(not grinding till the last moment is the best idea....unless u cant grind em properly)
"Coffee loses aroma and flavour with storage, as the volatile components evaporate. Coffee beans are considered as fresh,generally, 14 days after roasted. It is suggested to grind right before brewing to get the best results since aroma components are lost by to 50% after 5 minutes being grinded. Roasted coffee can be stored for some time, depending on roast degree, also other factors like UV light, humidity,etc.Vacuum-packing is not proven to extend storage life significantly.It is always better to buy small amount of coffee only for a short period, for example one week. No matter what methods are used to preserve roasted or ground coffee, aromas will still escape through time so there is not yet a method that can store coffee permanently without degradation of flavour. Some may suggest freezing roasted coffee beans to extend the shelf life, however, care must be taken of that no water droplets condenses on the coffee. Otherwise much aroma will be lost. One suggested approach to freeze coffee beans is to double-warp the package and allow it to defrost for at least 30 minutes before opening the package. This can decrease the change that any water condenses on coffee beans. It is important to understand that no methods can preserve coffee aroma up to full extent or extend its shelf life miraculously. The best method is to buy little amount of coffee every time and consume it as soon as possible. Some people suggests that ageing coffee beans for 3 days will allow aroma to develop to full extent. It is not always true since every type of coffee beans is different. Also, the ageing time of a type of coffee beans differs when the roast degree is different. Generally, the darker the roast, the short the ageing time, if any, is needed."
Had to post this again cos it didnt appear in the big coffee thread