Any coffee aficionado can tell you that there’s a detectable difference between high- and low-quality coffee, even when you brew a simple cup at home. While your home coffee machine may not compare to café equipment, one thing you can do for your coffee's sake is think twice about buying beans from the grocery store.

Grocery store coffee can sit on the shelves for a long time, which seems okay, because the coffee's listed shelf life usually spans several months. However, coffee beans reach their peak flavor about 2 to 3 weeks after roasting, and begin to lose their flavor after that, a fact that most supermarkets don't pay attention to.

When buying coffee, focus on the “roasted on” date over the “best by” date, browse local roasters and coffee shops, and try to buy whole beans. Ground coffee oxidizes and changes in flavor a mere 20 minutes after grinding, so just imagine what pre-ground supermarket coffee is like after weeks of languishing on the shelf.