Danmeng Cheng - Mar 06 2025
Why doesn't that amazing coffee work at home?
Many people have had this experience: tasting an amazing coffee at a cupping session, eagerly buying a bag, patiently waiting for it to rest, then excitedly brewing it with their favorite gear—only to be met with disappointment.
"Why does it taste off?"
"It’s not as good as the cupping!"
"Where’s the floral and fruity notes?"
"Did I just get scammed?"
I often receive similar questions from former students and industry friends: Why doesn’t my brew taste as good as the cupping?
So, let’s dive into the relationship between cupping and extraction.
Extraction Systems: Categorization
Whether it’s cupping, brewing, espresso, or other mainstream extraction methods, they all fall into two fundamental systems: immersion and percolation.
Most extraction methods are a balance of these two systems. The faster the flow rate, the more dominant percolation becomes; the slower the flow, the more immersion takes over.
Cupping (with a flow rate of essentially zero) is a classic example of a pure immersion system.
Espresso extraction relies more on percolation, though immersion still plays a minor role.
Brewing methods combine both systems, but the ratio varies depending on the equipment and technique:
● Clever Dripper leans towards immersion with some percolation.
● V60 is primarily percolation, with some immersion influence.
(While we focus on fundamental extraction principles here, modern competition techniques—like ultrasonic or vibrational immersion—apply external forces for unique effects. If you're interested, leave a comment, and we can explore them in future articles!)
Difference in Principles Between the Two Systems
Before discussing the extraction effects, we must first clarify the differences between the two systems.
1. Immersion System
As we all know, in an immersion system, water and coffee grounds remain relatively still during extraction, unless an external force (such as stirring) is applied. In other words, the coffee grounds stay in place, fully immersed in water, allowing the flavor compounds to be gradually extracted over time.
On the other hand, in a filtration system, water and coffee grounds are in relative motion. During the extraction process, water (or liquid) continuously passes through the coffee bed, rapidly extracting flavor compounds in a short contact time, eventually forming the brewed coffee.
In this process, the dissolution of substances in the immersion system mainly relies on one key factor: diffusion.
At the initial stage of immersion, since dissolution has not yet occurred in large quantities, the concentration of soluble compounds within the coffee grounds is very high, whereas the concentration in the surrounding water is very low.
As we know, dissolved substances naturally diffuse from areas of high concentration to areas of low concentration. Therefore, the soluble compounds within the coffee grounds migrate into the surrounding water. The water that first absorbs these compounds turns into a solution with a certain concentration. This solution then continues to diffuse its dissolved substances outward to areas where the concentration is still low.
Thus, within the immersion container, soluble compounds (in the absence of external forces) gradually migrate outward from the coffee bed, layer by layer. In this process, the actual concentration distribution within the immersion system resembles an onion—higher concentrations at the center and lower concentrations toward the outer layers. This phenomenon is known as a concentration gradient.
For example, many of us have brewed cold brew coffee or tea before. When coffee grounds or tea leaves are placed in cold water and left to steep in the fridge (or at room temperature), we often notice that the liquid around the grounds or leaves is the darkest, while the outer layers become progressively lighter. This is a clear manifestation of the concentration gradient.
At the beginning of extraction, this process works well.
However, as extraction enters the middle and later stages, challenges arise. As soluble compounds continuously dissolve and spread outward, the liquid in the container gradually reaches a certain concentration. This reduces the ability of the liquid to absorb more soluble substances.
Additionally, in an immersion system, water is typically added at the start and remains static throughout the process, without fresh water replenishment. As a result, the overall water temperature steadily decreases, further slowing down diffusion. This means the extraction capacity weakens over time, the rate of soluble compounds migrating outward slows, and the concentration gradient becomes more pronounced.
If this continues, the liquid surrounding the coffee grounds will eventually reach a concentration similar to that inside the grounds. At this point, the extraction process will slow down significantly or even come to a near halt. In other words, the concentration gradient that naturally forms in an immersion system can ultimately limit the overall extraction yield.
Take cold brew coffee or tea as an example. When we notice this concentration gradient forming, if we simply separate the grounds or leaves from the liquid and drink it immediately, the flavor is often weak or unbalanced due to the lower extraction yield (even stirring the liquid won’t improve the taste significantly). However, if we introduce an external force—such as shaking the bottle to mix the liquid evenly and then letting it steep a bit longer—the flavor improves, demonstrating how agitation can help mitigate the effects of the concentration gradient.
2. Filtration System
In a filtration system, since water continuously passes through the coffee bed, an additional factor—kinetic energy—plays a role in the extraction process. Compared to an immersion system, this added kinetic energy significantly influences extraction efficiency, second only to grind size.
Moreover, because water and coffee grounds are in relative motion, the concentration gradient does not form in the same way as in an immersion system. Each drop of water passing through the coffee bed maintains a strong ability to dissolve soluble compounds, ensuring that the extraction rate is not limited by saturation.
Thus, in this system, we can conclude that compared to the immersion system, the filtration system achieves a higher extraction yield.
Differences in Taste Between the Two Systems
In an immersion system, extraction occurs in an environment that naturally limits the extraction rate. As a result, the compounds extracted are primarily small and medium-sized molecules that dissolve easily. While larger, less-soluble molecules do dissolve, they do not dominate the final flavor profile.
Additionally, in traditional immersion methods (such as cupping), all the water needed for extraction is added at the beginning, and no external forces (like stirring or adding fresh water) are introduced throughout the process. This leads to a linear increase in concentration over time. However, since the extraction rate is limited, the final taste is largely dictated by the small and medium-sized molecules extracted early in the process.
On the other hand, the filtration system is more dynamic. With the added influence of kinetic energy and the absence of a concentration gradient, larger, less-soluble molecules continue to dissolve in the later stages of extraction. Additionally, since fresh water is continuously introduced, the overall concentration may not necessarily be lower than in an immersion system, but the resulting taste is cleaner and more vibrant, with flavors appearing more distinct and well-defined.
To make this easier to understand, let's use a simple analogy:
If an immersion extraction tastes like a mixed fruit juice, the flavor is rich and balanced. However, when too many types of fruit are mixed, the individual flavors blend together, making it difficult to distinguish exactly what fruits are in the juice.
On the other hand, a filtration extraction is more like a refreshing and clear fruit tea. The flavor might not be as rich as the immersion extraction, but the individual fruit flavors are distinct and layered. However, if there are too few fruits or the concentration is too low (like when the water flows too quickly), the flavor can seem too weak.
Thus, we can conclude that under the same extraction parameters, if we want higher extraction yields and clearer flavor profiles, the filtration system has an advantage. Conversely, if we want a more conservative extraction with a balanced taste, the immersion system is a better choice.
Application of Extraction Systems
Now, let's return to today's main topic: why do beans that taste great during cupping sometimes not taste as good when brewed?
The reason is that cupping is the extraction method most similar to a complete immersion system (although it's not entirely an immersion process, as the breaking of grounds and removal of grounds still involve some kinetic energy). So, if a particular bean tastes great during cupping, it's likely because the bean is well-suited to the low extraction rate and balanced flavor profile that immersion extraction provides. However, if we use a method where filtration plays a larger role (such as a fast-flow filter or espresso extraction), the higher extraction rate and more pronounced flavor layers might not suit that bean as well.
In such cases, adjusting the extraction method to include more of the immersion system (for example, using slower-flow filters, Aeropress, Clever Dripper, French Press, or even cold brew or ice-drip methods) is likely to yield better results. The immersion system tends to have a lower extraction rate, which can make beans that are less tolerant of high extraction rates (like low-altitude or dark-roasted beans) taste cleaner.
Furthermore, while the immersion system might not highlight flavor complexity as much as filtration systems, it often provides a more balanced overall taste. So, for beans that are not very complex in flavor (like washed coffee beans), increasing the proportion of immersion in the extraction process can also be beneficial. Here, "immersion" doesn’t necessarily mean a completely submerged process—some slower-flow filter methods can still have a higher immersion ratio.
In filtration-dominant systems, especially fast-flow filters, the extraction rate is easier to achieve at higher levels, and the flavor layers become more distinct and clear. This makes filtration methods particularly suitable for beans that are more tolerant of higher extraction rates, such as high-altitude beans or those with complex flavor profiles (like special processing methods or fermented coffees).
This is one of the reasons why, in recent years, we've seen a trend in professional coffee competitions where, even as the quality of the coffee beans continues to improve, many competitors are opting for faster brew times and larger brew ratios (like with espresso). These adjustments allow the coffee to express its complexity more effectively, taking advantage of the filtration system’s ability to extract more and highlight those intricate flavor profiles.
Conclusion
Many people have likely heard that cupping should be done before extraction. We’ve also seen many professional competitors, especially in the compulsory brewing stage of brewing competitions, conducting cupping before brewing. However, most people may not fully realize what exactly they are evaluating during this process.
From my personal cupping experience, I adjust my expectations based on the intended purpose of the coffee beans I am selecting.
If I am choosing beans for espresso, I may not necessarily select the sample with the brightest acidity and the most complex, elevated flavors—assuming there are no roasting defects in the samples. Instead, I tend to choose a coffee that tastes balanced and clean but seems to have a slightly lower extraction potential (or one that I feel could achieve a higher extraction).
This is because, under the high extraction yield of an espresso filtration system, such beans have the potential to be further developed. Additionally, in espresso’s high concentration format, flavors that seemed relatively muted during cupping may become more pronounced and clear due to the increased concentration, rather than being overly complex and burdensome to drink.
If, during cupping, I taste a sample that has a low extraction yield but presents dense, yet unclear flavors, it suggests that the coffee requires a higher extraction rate to achieve better balance and enhance its flavor clarity.
For this type of bean, if it already tastes this rich in an immersion-style cupping setting, brewing it into espresso—at ten times the concentration—will likely make the flavors overwhelmingly intense, making it difficult to enjoy. In such cases, I would opt for a pour-over method instead and use a fast-flow filter dripper to enhance extraction efficiency.
On the other hand, if a coffee’s acidity, flavor, and extraction yield are all well-presented, clear, and clean during cupping, it indicates that its extraction rate in immersion brewing is already near its optimal level. In this case, I would likely increase the immersion time during extraction, perhaps by choosing a slower-flow dripper or even an immersion-dominant brewing device.
In summary, cupping before extraction is the fastest way to understand a new coffee. It helps us determine a bean’s tolerance for different extraction rates and guides us in choosing the right concentration for optimal flavor expression.
So, if your extracted coffee doesn’t taste as good as it did during cupping, try adjusting your extraction approach—you might end up with a surprisingly delightful result!
Author
Danmeng Cheng – Technical Manager, MHW-3BOMBER
Danmeng Cheng is a seasoned coffee expert and Technical Manager at MHW-3BOMBER, with extensive experience in global coffee competitions. She is a WBC & WBrC Certified Sensory Judge, CQI Q-Arabica Grader, and SCA Certified AST. Since 2019, she has served as a WCE World Stage Sensory Judge, and she continues to judge the Chinese Barista & Brewers Cup Championships. With her deep expertise, she ensures MHW-3BOMBER’s products meet the highest specialty coffee standards.
