Whole Beans vs Ground Coffee
All coffee produced is roasted before it is consumed; this roasting process brings out the flavour of the coffee by changing both the physical and chemical makeup of the beans. Once the coffee is roasted, left to cool, degassed and then packaged, the coffee beans are then stored in a cool dry place to preserve the freshness. Coffee beans themselves act like a container, locking in all of the flavours, and the aromatic oils that have developed through the roasting process. Once the beans are ground the flavour is exposed for the brewing, but if this brewing process doesn't happen soon after the beans are ground the flavour and aromas dissipate. Whole beans stay fresh much longer because there is less surface area exposed to the oxygen.
Grinding coffee yourself is not only the best way to enjoy the freshest coffee, it's also the first step in experiencing the aroma of the coffee even before you brew it. Ground coffee will begin to go "stale" within 15 mins, so it is best to purchase a grinder so that you can grind your beans as you require them, helping to preserve the oils and aromatic compounds.
Another way to prevent the ground coffee from becoming stale is to store the unopened bag in the freezer. When the coffee is required simply open the bag, measure out the required amount, then sqeeze out the air, seal and return to the freezer. If the coffee is to be used within a couple of days it is recommended that the coffee is stored in a cool, dry place, away from heat. The reason behind storing it securely and properly is to prevent air and moisture from reaching inside the bag causing the coffee to diminish in flavour and become stale.
Coffee tastes best if consumed 3 - 10 days after the beans have been roasted, depending on the blend, but the flavour can be preserved if stored effectively.
In conclusion, the general consensus is that it is better to purchase whole beans rather than ground coffee knowing that it deteriorates much quicker, however, if you must purchase your coffee ground then follow these guidelines to get the best out of your coffee.