This is one of the most frequent questions that I get when talking to people who are interested in learning more about artisan coffees. My answer is often ambiguous, and here’s why.
Great coffee starts with exceptional coffee beans, from cherries picked only when they are at the peak of ripeness, and then processed and stored using methods that preserve their quality. Prior to roasting, coffee beans remain fresh for months, even years, though we typically purchase and roast the most recent crops as they become available from our importers.
When roasted, coffee goes through a complex transformation that activates the sugars and forms the aromatic and volatile compounds that we love in our beverages. The process begins with roasting, but it continues for weeks afterward.
To understand what happens to coffee flavor after roasting, think about a marathon performance by a symphony orchestra. When they first come on stage, they tune their instruments. This is like the first stage of coffee aging, just after it comes out of the roaster. An abundance of carbon dioxide is released during the first several hours, as the coffee “tunes in” to its flavor. Then as we hear the beginning of the concert, everyone is playing, but the string section is playing a particularly energized passage and play louder than everyone else, so we don’t notice the woodwinds or brass as much. In the first days after roasting, there are flavors and aromas that are more lively and pronounced, and these dominate the character of the coffee. After a few days, they have expended their energy, and other flavors emerge. That’s like a second passage for our imagined symphony where the string players, having spent much of their energy, are instructed to play quieter, and we hear more of the other sections. Over the next several days, the concert continues, and because they’ve been playing so long, all of our musicians are softening, playing quieter, and conserving their energy. This is like what happens to coffee. Once the flavors come into balance, the rate of change slows, but the overall flavor diminishes with time.
So to answer the question “how long do coffee beans last”, I typically tell people “at least a week, maybe two”.
Since I’m roasting coffee, I have plenty of beans around to experiment with. This morning, I decided to take a fine Columbian coffee that I roasted on November 6th, 18 days ago, and see how it would taste. The espresso shot displayed a decent amount of crema, but it didn’t last very long. The coffee strength was good, and I followed my regular recipe for an Americano. As a coffee, it tasted okay, but not great. As it cooled, it took on more of the characteristic flavor of a run-of-the-mill, pre-ground coffee. Drinkable? Yes, but nothing to write home about.
This experiment confirms my belief that coffee is best consumed within a week to 10 days after roasting. While it will last longer, you probably won’t enjoy your two-week-old coffee quite as much as just-roasted coffee. That’s why I think weekly deliveries of fresh, artisan-roasted coffee is the best way to enjoy every cup.