Tips for Buying and Storing Coffee
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.
BUYING AND STORING TIPS
- DO buy loose beans in small quantities no more than a few days from the roasting date (ask before you buy); our testing has shown that roasted beans are ready for the compost pile after just 10 to 12 days. Buy from a local roaster or a store that sells a high volume, upping 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 (the outer limit for beans in such packaging cited by roasters including George Howell Terroir Coffee Company, in Acton, Mass., and national retailer Peet’s Coffee & Tea). 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.
To determine how long coffee maintains ideal flavor after roasting, we bought 30 bags of beans (all from the same batch, packaged within hours of roasting in one-way valve bags). 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, where 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.