We are often asked “how long does coffee last after production?” To answer this, we need to look at two very distinct issues: coffee durability and coffee freshness.
Coffee durability
Coffee durability refers to the usable life of the coffee.
This can better be illustrated by looking at the durability of a carton of milk left out on the shelf versus one left in the fridge. The former will have a very low durability because it will go sour very quickly, whereas the milk in the fridge will last a lot longer. The milk remains milk, but it changes form if left out and it is this change in form that defines whether it is still the same product you bought or not.
Coffee can be kept for years in a sealed container because it is dry and as long as insects or mould don’t get into it, the coffee will look the same and retain many of its characteristics for a long time.
So unlike milk that has been left out the fridge, or milk that is one month past, its sell-by date, coffee will look the same and pretty much taste the same even after 5 years on your supermarket shelf. Or will it?
Coffee freshness
Well, it will certainly look the same if it has been kept in an airtight bag, but that’s where the similarity ends because it certainly will not taste the same. The reason is quite simple: from the moment coffee is roasted, it starts to give off volatile compounds that are mixed in with the carbon dioxide that forms during roasting. The roasting process creates a lighter and more porous bean, and so the ability of the bean to release these gases is increased and it’s no wonder that opening a fresh bag of coffee, produces that wonderful aroma of coffee that soon fills a room!
The downside of this aroma release is that it continues for as long as the coffee remains in the bag. When coffee is roasted and comes out hot from the roaster, this gas release is excessive and for that reason, fresh roasted coffee is often left for a while in colling pans to allow the majority of the carbon dioxide to dissipate before packing. This is called degassing. Good quality coffee packaging has a one-way valve that allows the gasses to continually release from the bag, but not to allow air back into the bag because oxidation caused by oxygen, is the chief destroyer of the flavour profiles that coffee carries.
So you guessed it – this is the part that refers to coffee freshness. Drinking 5 year old coffee is unlikely to kill you, but it may dent your love for coffee when you taste a rather stale, flavour depleted cup of coffee.
How long does coffee taste fresh?
The afficionados will be quick to tell you that coffee should be roasted and consumed within a few weeks. They’d not be wrong of course, but the practicality of roasting, degassing, packing, shipping and then storing in supermarket warehouses or in café storerooms, means that this becomes difficult.
Then you have differences in the quality of the packaging and so thinner or lower quality coffee bags may let oxygen in. The quality of the gas valve (that slightly protruding round plastic part that is embedded in the bag) is also a key part of whether oxygen can enter the bag.
In our roastery, we monitor the freshness of coffee that we pack over time, and we can easily say that consumption within 6 months of packing offers you a flavour profile that is still fresh. After about a year, you start to see more significant changes in the aroma profile and so we set our shelf life at 12 months.
Life’s too short for stale coffee and so make sure that you’ll use your coffee within a year of its roast date to enjoy the flavour profiles and aromas that you were meant to enjoy.