Are You Sabotaging Your Coffee?

By the editors of Cook's Illustrated

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Your brew's quality may be suffering if you don’t buy and store your coffee beans properly. We'll show you how.

You can spend $20 a pound for premium coffee, but unless you’re mindful of roasting dates, bagging techniques, and expiration dates, you won’t get the most bang for your buck.

The Dos and Don’ts of Shopping for and Storing Coffee Beans

DO buy loose beans in small quantities no more than a few days from the roasting date (ask someone in the store before you make your purchase). Our testing has shown that roasted beans are ready for the compost pile after just 10 to 12 days. Also, buying from a local roaster or a store that sells a high volume ups your chances of buying beans from a recently roasted batch.

DO buy prebagged coffee in a heat-sealed, aluminized Mylar bag with a one-way degassing valve. This valve (sometimes no more than a bump) releases carbon dioxide to stop the bag from inflating while keeping out oxygen, which turns coffee stale. Unopened, these bags keep beans as fresh as the day they were roasted for up to 90 days (of course, as soon as you open the bag, the clock starts ticking on freshness).

DON'T rely on expiration dates. We’ve found some supermarket brands of coffee with expiration dates as far as two years out from the roasting date.

DON'T buy preground coffee. Grinding speeds oxidation and the deterioration of flavor. When we compared coffee brewed from just-ground beans with coffee brewed from beans ground 24 hours earlier, tasters overwhelmingly preferred the coffee brewed from freshly ground beans. Grinding the night before is also not optimal: Studies show the exposed coffee cells begin to break down within the hour.

How Long Does Flavor Last After You Open the Bag of Coffee?

To determine how long coffee maintains its ideal flavor after roasting, we bought 30 bags of beans (all from the same batch that were packaged in one-way valve bags within hours of roasting). Over two weeks, we used our haul to prepare two pots of coffee daily: one made with beans from a just-opened bag, the other using beans stored on the counter in a sealed zipper-lock bag with the air pressed out. A few very discriminating tasters noticed a change in taste after just a few days of storage; many tasters noticed a deterioration after 10 days; most tasters agreed the coffee tasted markedly less fresh after 12 days.

BOTTOM LINE: Opened beans stored in an airtight container should be used within 10 to 12 days.

Where to Store Beans: Counter, Fridge, or Freezer?

If you finish a bag of beans in less than 10 to 12 days, store them either in the original bag or in a zipper-lock bag away from heat and light. If you plan to keep beans longer than this time frame, store them in the freezer to limit contact with air and moisture. Never store coffee in the fridge—it will pick up off-flavors.

For the best results, portion beans (whether storing on the counter or in the freezer) in small zipper-lock bags in one-day allotments to keep air and moisture exposure to the barest minimum.

RECIPE FOR MEMBERS: Cream Cheese Coffee Cake

Our rich, moist cake boasts a lush texture as well as subtle acidity—a perfect backdrop for a tangy swirl of cream cheese filling. A crisp yet delicate coating of sliced almonds, sugar, and lemon zest forms a glistening, crackly crust on our perfect coffee cake.

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