It is often said that coffee should be – needs to be – freshly ground. It is one of our 7 steps to better coffee, and while the steps are all quite uncomplicated, they are all necessary to achieve a great result.
Coffee is a very volatile product, and one that is in constant change from the moment it is picked until the moment you drink it. Any number of things could happen to it on its way to you, and it is a testament to the people who work in every link of that chain that coffee can be as delicious as it is.
After it is roasted, it has a shelf life of around four weeks, provided it has been packaged well: cooled down quickly and as quickly as possible sealed in an dark container with a one-way valve, and even flushed with nitrogen to ensure that all the oxygen is gone.
Even after all this, the coffee should rest for a day or two (or perhaps as long as eleven days if it is an espresso coffee) before it is optimal. The clock is ticking. With every day, the coffee slowly loses a little bit of itself to aging.
The aging process comes mainly from exposure to oxygen and from drying out. How fast this happens is dependent on the surface area of the coffee bean and the ambient heat and moisture. A whole bean is small to begin with, but once ground, its surface area is multiplied somewhere around 200 times, and the aging process sped up accordingly.
All that lovely coffee aroma you get from freshly ground coffee – while lovely – won’t make it into the cup. Four weeks sped up 200 times would pass by in around 3 hours and 20 minutes. Luckily, it doesn’t quite scale linearly, and even waiting as long as 24 hours will yield acceptable results. But nothing beats freshly ground coffee.
A grinder is the most important coffee brewing tool, by far. Considering how far coffee has travelled, how many processes it has been through and how much hard work has been dedicated to bringing it to you, it would be a shame to grind it all up to then let it sit, its flavours fading away with every passing hour.
Roughly speaking, there are two types of grinders being sold as coffee grinders today:
One is basically a small blender – a container with a motorized knife mounted at the bottom. These grinders will not grind evenly, which in turn will lead to a less-than-good cup of coffee, as the coffee grounds will be over- and underextracted due to their difference in size. While cheap, these grinders should be avoided, as they are unsuited to grinding coffee.
The other type is a so-called burr grinder – either flat or conical. This type of grinder will grind fairly evenly, ensuring a good extraction of the coffee. Importantly, you will also be able to adjust the grind level, letting you fine-tune the cup of coffee you are making.
Using a grinder not only gives you a better cup of coffee from your beans, but also respects the coffee itself and the work that went into getting them to you in the first place.