Time passed since roast doesn’t always mean diminished freshness or flavor.
It’s the weekend and you’ve made some time to pop into our cafe. You walk to the wall of beans and scan over your options; setting your eyes on the roast or region you like, you choose a bag. A roast date is present and, to your shock, this coffee was roasted about two weeks ago. Hesitantly, you put the bag down and instead find the one with the freshest roast date. Satisfied with something fresher, you make the purchase and go home to start brewing.
While scouting for freshness should never be discouraged (quite the opposite, actually, it should be celebrated) we want to explain to you why that “two-week-old” coffee might actually be at its freshest, most delicious point in its life.
As a coffee bean is roasted, many of the sugars and acids within it convert to carbon dioxide (CO2) and release from the bean at various points in its journey. As CO2 develops in the bean, pressure builds until a sudden release, known to roasters as the first crack, allows a fraction of the gas to escape. As the roast develops (going from light to dark), the bean expands and allows more CO2 to escape. Even after the roast, the beans will expel this gas up until you finally brew with them! This residual carbon dioxide is the reason why that “older” coffee might actually taste better: a phenomenon known as degassing.
Degassing, or “gassing off,” is the time roasters give coffee to rest and let the carbon dioxide naturally release. This results in efficient and even brewing that will offer a sweeter and more balanced cup. While there are many factors that affect the rate at which a coffee degasses, a study has shown that one of the largest is the degree of roast as it directly affects the porousness of the bean. As an example, we’ve found through our cupping sessions that our Congo Hutwe Microlot, a much lighter roast, can reach the peak tropical fruit and tea notes as far as 10-14 days out of the roaster. While the coffee was roasted about a week ago, we don’t consider it ready to brew until it reaches a point we believe will be most enjoyable by our customers. On the flip side, our darker roasts are much more porous so they tend to gas off within a matter of days.
Hopefully with this information on hand, you’ll feel a little bit safer when shopping for any bag of beans from any coffee roaster. Always be cautious of the roast date on the bag when making a selection but be sure to find comfort in those ‘week old’ light roasts. Before the brewing process, degassing is one of the last factors that impacts the taste of the coffee so roasters should be taking this into consideration before the beans hit the shelf.
All this said, however, don’t forget that your barista wants you to enjoy your brew! Never be afraid to ask a question or two, chances are you’re not the only one and we are more than happy to help you get caffeinated.
by Zach Carey
03 August 2020
Information Sourced From:
Wang, Xiuju & Lim, Loong-Tak. (2014). Effect of Roasting Conditions on Carbon Dioxide Degassing Behavior in Coffee. Food Research International. 2014.01.027.