The aging of roasted coffee is linked to the rate it 

This is a complicated subject as coffees don’t degas at a fixed rate; there are many variables that impact the process. The key is to understand how and why coffee degasses, in order to find a storing method that works for you and your coffee.

Why does coffee degas?

Coffees degas because, upon roasting, CO2 and other gases are trapped within the bean. When you brew a coffee that is too freshly roasted, this trapped CO2 clashes with the water, preventing the flavour volatiles in the grounds from transferring to the cup.

In both whole bean and ground coffee, these gases are released (along with fragrances and aromas) over time, into the space around them. Again, the rate of this release is dependent on many variables.

Generally speaking, darker roasts typically tend to degas at a faster rate than light roasts. Lee Knuttila, the owner of Quietly Coffee, explains why this is.

“The more extensive the roast, the larger the craters and weaker the walls in the porous bean, so gas exits quickly. Moreover, the oily lipids exposed by darker roasts are susceptible to oxidation and prone to going rancid. Thus, because we have very little variation in flavour and a danger of rancid notes: drink it fresh and fast.”

Knuttila’s advice can’t necessarily be recommended for light and medium roasts though. In a light roast coffee, the dense structure of these beans remains intact resulting in a longer degassing period. It takes about 33 days for the beans to release their remaining CO2. Though this may seem like a clear window, Knuttila warns against sticking to it too closely.

“This is not necessarily the best window because as CO2 is leaving (and/or degrading), so are those flavour volatiles. Thus, for light and medium roasts, the best before (and after) date is inexorably tied to the very individual and specific
qualities imparted by origin and the roasting process.”

That can be a complicated equation to figure out. So, Knuttila suggests this timeline: light roasts are best consumed between 14-90 days and dark roasts should be consumed within 14 days of being roasted. Always remember that light and oxygen are roasted coffee’s worst enemies.

Store coffee in the original bag

Because coffee degasses faster when it is surrounded by oxygen/air, the easiest thing to do after you prepare your dose is to squeeze the air out of the bag, seal it, and fold it over so it is sitting in less oxygen and space to degas into. Remember that this method just reduces the speed at which it degases, and does not stop the degassing.

OPTION 2: Store it in a vacuum container

Continuing from the logic above, you can seal it in a vacuum container/ canister. If you have a vacuum sealer, you can seal the coffee when it is tasting its best, reducing the speed at which it degases.

OPTION 3: Vacuum seal and freeze it

The best way to do this is to vacuum seal (at optimum flavour) and then freeze it (as quickly as possible). Once frozen, the coffee should either stop degassing altogether or degas at an extremely reduced rate and essentially preserve it. When defrosting, the key is to transfer the coffee to your fridge to slowly defrost, reducing the chance of condensation. Then, let the coffee come to room temp in the sealed bag before you open it for brewing!

October 21, 2022 — Zara Snitman

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