How long do coffee beans last?
Coffee beans are the seeds of the coffee plant fruit – sometimes called a 'cherry' despite not being related to cherries. The ripe cherries are picked and the fruity covering removed, revealing the beans. At this stage, the coffee beans are very hard and durable, and if you were to try and bite through a raw coffee bean, you would possibly hurt your teeth! If stored correctly, green coffee beans can last a long time – up to two years.
Roasting the beans – which is exactly how it sounds, exposing the beans to steady heat for a set period of time – allows the flavour to develop, but also weakens the integrity of the bean. This is not a bad thing from a coffee drinker's point of view as it allows the beans to be crushed or ground much more easily! But it can make the beans brittle and liable to break under pressure, and also makes them liable to deterioration. Properly cared for (i.e. stored in a cool, dry place out of sunlight), roasted coffee beans will last up to nine months.
However, other factors affect how long coffee beans will last for. Good coffee beans have a thin film of natural oil that helps to protect the bean, sealing in the flavour and helping the coffee bean to last (again, they’ll need to be stored in a clean, air-tight container in a cool, dark place). Sunlight, heat, humidity and too much cold can all cause your coffee beans to degrade more quickly than they should.
When it comes to ground coffee, the timeframe is even shorter, with ground coffee staying fresh for just a few weeks. This is because grinding the beans to release that delicious coffee flavour is destructive to the bean, allowing much more air to interact with the coffee. For best results, grind a small number of beans as you need them.