What is the coffee basis for judging extraction by taste?
Under-extracted coffee tastes sharply sour, noticeably salty, thin, and short on aftertaste. Over-extracted coffee turns bitter, with that bitterness crowding out other flavors. The reliable coffee basis for judgment is what the palate actually registers, not whether a brew lands inside the Golden Cup numeric range.
Numbers can mislead because bean quality and coffee bean processing shift results: a cup inside the Golden Cup window may still taste poor, and one outside it may taste fine. Sour, sweet, bitter, and salty balance and restrain each other, so a good cup keeps all four present. Adjust grind, ratio, or time based on the specific defect detected.
Judging whether a cup of coffee tastes good varies from person to person, but when it comes to the defective flavors caused by extraction problems, people often reach a consensus. This article, from the perspective of Front Street, introduces the specific taste manifestations of under-extraction and over-extraction. When under-extracted, coffee exhibits sharp acidity, noticeable saltiness, lack of aftertaste, and thin flavor; over-extraction causes bitterness to greatly suppress other flavors. The article also specifically reminds us not to rigidly adhere to the Golden Cup extraction values, because bean quality and processing methods can cause deviations from theory, and ultimately the real feeling on the palate should be the basis for judgment.
Although everyone has their own opinion on what "tastes good," when it comes to bad coffee, people's feelings are often surprisingly unanimous. So when something goes wrong in the extraction process, the problem is directly reflected in the taste, becoming a "defect." As long as we can identify this defect, we can infer what exactly went wrong with the extraction of this cup and then take targeted measures to adjust it.
But first, let's be clear: although the Golden Cup extraction theory sets ranges for under-extraction and over-extraction, we had better not judge the degree of extraction solely by numerical values. This is because factors such as bean quality and processing methods can cause deviations from the Golden Cup theory—coffee falling within the Golden Cup range is not necessarily delicious, and coffee outside the Golden Cup range is not necessarily bad. Ultimately, we should return to the real feeling on the palate and use it as the fundamental basis for judgment. Alright, next Front Street will first talk about what manifestations under-extracted coffee has.
Under-extraction Under-extraction means hot water fails to fully bring out the coffee substances, so the resulting coffee, due to its low substance content, exhibits the following conditions: Prominent, sharp acidity: Sour, sweet, bitter, and salty are the four tastes we can extract from coffee. These four tastes are both opposed to and restrained by each other, so in a cup of coffee, none of them can be absent. Think of coffee as lemon tea—a delicious cup of lemon tea, besides the sourness of lemon, the sweetness of fructose is also indispensable, because only with fructose added is the high acidity of lemon softened, making the whole cup acceptable. Front Street mentioned in yesterday's article that these four tastes, due to differences in molecular size, have different dissolution rates, so a complete extraction is needed to let each of the four tastes have enough quantity to contend with the others. When under-extracted, the coffee is filled with a large amount of acidity, because it has the fastest dissolution rate. Once it loses the checks and balances of other tastes, the acidity becomes particularly prominent and sharp due to excessive quantity, causing discomfort. Conversely, a lack of sweetness, or a lack of the mellow sensation brought by bitterness, is also a manifestation of under-extraction.
Saltiness appears and is noticeable: Unlike umami, saltiness, although weak in presence in coffee, does exist. It's just that its proportion in coffee is not high, and it is hard to detect under the cover of other tastes. But when under-extracted and many tastes are missing, saltiness reveals itself. Or rather, it is easier for people to catch. Therefore, the appearance of saltiness in coffee is also a signal of under-extraction.
Insufficient/no aftertaste: Aftertaste, sweet retronasal sensation, and other manifestations that come only after drinking coffee are phenomena emitted after the coffee substances remaining in the oral cavity dissolve. When under-extracted, the aromatic components contained in the substances are greatly reduced, so the aftertaste is not so obvious or prominent, and in severe cases, the aftertaste cannot be felt at all.
Weak, mediocre flavor: Under-extraction, simply understood, means not extracting enough, failing to fully extract the substances in the coffee, including flavor substances. And many flavor substances require different components to jointly constitute them, just like the principle of lemon tea. When under-extracted, a flavor may lack many constituting conditions, and the taste pulled out alone cannot be satisfying, so unclear, thin flavor is a manifestation of under-extraction.
Over-extraction Over-extraction is another extreme standing opposite to under-extraction. If under-extraction is not extracting enough, then over-extraction is extracting too much, extracting things that should not be extracted. So in the end, the coffee exhibits these conditions: Bitter! Too bitter: When we demand too much from the coffee grounds, the proportion of bitterness easily increases greatly. Because people are more sensitive to the perception of bitterness, when the proportion of bitterness in coffee is too high, it greatly suppresses the expressiveness of other tastes, making people feel as if the whole cup is bitter!
The above content is compiled by CoffeeHunters, a coffee news website.
