A first decision in drinking coffee is how and where to buy the beans. The decision is complicated by roasted coffee’s vulnerability to staling. Freshly roasted coffee is at its best about a day out of the roaster. If it is kept in an airtight container as whole, unground beans, it can remain splendid if ground and brewed in a week to ten days. But by three weeks out of the roaster, if not frozen or preserved in special packaging, even whole bean coffee is well on its way to listless mediocrity.
Retailer strategies differ on how to deliver whole beans to consumers economically and as fresh as possible. One way is to roast the coffee and sell it within a week after roasting. Freshly roasted coffee naturally degasses or emits carbon dioxide. This slowly discharging gas protects the beans from penetration by oxygen and consequent staling. Roasters both small and large pursue this "roast it and move it" approach. When a coffee stays around too long owing to unexpected buying patterns, the store may start brewing it as the "coffee of the day" until its gone, or even donate it to a food bank or charity.
However, the roast-it-and-move-it strategy demands discipline and a deep commitment to coffee ethics. Other roasters take a less risky but more expensive route: Immediately after roasting they seal the whole-bean coffee in bags that have been flushed with inert gas to chase out oxygen. Thereafter the carbon dioxide produced by the coffee slowly trickles out a one-way valve, further defending the coffee against staling.
Such gas flushed valve bags are remarkably effective in preserving coffee freshness. Manufacturers of the bags claim that they preserve flavor and aromatics for up to three or more months. In fact, most responsible coffee sellers take no chances and aim at about six to eight weeks. The one problem with such bags: When the coffee first emerges from the bag it tastes roaster-fresh. But thereafter it seems to degrade in flavor a bit more rapidly than freshly-roasted coffee.
The absolutely most responsible approach is pursued by roasters who pack their coffee in valve bags, but date the bags and pull them off the shelves after about three weeks.
Simply because coffee is sold as whole beans in bins does not mean it has not seen the inside of a valve-bag, by the way. Many large roasters, Starbucks included, ship their coffee to their stores in five-pound valve bags, which are then opened and dumped into the bins.