We Brew Coffee

Unlocking the Secrets of Coffee Degassing: How to Brew the Perfect Cup

Coffee lovers all over the world crave a fresh and flavorful cup of coffee to start their day. One of the key components of a great cup of coffee is the degassing process that coffee beans go through after they are roasted.

In this article, we will explore what coffee degassing is, how long it takes, and how to tell if your coffee is fresh. We will also take a closer look at the factors that affect the degassing process, such as harvesting techniques, drying processes, bean size, and the type of roast.

Coffee Degassing

Degassing is a process that occurs when coffee beans release carbon dioxide (CO2) that has been trapped inside them during the roasting process. Coffee beans contain many different chemical compounds, including carbohydrates, amino acids, and oils, which all contribute to the flavor and aroma of coffee.

During the roasting process, the heat causes the chemical reactions that transform the raw green coffee beans into the aromatic and flavorful coffee beans that we all know and love. As a result of these chemical reactions, CO2 is produced, which becomes trapped inside the beans’ cells.

Why do coffee beans emit CO2 in the first place? The beans continue to emit CO2 because the gases produced during roasting are trapped inside the beans’ cells and need to escape.

If the beans are ground right after roasting, the CO2 will prevent the coffee from extracting correctly and result in under-extraction, leaving the coffee tasting sour and acidic. The release of gas is necessary for a better extraction.

How Long Does It Take?

The degassing time of coffee beans can vary depending on several factors. These factors include the type of coffee bean, the degree of roasting, the harvesting techniques, and the drying process. On average, coffee beans need between 3 to 7 days for the majority of the gases to release, but this time frame can be extended and vary based on the factors mentioned above.

Additionally, coffee beans typically continue to degas for up to four weeks after roasting, reaching a state of optimal freshness. How do you know if your coffee beans are degassed or still need time?

The Freshness Test

The freshness test can determine if coffee beans have degassed or need more time. The best way to tell if your coffee beans are ready for use is by performing the popping or crackling test.

After roasting, coffee beans will crackle and pop like popcorn because of the gases escaping. When the popping noises completely stop, you know that degassing is complete, and your beans are ready to use.

Another way to check your beans’ freshness is by examining the roast. An excellent freshly roasted coffee should still be shiny but not oily. Darker roasts may become progressively oily over time; this could signal that the beans are in the end stages of the initial degassing process. How do you keep roasted coffee fresh?


The key to maintaining the freshness of roasted coffee is to store it in an airtight container in a dry place where it is protected from oxygen and moisture. Keeping coffee in the freezer is not a recommended storage method since the moisture can affect the beans’ flavor, and making a vacuum seal with a CO2 pressurization might be necessary or beneficial.

Divide larger coffee bags into smaller airtight containers for increased freshness.

Brewing Fresh Coffee: The Bloom

When brewing coffee, you might have noticed a phase that is referred to as the bloom. Pre-infusing the coffee grinds causes this. The bloom is the result of gases released during the degassing process, primarily carbon dioxide.

The bloom is crucial because it helps to saturate all the grinds evenly, leading to a better extraction, resulting in a better-tasting coffee.

Factors Affecting Degassing

1. Harvesting techniques

The harvesting technique used to collect coffee beans can impact the degassing process. The essential part of harvesting is determining the right time to pick the coffee cherries.

Ideally, coffee cherries should be picked when they are ripe. Picking them too early or too late will impact the taste, and CO2 production may be affected.

2. Drying process

The drying process before and after harvesting can improve or damage the quality of the coffee bean. The drying process determines how long the beans hold moisture, which can affect the length of time required for CO2 release.

Inadequate drying can lead to inconsistent roasts and uneven degassing of roasted beans.

3. Bean size

Bean size can also affect the degassing process. The denser and smaller the bean, the longer the degassing process.

As coffee beans release CO2, they expand in size. Therefore, smaller beans need less time to degas than larger beans.

4. Type of roast

Lastly, the type of roast can influence the degassing process. Darker roasts release carbon dioxide for a more extended period than lighter roasts since the beans are heated for longer and at higher temperatures. The longer roast time will result in prolonged CO2 production.

The Importance of Degassing

Coffee is a complex beverage that derives its flavor and aroma from various chemicals that occur naturally in coffee beans. The degassing period is essential as freshly roasted coffee can be too fresh, and stale coffee can be just as bad.

During the degassing process, carbon dioxide is released from the beans, allowing the coffee flavor to develop fully. Too much carbon dioxide, however, can spoil the taste of the coffee.

The right level of CO2 in coffee enhances flavor extraction, but the presence of too much carbon dioxide can lead to a dull flavor profile. As the coffee degasses, it releases gases that can form air pockets between the coffee grounds.

These air pockets can undermine full contact between the water and coffee, leading to uneven extraction. Some degree of CO2 is extremely good for brew freshness, preservation, and crema.

The degassing period allows the coffee to reach an optimal state of freshness, promoting long-term preservation and enhancing the crema in espresso. However, pour-over and French press brews don’t need as much degassing because of longer extraction times.

Degassing Techniques

Patience is key when it comes to degassing coffee. Most coffee beans will take between three to seven days to degas fully. During this time, it is best to wait patiently for the coffee to reach its optimal state before brewing. Grinding fresh beans offers a shortcut to the degassing process, but it comes with a catch.

Grinding the beans before their degassing period is complete can ruin carbon dioxide and volatile compounds that enhance flavor. It is therefore advisable to allow coffee to degas before grinding to preserve the top notes.

Trial and error is often the best means of determining your coffee beans’ degassing time. Freshness tests and the appearance of the beans can help you determine when they are ready for use. You can also tell by the shiny but not oily appearance of the coffee beans.

Properly storing roasted coffee is crucial for preserving optimal freshness and flavor. The best storage method is to keep coffee in an airtight container and in a dry place, free from oxygen and moisture. This storage method can help extend the shelf life of your coffee.

Pre-infusing your coffee can allow remaining trapped carbon dioxide to escape to ensure fuller extraction. This is a process where you add a small amount of water to the bed of coffee grounds before the water passes through them. This process can improve the overall quality of your coffee brew by removing excess CO2.


Degassing is a crucial process in the coffee brewing process that can impact the flavor and aroma profile of your coffee. As we have covered, allowing coffee beans enough time to degas can help bring out the best flavors in your coffee. It is best to use trial and error, coupled with appropriate storage methods, freshness tests, and degassing techniques to get the best results.

Whether you are a coffee enthusiast or professional barista, understanding the importance of degassing and the various techniques that can be employed can help you achieve a great coffee brew every time.

As we have discussed in this article, degassing is an essential process when it comes to brewing delicious coffee. However, it is a delicate process that can be influenced by several factors.

It is crucial to understand these factors and how they affect the degassing process to achieve optimal coffee quality.

Factors Affecting Degassing

Harvesting techniques, drying processes, bean size, and the type of roast all affect the degassing process. Knowing these factors and how they affect degassing can help you determine the best degassing time for your beans. An example is larger beans taking longer to degas than smaller beans. By examining the bean size, you can estimate the time required for degassing, which results in an even extraction.

Importance of Degassing

Achieving the best flavor profile for your coffee requires patience and understanding the degassing process. An optimal degassing process improves flavor extraction, freshness, preservation, and crema. It is therefore vital to ensure balanced CO2 level in your beans for the best coffee flavor.

Degassing Techniques

Several techniques can help you achieve the perfect degassing process. If your beans are too fresh, you can grind them to speed up the degassing process. However, it is prudent to wait patiently until the beans are ready to preserve all the flavors. Proper storage of roasted coffee is crucial, and pre-infusing can improve coffee quality by encouraging the escape of excess CO2.

Experiment and Find the Best Degassing Time

Every coffee bean is unique, and their degassing times will vary depending on the harvesting technique, drying process, bean size, and type of roast. You can experiment by using different degassing times and storage methods to determine what works best for your beans. This experimentation is crucial in achieving the best coffee flavor possible. You can experiment with pre-infusing and freshness tests to determine your beans’ optimal degassing time.


Degassing is a delicate process that significantly impacts coffee bean flavor profile and aroma. Factors such as harvesting techniques, drying process, bean size, and type of roast all influence the degassing process. Appropriate storage, pre-infusing, and trial and error experiments can help you determine the best degassing time for your beans to achieve optimal coffee flavor. Whether you are a coffee enthusiast or professional barista, understanding the importance of degassing and the various techniques that can be employed can help you achieve a great coffee brew every time.

In conclusion, the process of degassing plays a crucial role in achieving the perfect cup of coffee. Understanding the factors that influence degassing, such as harvesting techniques, drying processes, bean size, and the type of roast, is essential for determining the ideal degassing time.

Through patience, experimentation, and proper storage, coffee enthusiasts can unlock the full potential of their beans and create a flavorful and aromatic brew. So, whether you’re a home brewer or a professional barista, remember the importance of degassing and its impact on the quality of your coffee.

Start your brewing journey with fresh beans, allow them to degas, and savor the rich and complex flavors that await you in each cup.

Popular Posts