How Long Do Coffee Beans Last Once Opened?

A good cup of coffee needs to be brewed from fresh beans. Roasted coffee beans do not keep for long, especially after being opened. Here is how to make sure your coffee is always as fresh and delicious as can be.

How Coffee Goes Stale

Once the coffee can or bag is opened, the beans will come in contact with oxygen. This contact causes the beans to start to oxidize, which in turn causes the coffee to lose flavor.

Whole Bean vs. Ground Coffee

It is always better to purchase and use whole-bean coffee instead of preground. Grinding coffee beans speeds up the oxidation of the coffee and hastens deterioration. Even grinding beans the day before using results in poorer-tasting coffee.

Recommendation of "Cook's Illustrated"

The magazine "Cook's Illustrated" performed taste tests over a two-week period. After only 12 days, tasters noted that the coffee was not fresh. Their recommendation is to use opened coffee within 10 to 12 days.

How to Test for Freshness

To make sure your beans are still fresh, "Cooks Illustrated" recommends placing 1/2 cup of beans into a zip-top bag, squeezing out the air and letting them sit overnight. If the bag puffs up, that means the beans are still releasing carbon dioxide and are still fresh.

How to Extend the Life of Coffee Beans

Freezing coffee beans in small portions limits their exposure to moisture and oxygen, which keeps them fresher longer. It is important to divide the beans up before freezing so that they are not constantly being pulled from the freezer, measured out and the unused portion then refrozen.

References

• "Cook's Illustrated"; Secrets to a Perfect Cup of Coffee; Keith Dresser; Sept/Oct 2009