What happens after coffee is swallowed in the cup

Aftertaste and sweetness are not the same thing. The finish is what remains in the mouth after coffee is swallowed: aroma, taste and mouthfeel left behind. Hui gan, the returning sweetness tasters praise, is one type of positive finish. It needs a base of bitterness or astringency and is perceived through contrast, so it cannot simply be equated with sweetness.

Finish is judged on quality and duration. Positive finishes show floral notes, fruity sweetness, tea-like or honeyed qualities, while earthy, rubbery or sawdust notes and drying, rough mouthfeels are negative. Good flavors that linger longer score better; a chocolate or cocoa note from a well-extracted espresso can stay in the mouth for around ten minutes. Roast level also shifts how the finish reads.

When tasting coffee, many people use "hui gan" (returning sweetness) to describe a delicious mouthfeel, but are hui gan and sweetness really the same thing? This article starts from the concept of finish to clarify the essential difference between hui gan and sweetness, and analyzes the mechanism and perception principles behind hui gan—it requires a foundation of bitterness or astringency and can only be perceived through taste contrast. At the same time, the article will also explore the differences in finish performance between dark-roasted and light-roasted coffees, and recommend several Front Street selected coffee beans for friends who prefer high sweetness, low acidity, and low bitterness, helping you find your ideal cup in everyday brewing.

"Hui gan sheng jin, ku jin gan lai" (returning sweetness and promoting saliva, sweetness after bitterness) is people's highest praise for a good cup of tea, and in coffee tasting, people also often use the term "hui gan," usually referring to coffee having a pleasing mouthfeel. So, what kind of taste experience is hui gan in coffee? And how is it different from coffee's sweetness?

After coffee is swallowed, the aroma, taste, and mouthfeel exhibited by the coffee substances remaining in the oral cavity are what we call the finish. Before swallowing, the coffee taste, aroma, and touch felt are categorized as flavor and mouthfeel performance; after swallowing, these characteristics exhibited are called the finish. You can simply understand this as a matter of time difference. In this way, when tasting coffee in the future, you can use this time period to judge which part belongs to flavor and mouthfeel and which part belongs to the finish.

The finish is usually divided into two types: positive and negative. Good coffee naturally has a positive finish, such as floral notes, fruity sweetness, tea-like notes, honeyed feel, and so on. Hui gan is one type of positive finish; negative finish performance is commonly seen in earthy, rubbery, sawdust-like tastes, as well as unpleasant mouthfeels such as dryness, roughness, and throat-catching.

Besides quality, when evaluating the finish we also look at how long it lasts. The longer a good flavor lingers, the better the finish performance. For example, after drinking an espresso with a good finish, the chocolate and cocoa aromas remaining in the mouth can last for ten minutes, while an espresso with a short finish, even if it has no negative mouthfeel after drinking, will still have its aroma completely disappear within seconds. High-quality espresso cannot be separated from good coffee beans. For home espresso making, the top choices are Front Street Classic Blend, Front Street Commercial Blend, Front Street Specialty Blend, and Front Street Dark Cocoa Blend.

Next, let us take a closer look at the expression of hui gan. It is a taste bud experience in which coffee enters the mouth with slight bitterness or sourness and astringency, then the sweetness gradually surpasses the bitter (sour) and astringent feeling, and finally ends with sweetness. The so-called "bitterness first, sweetness later" is the clear sweet breath that comes back after the bitterness dissipates in the mouth. For example, with the oil orange from Chaoshan, the first bite brings a stimulating sourness, with slight astringency on the tongue surface, and then the mouth begins to produce saliva while being filled with a clear sweet taste.

From this, it can be seen that hui gan here must be a taste expressed on the basis of a certain degree of bitterness or astringency. Unlike the sweetness directly felt when eating candy, it must go through "bitterness" and be set off by "bitterness" before it can be called "hui gan." However, it should be noted that the degree of bitterness and the intensity of hui gan are not necessarily connected. An over-extracted coffee may be very bitter, but it may not have hui gan.

When we evaluate dark-roasted coffee beans that mainly feature bitterness, hui gan is a very good indicator. Front Street Brazil Queen Estate Coffee is recommended. When tasting it, there is first an aroma of roasted peanuts and dark chocolate with bitterness, and then the bitterness begins to fade, accompanied by a sweet mouthfeel that continues for some time without weakening. This can be called a good hui gan.

Another one, Front Street PWN Golden Mandheling, uses medium-dark roasting and also belongs to the hui gan type of coffee. It has a rich caramel aroma. On the palate, there are special flavors of herbs, spices, and sandalwood. After drinking, the thick sweet taste remains lingering.

Today, many coffees adopt light roasting, highlighting floral notes and rich fruity acidity while also lacking a mellow, solid bitterness. The brewed coffee consists mostly of small-molecule substances, is strongly hydrophilic, and volatilizes easily. In addition, it contains abundant organic acids, which promote saliva secretion when entering the mouth, thereby accelerating the loss of flavor. This is also why, when drinking light-roasted coffee, the finish is often not as strong and lasting as that of dark-roasted coffee.

Because of this, compared with the term "hui gan," baristas tend to describe the finish of this type of floral and fruity coffee by combining its lingering aroma in the mouth and its sweet-and-sour aftertaste.

For a high-sweetness coffee with natural hui gan, Front Street Boquete Geisha is the top choice. Its finish will be described as the tea-like notes of Tieguanyin, the fruity acidity of sugar mandarin, and the sweet aroma of honey.

Finally, Front Street has noticed a phenomenon: some friends understand the sweetness obtained after drinking water following coffee as hui gan. In fact, this is an oral illusion brought by sensory contrast under the impact of bitterness. Because sweetness and bitterness are relative concepts, after tasting sucrose you will find that water is somewhat bitter, while after tasting bitter coffee you will feel that water is sweet. This phenomenon is a contrast effect. Similarly, hui gan can also be understood as an illusion of the mouth under the impact of bitterness.

The above content is compiled by CoffeeHunters, a coffee news website.