The coffee bag displays two important dates: the roasting date and the packaging date. Many brands only indicate the expiration date and forget the other two values that are so important to the brewing process.
Being aware of the roasting date is essential for successfully brewing coffee, since freshly roasted beans release gases in a process called degassing, making it difficult for a cup of coffee to be prepared immediately after roasting. A sufficient and timely release of the carbon dioxide contained in the beans must take place first.