It seems ironic, but the most burning coffee-related question I get asked is about the coldest place in the house: "Can I keep coffee in the freezer?" We conducted a blind side-by-side taste test to find out once and for all.
The canned (or, I guess, frozen?) response most coffee professionals give is No, because of how the freezer actually works. Your icebox preserves food both by removing the heat and evaporating the moisture that bacteria and mold love to grow in, allowing food to stay fresh longer, away from the flavor-destroying effects of decay. But the balance of moisture both inside and out of your coffee beans is pivotal and delicate: Mess with it, and you risk seriously altering and/or damaging their ability to brew their best.
So is the freezer really friend or foe?
Two pairs of samples came under scrutiny in our search for the perfect storage: Fresh vs. frozen whole beans, and fresh vs. frozen grounds.
All four were the same type and amount of coffee from the same fresh-roasted batch (24 grams of Finca Mauritania from El Salvador; roasted on August 30, tasted on September 1), prepared the same way (12 ounces of water at 200°F, brewed on a Bonmac cone—and, if you want to get really geeky about it, I poured the water through four ounces at a time).
The fresh beans brewed up as brown-sugar sweet with a slightly fruity sparkle, while the frozen ones made a vegetal, almost papery-tasting cup with a downright terrible aftertaste. Seriously, get this aftertaste out of my mouth.
(NB: Avoid putting still-frozen beans through a burr grinder. Moisture on your burrs is a one-way ticket to Rustville. If you must freeze definitely be sure to defrost.)
The preground samples, however, were a totally different animal. While the room-temperature-stored sample produced a noticeably "meh" cup that lacked sparkle and had a bitter finish, the frozen grounds turned into a cup of buttery, maple syrupy deliciousness—just as good as the fresh whole beans did.
Just like you, my first reaction was, "Wait...what?" But it kinda makes sense. Freezing directly after grinding allows the coffee to hang on to the delicate aromatics that start seeping out as soon as the beans get cracked open, while grinding and leaving at room temperature on a counter lets all the goodness float off into the atmosphere unchecked, rather than sticking around to bond with water and wind up in your mug.
"Great, but what does it all mean?"
Looking at the results with an open and caffeinated mind, my recommendation is to treat fresh-roasted coffee just as you would fresh-baked bread: Better to buy a little bit, use it up while it's fresh, and buy more when needed. And, just as with fresh-baked bread, the second-best—though by a mile—option is to prepare it into individual servings and store them air-tight in the freezer (in the case of bread, that means slices; for coffee, that means premeasured doses you'd use to make a certain size batch of joe at a time), using only what you need at any time and never letting them thaw and refreeze.
Do you freeze your beans? My mom sure does, and I gotta confess that it doesn't stop me from drinking whatever she brews up in her Mr. Coffee pot come Christmastime, either. Sometimes you gotta do what you gotta do.
About the author: Erin Meister (just "Meister" to friends and enemies) trains baristas and inspires coffee-driven people for Counter Culture Coffee. She's a confident barista and an audacious eater, but she remains a Nervous Cook.