought pre-grated Parmesan cheese, it will likely last for 10 to 12 months in the refrigerator after it has been opened, as long as it is stored in an airtight container or heavy-duty freezer bag. This will ensure that the cheese doesn't dry out or absorb odours from the refrigerator.

If you are grating the Parmesan cheese yourself, it may have a shorter shelf life. However, if you store it properly, it should still last for several weeks to months. Wrap the cheese tightly in parchment paper and then in foil, or place it in an airtight container or resealable bag.

Regardless of whether you are using pre-grated or freshly grated Parmesan, always check for any signs of spoilage, such as mould growth, off odours, or changes in texture. If you notice mould on the surface of the cheese, it is generally safe to cut off the affected portion and use the rest of the cheese.

Freezing Parmesan

Parmesan cheese can be frozen for up to 18 months. It is one of the few cheeses that can be frozen, thanks to its low water content, which means the taste isn't affected in the same way as other cheeses. However, freezing Parmesan will result in a change of texture, and the cheese will become more crumbly.

To freeze Parmesan, first cut the cheese into portion-sized blocks. Then, decide whether to grate the cheese or freeze it as a block. If grating, use the finest grater possible as this will help the cheese withstand the freezing process. Place the grated or solid cheese into an airtight container. Seal the container and place it into a freezer bag. Label the bag with the contents and date, then place it into the freezer.

When it comes to defrosting, Parmesan should be removed from the freezer and placed in the fridge 24 hours before you need to use it. The defrosting process can take several hours, and will depend on the size of the block.

It is not recommended to refreeze Parmesan.

Signs of spoilage

Parmesan cheese is a hard cheese with a long shelf life. However, it can still spoil, so it's important to know the signs of spoilage to ensure you're consuming safe and tasty cheese. Here are some detailed signs of spoilage to look out for:

Mould Growth

Mould growth is one of the most common signs of cheese spoilage. If you notice any mould on the surface of your Parmesan cheese, it's essential to take action. Firstly, determine the type of mould. If it is a soft, fluffy mould, it is unsafe to consume and the entire cheese should be discarded. However, if the mould is hard and dry, it can be safely cut away. Remove at least 1 inch (2.5 cm) around and below the mouldy area to ensure all traces of mould are removed. The remaining cheese should still be usable.

Off Odours

Another sign of spoilage is an off or unpleasant odour. If your Parmesan cheese has developed a pungent or ammonia-like smell, it has likely gone bad. Trust your nose—if it smells unpleasant or very different from its usual nutty aroma, it's best to discard the cheese.

Changes in Texture

Parmesan cheese is known for its hard and dry texture. If you notice any significant changes in texture, such as the cheese becoming wet, sticky, or slimy, it has likely spoiled. This can be a result of improper storage, allowing moisture to affect the cheese. Dry, hard cheeses like Parmesan are susceptible to moisture absorption, which can lead to texture changes and mould growth.

Discolouration

While Parmesan cheese naturally has a yellow hue, any noticeable changes in colour could indicate spoilage. Keep an eye out for dark spots or discolouration beyond the typical ageing process. If the cheese appears to be turning a darker yellow or brown, it may be past its prime.

Clumping

Freshly grated Parmesan cheese is particularly prone to clumping due to the increased surface area. While clumping does not necessarily indicate spoilage, it can affect the flavour and texture of the cheese. To prevent clumping, store grated Parmesan in an airtight container and try to use it within two weeks of grating or opening pre-grated cheese.

In summary, always inspect your Parmesan cheese for any signs of spoilage before consumption. Mould growth, off odours, changes in texture, discolouration, and clumping can indicate that your cheese has spoiled. When in doubt, it's best to discard the cheese to avoid any potential health risks.

Storing Parmesan at room temperature

Storing Parmesan cheese at room temperature is not recommended for more than two hours. Parmesan is a hard cheese with a long shelf life when stored properly, but it is best kept in the refrigerator or freezer to prolong its freshness and flavour.

When stored at room temperature, Parmesan can remain edible for a few hours to a few weeks, depending on the ambient temperature and humidity levels. However, it is important to note that the quality and flavour of the cheese will deteriorate over time. The cheese will begin to dry out, and its texture and taste will change.

To maximise the shelf life of Parmesan cheese at room temperature, ensure that it is sealed tightly in its original packaging or wrapped in parchment paper and then foil. This will help to protect the cheese from moisture and outside contaminants. However, even with proper wrapping, the cheese will not last as long as it would if stored in the refrigerator or freezer.

If you plan to consume the Parmesan cheese within a few hours, storing it at room temperature should not cause any issues. However, for longer-term storage, it is best to keep the cheese in the refrigerator, where it will last for several weeks to months, or in the freezer, where it can be stored for up to a year.

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