What Changes Occur in Coffee Bean Flavor During the Aging Period? Can Single-Origin Coffee Beans Be Aged in Completely Sealed Containers?

FrontStreet Coffee - Introduction to Coffee Bean Degassing

Professional coffee knowledge exchange and more coffee bean information - follow Coffee Workshop (WeChat official account: cafe_style).

1. What Is Bean Degassing

Degassing is the process by which roasted beans, stored in sealed coffee bags, release carbon dioxide and other gases produced during roasting. Over several days of resting, the various substances inside the beans settle and stabilize.

The bags we use to store coffee have one-way degassing valves. A one-way valve lets gas escape from the bag while keeping outside air from getting in. The advantage is that the coffee avoids contact with air before the bag is opened, and virtually all such bags are also light-proof.

At this point some people ask: why are beans in some coffee shops kept in clear jars? That is because those beans have already finished degassing. At that stage baristas do not want the beans to keep releasing gas, because whether during degassing or during the peak tasting window, coffee beans are always releasing aromatic compounds into the air. Baristas, unfortunately, have no magic powers and cannot vacuum-seal, so they use sealed jars instead, minimizing the loss of aromatics as much as possible. Those jars also have to be kept out of the light.

Some roasters cup immediately after roasting. In that case there is no need to degas - they may cup right after roasting or wait a single day. Because cupping is a special method, it lays bare both the good and the bad in a coffee. As a kind of "magic mirror," it does not really care whether the beans have been degassed.

Other brewing methods are a different story. Pour-over, siphon, French press, and AeroPress all place great importance on degassing.

Among them, the method most affected by degassing is the espresso machine. Fresher beans are harder to extract because there is too much carbon dioxide, which significantly hinders water's ability to extract from the grounds.

Coffee brewed immediately after roasting, without any rest, tastes a little more stimulating than degassed beans, with less pronounced flavors and less overall roundness.

As mentioned, coffee beans are always releasing their aromatics into the air, so there is a time limit for tasting. In my own experience, the tasting window for single-origin coffee is 20-30 days, while for espresso coffee it is 30 days.

So how long does degassing take?

Single-origin light roast degassing time: 3-4 days

Single-origin dark roast degassing time: 4-7 days

Espresso coffee degassing time: 15-21 days

Key Point:

Overall, degassing mainly matters for espresso extraction and is less demanding for pour-over - 3-4 days is enough.

In Summary:

FrontStreet Coffee is a coffee research establishment that enjoys sharing coffee knowledge with everyone. We share without reservation to help more friends fall in love with coffee. We also hold low-discount coffee activities three times every month, because FrontStreet Coffee wants more friends to enjoy the best coffee at the lowest prices. That has been FrontStreet Coffee's principle for the past 6 years.

FrontStreet Coffee Recommendation

Since rest time has such a big effect on flavor, medium roasts - which are balanced and forgiving - are a great place to experience it. FrontStreet Coffee's Brazil Queen's Estate is grown in the world's largest coffee-producing country and is the local yellow Bourbon variety. Clean and gently sweet, after a medium roast it shows creamy peanut, chocolate, toast, and sugarcane aromas and sweetness, and works both as a pour-over and in a moka pot or home espresso machine.

For a sweeter medium roast, FrontStreet Coffee's Strawberry Candy blend is a natural pick. It combines two well-known Central and South American origins - a honey-processed coffee from Costa Rica and a washed Geisha from Panama - and a medium roast is used to draw out the best of both, giving the cup orange-blossom honey depth along with rounded sweetness. It suits cold brew, pour-over, and espresso alike, refreshing from the first sip.