Tuesday, 25th April, 2023
Often also referred to as “resting” or “degassing,” in the journey of coffee preparation, ‘aging’ of coffee is widely considered an essential step for the coffee beans to unleash their full flavour potential, and there are four critical factors that contribute to the overall enhancement of taste:
First and foremost, the release of carbon dioxide (CO₂) is crucial. As coffee beans are roasted, CO₂ forms within them due to the Maillard reaction and other chemical reactions. The process of degassing develops the coffee’s flavor profile, and if beans are brewed immediately after roasting, the high levels of CO₂ can result in a sharp, sour taste. To avoid this, let the coffee rest for 12-72 hours, which allows the CO₂ to escape and significantly reduces the chances of a sour, off-flavor in your final brew.
Secondly, oxidation plays a significant role. After roasting, the coffee beans are exposed to oxygen, triggering a slow oxidation process that helps to break down and stabilize various flavor compounds, resulting in a more balanced and rounded taste. However, storing coffee beans in airtight containers during the resting period is crucial to prevent excessive oxidation, which could lead to a stale or flat flavor.
The evaporation of volatile compounds is another essential factor. Roasting coffee beans produces hundreds of volatile compounds that contribute to the coffee’s aroma and flavor. Allowing the coffee beans to rest for a short period lets these volatile compounds settle and stabilize, enriching the overall flavor and aroma profile of the coffee.
Let’s get a bit more technical
From a scientific perspective, there are additional factors that contribute to the importance of resting coffee beans after roasting:
- Chemical reactions: During the resting period, the coffee beans continue to undergo a series of complex chemical reactions. These reactions can lead to the formation of new flavor compounds or the breakdown of undesirable ones. By allowing the beans to age, these chemical reactions have a chance to reach a stable state, which ultimately results in a more developed and nuanced flavor profile.
- Changes in acidity: The roasting process can lead to the formation or breakdown of various acids within the coffee beans, such as citric, malic, and phosphoric acids. These acids contribute to the overall acidity and brightness of the coffee. Allowing the beans to rest after roasting gives these acids time to reach an equilibrium, resulting in a more balanced acidity that enhances the overall flavor of the coffee.
- Melanoidin polymerization: Melanoidins are complex polymers formed during the Maillard reaction, which occurs during roasting. These compounds contribute to the color, aroma, and flavor of roasted coffee. After roasting, melanoidins continue to polymerize, and this process can contribute to the development of mouthfeel and the perception of body in the brewed coffee. Allowing the beans to rest enables this polymerization process to continue, ultimately enhancing the sensory experience of the coffee.
- Optimal brewing extraction: As previously mentioned, CO₂ release is an essential aspect of the aging process. However, this also plays a role in the brewing process itself. When coffee is brewed, CO₂ is released, which affects the efficiency of the water extraction of soluble compounds from the coffee grounds. A certain amount of CO₂ is beneficial, as it helps to create a uniform extraction. If the beans are brewed too soon after roasting, the excessive CO₂ can disrupt the extraction process, resulting in an uneven and less flavorful cup of coffee. Allowing the beans to rest helps achieve the optimal CO₂ balance, ensuring a better extraction during brewing.
In summary, for a more balanced and delightful coffee experience, the aging process of coffee beans after roasting is indispensable. By allowing for CO₂ release, oxidation, stabilization of volatile compounds, and adjustment of moisture content, you can elevate your coffee to new heights of flavor and enjoyment.
Posted by Ryan Godinho
Categories: Coffee Quality