No one enjoys stale coffee.
Stale coffee is like buttered toast that is allowed to sit for too long. While technically it’s still toast, we both know it’s really a waste of good butter. Just as toast is better when hot, coffee is better when its fresh.
But what does “fresh” coffee mean?
When it comes to defining fresh coffee, there seems to be an obvious answer, and sometimes the obvious answer is the correct answer. And then there are those times when the obvious answer isn’t the best answer. It might not be entirely wrong, just incomplete.
One would assume that coffee is the freshest immediately after it has been roasted. Technically, that would be true. A roasted coffee bean can never be fresher (that sounds a bit forward) than it is the moment after leaving the roaster. From that point forward the bean is on the path to staleness. Like the rest of us, it is only getting older with each passing day.
But I’m going to say something that may seem heretical: the freshest coffee is not the best coffee.
I know what you’re thinking … “But that’s not true when it comes to donuts.” And you would be right. The best donut is the freshest donut, assuming you eat donuts.
This is where understanding the science of coffee is important. Before you protest too much, let me assure you there’s no test involved.
This might seem obvious (see the paragraph above about the dangers of what seems obvious), but roasting a green coffee bean changes the chemical composition of the bean. Applying heat to the bean changes the color from a pale green to various shades of brown. But that’s just what you see on the outside.
On the inside of the bean, gasses are forming and trying to escape. In particular, carbon dioxide (yes, that carbon dioxide) is created during the roasting period and needs to be released in order for you to experience the true flavor of the bean.
Roasters refer to the period between the finished roast and optimal drinking as the “degassing” period. Simply put, this is the time when the gas is released from the bean. It’s also referred to as the “resting” period. While it looks like the beans are just lazily lying around, they are actually still at work letting off gas.
Imagine that, something that lies around emitting gas. I know, hard to picture.
But this degassing period is critical. If a grind still has a lot of carbon dioxide in it, the bloom will be really large and the extraction of flavor will be uneven. Here’s the catch: different beans degass at different speeds. Certain regions produce hard beans while other regions produce softer beans. In other words, there is not one set amount of time that is true for every bean or blend.
If you home roast, you can experiment with cupping on different days.
If you buy beans directly from a local roaster, just ask them how much resting period they use before bagging the beans. Most likely, they will start selling the beans at or near the best time to use them.
As a general rule, darker roasts degas faster than lighter roasts.
The degassing process is another reason to avoid (if possible) purchasing coffee that is already ground. Grinding the coffee speeds up the degassing process, which isn’t always a good thing because it might be circumventing the development of flavor. Let me put it this way — you might be getting cheated out of a better cup of coffee because you don’t want to grind your own beans.
So, whether or not coffee is fresh is an important question but not the most important question. Even more important is whether or not it has been properly degassed.
Now that will impress your friends.