Whether you're ordering coffee in bulk to stay stocked up, or you just happen to find yourself with more coffee than you know what to do with, many people turn to freezing their coffee to make it last for the long haul.
At freezing temperatures foods break down more slowly, helping keep them fresh for longer periods of time. The same concept applies to coffee, which will slowly lose it's volatile flavor and aromatic compounds and eventually go stale if left out. Especially when enjoying specialty coffee, this can be a real shame.
Don't just go and toss your coffee bag in the freezer, though. Among the factors that determine coffee freshness, contact with oxygen and water are key players.
Oxygen rapidly oxidizes roasted coffee—that is, oxygen molecules will steal an electron from other molecules present in coffee and cause them to go stale or, worst, develop undesirable aromas or flavors.
Ideally, the coffee you're storing is whole bean, rather than pre-ground. Grinding coffee creates more surface area for oxygen to oxidize the roast. Regardless, sealing the coffee beans in an airtight container like a ziplock bag is critical to maintaining maximum freshness.
The other key is condensation. You don't want you coffee beans to come into contact with moisture until you're actually brewing it.
If you pull a can of cola out of your fridge or a tub of ice cream from your freezer right now, you'll notice a fine layer of water or frost will bead up on the exposed surfaces. Similarly, coffee beans pulled out from the freezer and exposed to air before they've returned to room temperature will attract condensation and begin to spoil.
So let's say you buy a 5lb bag of Joes Espresso, but won't use it all up right away. To maximize its freshness, you can break out the coffee beans into freezer-graze ziplock in week-sized quantities. Each week, pull out the next ziplock from your freezer, making sure to leave it sealed until the beans have warmed to room temperature.
Once they're warmed up, it's safe to open the bag and start using that coffee. Repeat weekly, and you can ensure enjoy bulk pricing on coffee without sacrificing freshness!