Introduction to Espresso Bean Degassing and Blooming Methods - How Long is the Optimal Bean Degassing Period?

Have you ever experienced this? You purchased freshly roasted coffee beans, eagerly opened them to brew and taste, only to find the extraction unstable and the flavor presentation less than ideal. A few days later, when you brew again, it tastes much better. What's the reason for this? FrontStreet Coffee's article will help you understand what "bean resting" is all about.

Coffee Beans Are Too "Fresh" and Need Resting

After purchasing roasted coffee beans from FrontStreet Coffee stores, FrontStreet Coffee recommends letting them rest for a few days. Starting from the roast date, light to medium roast coffee beans should rest for 4-7 days, medium to dark roast for 7-10 days, and espresso beans for 10 days before brewing. This is because freshly roasted coffee beans often carry roasted smoky flavors, and under high temperatures, the beans store large amounts of carbon dioxide gas internally, which continues to be released after roasting. If you brew at this time, the unstable gases will "run rampant" and affect coffee extraction. For example, with pour-over coffee, when you pour hot water for blooming, the gas forms large bubbles that break through the coffee bed, indicating the coffee is "breathing" and releasing gas. The brewed coffee tends to have off-flavors and rough textures.

When using an espresso machine to extract fresh beans, the finely ground coffee powder under the machine's pressure and high temperature releases carbon dioxide along with the coffee liquid as golden crema. Besides reducing extraction rate by hindering contact between hot water and coffee grounds, excessive gas also increases the chance of channeling, causing uneven extraction in the early to middle stages. By the time the gas is released, the coffee puck is already overheated, leaving only bitter flavors in the later stages, and the resulting coffee taste is often unsatisfactory.

How to "Rest" Coffee Beans?

Degassing is a continuous process. If coffee beans release all their internal gas, it means they are no longer fresh, and naturally have almost no aroma. No matter how expensive the coffee beans are, if they're not fresh, the flavor will be greatly diminished. Therefore, you should try to drink coffee beans within their optimal flavor window. So how do we master this optimal resting period?

You should know that the darker the roast, the longer the heating time, and the more carbon dioxide contained in the coffee beans, thus requiring longer degassing time. This is especially true for dark roast coffee beans that have undergone second crack, which have the maximum expansion and accumulate large amounts of carbon dioxide gas. That's why when we store dark roast coffee beans, as the resting time increases, the gas will expand the outer packaging, indicating the coffee beans are continuously releasing gas. Bean resting is for "degassing" - letting the harsh flavors and off-notes escape, allowing the coffee's original flavors to emerge.

Actually, coffee beans you receive don't need much handling - no need to open the bag and transfer to a sealed container, and no need for refrigeration. Just leave them in their original packaging in a cool, dry place. Coffee bags are equipped with one-way degassing valves. When coffee beans release gas, the packaging bag will expand, and the degassing valve's function is to prevent the coffee bag from bursting while maintaining pressure balance between inside and outside. Then wait until the recommended resting period is over before opening to taste. FrontStreet Coffee reminds everyone: try not to squeeze out the gas inside. Due to the pressure difference between inside and outside the bag, coffee beans will accelerate gas release to fill the space. Of course, the coffee aroma we smell when squeezing the coffee bag is actually the loss of flavor compounds from the coffee beans.

Taking the coffee beans sold by FrontStreet Coffee as an example, when purchasing light to medium roast coffee beans, FrontStreet Coffee recommends resting them for 4-7 days, while medium to dark roast coffee beans need about 7-10 days to reach flavor stability. To ensure freshness, FrontStreet Coffee ships coffee beans roasted within 5 days, usually arriving in 1-3 days. This way, the coffee beans everyone receives are within their optimal flavor window, and you can start focusing on extraction techniques.

Why Do Coffee Beans Need to "Wake Up"?

Most coffee shops use medium to dark roast espresso beans to present rich, balanced flavors. To make dark roast beans remove uncomfortable bitterness, let remaining carbon dioxide escape, and use oxidation principles to make flavors more rounded and smooth, we appropriately extend the resting time while opening the packaging to "wake up" for several hours before use.

Here FrontStreet Coffee suggests that medium to dark roast espresso beans should rest for no less than 10 days, and the rested coffee beans should be exposed to air for 3-4 hours before use. FrontStreet Coffee wants to remind everyone about the details during wake-up: place coffee beans in a cool, dry, dark environment without strong odors, and shake and stir the coffee beans thoroughly every half hour so that the beans underneath can also come up to breathe fresh air. Use as soon as possible after wake-up ends. Try to wake up only as much as you'll use to avoid excessive wake-up that causes loss of aromatic components and flavor compounds.

Can You Brew Coffee Beans That Haven't Been "Properly Rested"?

After undergoing high-temperature roasting, coffee beans still retain smoky flavors internally. Directly brewing coffee beans that haven't been "properly rested" will show obvious degassing during extraction, and the coffee tends to have green, harsh flavors with unremarkable characteristics and an unclear, opaque mouthfeel. Therefore, FrontStreet Coffee believes bean resting is very necessary. But what if you really can't resist wanting to taste the coffee early?

Here FrontStreet Coffee has two small tips: during the brewing process, blooming is the most important degassing stage. We can extend the blooming process to let the coffee release more carbon dioxide. For example, if our normal pouring process has a 30-second bloom time, we can extend it by 10 seconds, starting the second pour at 40 seconds.

There's also another method: we can grind the beans and let them sit in the air for 1-2 minutes before brewing. Grinding increases the contact area between coffee and air, allowing gas to be released more fully. It's worth noting that what evaporates is not just carbon dioxide, but also small molecule gases that affect coffee flavor, which is why coffee needs to be brewed and consumed as soon as possible after grinding.

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Important Notice :

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