How to Identify Under-Extracted Pour-Over Coffee? What Happens with Over-Extraction and Perfect Extraction

Understanding Coffee Extraction: How Flavor Evolves Through Different Stages

When it comes to coffee extraction, do you know how coffee flavors differ at various extraction stages? FrontStreet Coffee often mentions how coffee flavors are extracted in sequence - first fruity acidity, followed by sweet nutty flavors, and finally the rich taste of bitter chocolate. When over-extracted, the result becomes bitter and astringent.

A complete cup of coffee that fully presents its inherent flavor characteristics is considered good coffee. However, sometimes during the brewing process, imperfect flavors may emerge - excessive sourness and bitterness, or an unpleasant, astringent taste. How can these undesirable flavors be avoided, and what causes such results? Next, FrontStreet Coffee will explain under-extraction and over-extraction.

First, it's necessary to understand what coffee extraction is. Extraction is the process where hot water passes through coffee grounds, dissolving and carrying out substances from the grounds. Through this extraction process, hot water transforms into a deep brown coffee liquid; flavors and aromas present themselves in different profiles depending on the coffee's growing background and extraction parameters.

So what representative coffee flavors do under-extraction, over-extraction, and ideal extraction each have to help drinkers identify the extraction state of their cup?

Under Extracted Coffee

Definition: Although hot water passes through the coffee grounds, due to insufficient dissolution, many substances remain in the grounds, resulting in not enough coffee compounds in the coffee liquid.

Flavor: Easily perceived sharp sourness, lack of sweetness, strange salty taste, and an aftertaste that is too short with no memorable finish.

Sharp Sourness: This type of sourness is rather negative, and the tongue's taste receptors typically strongly resist it at first. Sometimes it presents as an overly stimulating, extremely raw sharp sensation. It's worth noting that this differs from Acidity - acidity can be considered a flavor characteristic and is described more positively. Acidity generally doesn't cause physiological rejection and sometimes can bring refreshing, bright sensations.

Lack of Sweetness: The sweet aftertaste of coffee in the mouth leaves many drinkers with an endless回味. However, under-extracted coffee is overall thin and prone to creating a sense of emptiness. The main reason is that too many substances remain in the coffee grounds. After the initial stage (fruity acidity) is extracted, there's no continuation to bring out the sweet and mellow bitter flavors, resulting in under-extraction that makes the sharp sourness more prominent.

Strange Salty Taste: The four basic tastes - sour, sweet, bitter, and salty - coexist in coffee. When under-extracted, because only the sharp sourness has been extracted, while sweetness and bitterness have not yet been dissolved and released, this creates an imbalance among the four tastes. The单一 sharp sourness enhances the prominence of saltiness, making drinkers perceive a salty taste!

Short Aftertaste: Delicious food or good drinks always leave a satisfying, lingering sensation after consumption. Coffee is no different. Ideally extracted coffee's aftertaste can continue for quite some time. However, under-extracted coffee lacks good flavors and cannot bring satisfaction or surprise, let alone possess a memorable aftertaste.

Over Extracted Coffee

Definition: Hot water passes through the coffee grounds and dissolves too many substances, causing the soluble compounds in the coffee liquid to exceed balance.

Flavor: Easily perceived bitterness, dryness, and a hollow feeling without the soul of coffee.

Bitterness: Ideal extraction combines fruity acidity, sweetness, and bitterness. Since bitterness is the last flavor to be extracted, if over-extraction occurs, it will intensify the bitter sensation, causing excessive bitterness that overpowers other flavors. At the same time, it can also cause issues like excessive caffeine.

Dryness: Polyphenols are commonly found in plants, seeds, and tree bark, and coffee itself contains these substances. When coffee is over-extracted and then combines with proteins in saliva, it intensifies the dry sensation, causing uncomfortable feelings of grittiness and dryness in the mouth and teeth that persist for some time.

Hollow Feeling: Ideally extracted flavors allow drinkers to immerse themselves in the wonderful sensations that coffee brings. Over-extracted coffee lacks smooth, sweet flavors, with bitterness and dryness being the dominant notes. It can be said to cover and erase the perfect substances in coffee, making it impossible to taste coffee's unique soul.

Ideally Extracted Coffee

Definition: Hot water passes through the coffee grounds and dissolves just the right amount of substances, allowing the coffee compounds in the liquid to achieve perfect balance.

Flavor: Evenly presents refreshing fruity acidity, sweet nutty flavors, and the rich texture of bitter chocolate. The flavor is sweet and mature, clear and transparent, with balanced sour, sweet, bitter, and salty notes, and a long aftertaste that leaves one wanting more!

Sweet and Mature: Like fruit, which has rich acidity when first eaten, then reveals mature sweetness when chewed, coffee is similar. You can taste refreshing acidity and also sweet, mature flavors. Even with a slight bitter finish in the aftertaste, it can still return to sweetness.

Clear and Transparent: Only when coffee reaches the state of ideal extraction can drinkers have the extra mental energy to observe and feel the special flavors and advantages of the coffee. Imagine coffee in a state of under-extraction or over-extraction - the drinker's senses have been overwhelmed by unpleasant, intense sensations. Even if the coffee itself is of high quality, it's difficult to express its wonderful taste!

Balanced Sour, Sweet, Bitter, and Salty: Bright acidity, mellow sweetness, rich bitterness, and saltiness that pulls together each other's balance - four flavors coexist in a delicate, rich, and intoxicating way, redefining the perfect balance state of coffee tasting!

Long Aftertaste: Ideal extraction doesn't exhaust the senses due to extreme flavors. On the contrary, it not only leaves people reminiscing, but the lingering aftertaste is intoxicating!

Important Notice :

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FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

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