Coffee Degassing and Its Influence on Extraction
What is Coffee Degassing?
After roasting, coffee beans undergo a process called degassing, where they release carbon dioxide (CO2). This natural process, a post-roasting phase which the gas is released from the beans, can last for several days or even weeks, depending on roast level, bean type and other factors.
What Coffee Degassing Matters for Extraction?
Using coffee too soon after roasting can lead to excessive CO2 affecting the extraction process. Freshly ground coffee releases CO2 rapidly, causing uneven extraction. This unevenness, known as channeling, allows water to flow through the coffee unevenly, which can result in an inconsistent cup. You may taste under-extracted notes like sourness or weakness, or over-extracted bitterness and astringent mouthfeel.
How Does CO2 Content Impact Brewing?
High CO2 content in freshly roasted coffee can also cause excessive blooming during brewing, especially with methods like pour-over or espresso. This rapid gasses release can disrupt the brewing process, making it challenging to achieve an even extraction and potentially making it difficult to achieve a balanced cup. To avoid these issues, allowing the roasted coffee rest at least 7 days after roasting, depending on the roast level, before brewing will reduce the CO2 levels, and leading to a more stable extraction.
Does Roast Level Change the Degassing Process?
Darker roasts typically degas faster than lighter roasts due to the more significant structural breakdown of the beans during roasting. A light roast that hasn’t had enough time to degas, may be challenging to extract consistent flavors due to the lingering CO2. If there is a need to brew freshly roasted coffee, consider adjusting brewing parameters such as grind size, brew time, and temperature to accommodate the specific roast’s degassing stage.
How to Achieve a Balanced Cup?
Degassing plays a crucial role in how easily coffee extracts and can affect the taste of your cup. Allowing coffee to rest post-roasting and adjusting brewing parameters can help achieve a more balanced and consistent flavor.
Besides degassing, other factors like grind size, brewing method, and water quality also play a significant role in ensuring a perfect cup of coffee.
At 49th Parallel Coffee Roasters, we always provide fresh roasted coffee to our community. Check our FAQ to learn about how we roast and process coffee orders to ensure the freshness.