Allowing Coffee to “Rest”

While it may sound strange, if you want to consistently get the best flavors and aromas from your freshly roasted coffee, you need to allow it to “rest”.  Simply put, this means waiting to brew the coffee.  

Roasting coffee causes complex chemical reactions to take place within the coffee seed. One byproduct of these chemical reactions is the formation of CO2, or carbon dioxide, within the roasted coffee seed.  If you have ever purchased a bag of coffee that was roasted within a day or two, it is common for coffee bags to have an inflated appearance due to the off gassing CO2.  The pressure builds in the bag until it escapes from the one-way valve.  High levels of CO2 make extracting coffee well much more difficult and will cause the results to vary daily until the coffee has sufficiently degassed.  If you have ever brewed really fresh coffee as a pour over, you will often see it rapidly swell in appearance like a volcano and bubble.  Ideally, what we want is the bed of coffee to remain flat throughout the brewing process so that the water evenly flows through the bed of coffee rather than channeling through open fissures, or cracks, in the bed of coffee.

Allowing coffee to rest improves the flavors and aromas when brewing freshly roasted coffees.  It is not uncommon to detect flavors and aromas in freshly roasted coffee that dissipate within the first few days.  Sometimes these novel flavors and aromas are enjoyable but often they are not and they obscure the flavor and aroma attributes the roaster describes on the bag of coffee.  Coffee is often described as “opening up” and mellowing out after a few days of resting.  This is simply a way of describing this phenomenon of allowing the coffee to age. 

How long should you wait? The answer depends on the roast level, the particular coffee, how you intend to brew the coffee, whether it is in whole bean form or ground, and whether you enjoy experiencing the subtle changes of the aroma and flavor of a coffee over time or if you want a coffee with a more stable flavor profile. Generally speaking, lighter roasted coffees take longer to degas than darker roasted coffees. If you are brewing the coffee as espresso, best advice is to wait seven days for whole bean darker roasts and around fourteen days for who bean lighter roasts. If you are brewing filter coffee or using an immersion brewer, best advice is to wait at least three days for whole bean darker roasts and at least five days for whole bean lighter roasts. Ketch Coffee Roasters extensively tests every coffee we sell and can provide you with our recommendations for how long you should allow the coffee to degas before brewing, but at the end of the day part of the joy of specialty coffee is learning to discover your own preferences through experimentation. Ground coffee degasses at a much faster rate than whole bean coffee, which is a double edged sword. While it will be ready to drink much sooner, it will also stale more rapidly than whole bean coffee.

If you are interested in learning more, we would recommend this resource from Seven Miles.