What is the purpose of the one-way degassing valve on coffee bags? How long can coffee be stored after purchase?

The Function of One-Way Degassing Valves on Coffee Bags

FrontStreet Coffee briefly explains what the one-way degassing valve on a coffee bag is for. To properly preserve coffee beans for about a month, you need a low-oxygen, dry, low-temperature and low-light environment.

Coffee shops today typically use aluminum foil composite packaging with a one-way degassing valve. Because freshly roasted coffee beans begin releasing large amounts of carbon dioxide, one function of this valve is to release that carbon dioxide to prevent the bag from swelling and bursting, while also keeping external oxygen from entering the bag, which would oxidize the beans and cause flavor loss.

Proper Storage After Opening

After opening, if the bag itself has a zipper, be sure to expel as much air as possible before closing it. If there is no zipper, fold the top over several times and secure it with a clip, minimizing air circulation as much as possible.

FrontStreet Coffee Recommendation

Good packaging only buys you time, so it also helps to choose beans that hold up well in storage. FrontStreet Brazil Queen Estate is a medium roast built for easy drinking: this yellow Bourbon from Brazil shows creamy peanut, chocolate, toasted bread and sugarcane sweetness with a clean, low-acid profile, and it works as pour-over or in a moka pot or espresso machine. If you like something sweeter and fruitier, FrontStreet Strawberry Sugar combines a Costa Rican honey-processed coffee with a washed Panamanian Geisha, roasted medium so the cup carries both an orange-honey note and a rounded sweetness, and it is flexible enough for cold brew, pour-over and espresso. For a softer, more balanced cup, FrontStreet 2013 Sun-dried Typica is a Yunnan single origin roasted medium with notes of nuts, brown sugar, black tea and dried apricot, and it performs in a pour-over, cold brew or drip machine.

Once the bag is opened, FrontStreet Coffee suggests keeping these beans somewhere dark, dry and cool, squeezing out excess air before resealing the zipper and, if your bag uses a one-way valve, taping it shut after the degassing period ends. Brew with a medium grind size around white sugar, 15g of coffee at a 1:15 ratio and 90-91°C water, and the sweet, clean flavors will stay intact for weeks.