Written by: Dušan Matičič, Head roaster at GOAT STORY
Fresh coffee is good coffee. But counter intuitively, fresh can be too fresh sometimes. Here's why you should rest your beans to get more flavor in your cup.
Green coffee has a moisture content of 10-12% and during roasting this moisture is released, leaving empty spaces that are filled with CO2 inside the bean. After the coffee is roasted, the CO2 begins to escape from the bean in a process called degassing. That is why coffee bags have degassing valves preventing them from exploding (literally).
Now CO2 by itself is not a problem. But it does mess with flavors in your cup because when freshly roasted coffee is ground, the release of the gas becomes quite violent and that causes problems with the extraction. CO2 and water don't like each other very much and CO2 actually pushes water away from the ground coffee, making it impossible for water to extract the good stuff from coffee.
Freshly roasted coffees cause glorious looking blooms, but don't forget to bloom a little longer with fresh roasted coffees to let CO2 escape.
That is why you might taste sourness, metal like tastes and violent acidity in fresh roasts. Freshly roasted coffees generally lack balance and simply feel »wrong«.
Leaving coffees to rest for a week or two will let the gas slowly escape and allow the true flavors of coffee to open up and find balance.
How long should coffee rest?
To get the most from your espresso (or turkish coffee), we recommend resting the coffee for at least 7-14 days after roasting.
Filter coffee is a bit more forgiving because of the longer extraction time. You can get a decent cup as quickly as a day or two after roasting, but we do recommend resting the coffee for at least 5-10 days after roasting.
It's important that you rest the coffee in a sealed bag/container. It makes sense to store it somewhere cooler, but most of us store our coffees in a kitchen cupboard or counter. That's perfectly fine!
Please do not store the coffee in the refrigerator though ... The fridge is a humid environment that speeds up oxidation of the coffee. That's not good for taste. And also if your coffee is not 100% securely sealed it starts to pull in aromas from the fridge quite intensely. And the last thing you want is your gentle Kenya Kiaga smelling of camembert or that leftover meatloaf on the top shelf.