> For an espresso, 1-2 weeks old is totally fine (even preferred?), but for pourovers the flavor is totally different even just 8-9 days after roasting.
Most sources suggest that the optimum flavor profile develops about a week after roasting, and drinking coffee brewed from freshly roasted beans to be comparatively flat tasting. Blind taste tests have also suggested that contrary to the popular belief, beans don't go stale after two weeks, but retain the same taste profile almost out to 6 months (assuming proper storage). The key difference is that older beans are completely degassed, and pourover techniques and drawdown times as well as grind size should be adjusted accordingly, something hard to do in most espresso machines but easy with pourover. An immersion brewing method is also less sensitive to degassing.
Most sources suggest that the optimum flavor profile develops about a week after roasting, and drinking coffee brewed from freshly roasted beans to be comparatively flat tasting. Blind taste tests have also suggested that contrary to the popular belief, beans don't go stale after two weeks, but retain the same taste profile almost out to 6 months (assuming proper storage). The key difference is that older beans are completely degassed, and pourover techniques and drawdown times as well as grind size should be adjusted accordingly, something hard to do in most espresso machines but easy with pourover. An immersion brewing method is also less sensitive to degassing.