How is Tea Sensation Assessed in Coffee Flavor Evaluation? Causes of Obvious Astringency in Coffee

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In the coffee flavor wheel, we can hardly find any descriptions about tea... Even "black tea" is classified under floral notes.

But despite this, in the flavor descriptions of many coffee beans sold domestically, we often see descriptions of tea flavors ~ such as green tea, black tea, oolong tea... How are these tea flavors determined? Is astringency the same as tea sensation?

What is Tea Sensation?

Believe you have also experienced a slight rough feeling on your tongue when drinking tea (emphasis: very slight ~ just a faint astringency on the tongue surface), accompanied by a sweet sweet feeling. At this time, take a sip of clear water, and the water also tastes sweet ~

This sweet aftertaste is mainly because the tea contains tea polyphenols and glycosides. The main function of tea polyphenols is to stimulate salivary glands to secrete saliva, thus creating a moistening sensation.

Meanwhile, glycoside substances will attach to the oral cavity during the process of drinking tea. After a while of hydrolysis, glucose is produced, making you feel sweet - this is called sweet aftertaste. The more hydrolyzable tannins in tea (that is, the more energy substances retained), the stronger and more lasting the sweet aftertaste and salivation.

What's the Difference Between Astringency and the Rough Tongue Sensation During Salivation and Sweet Aftertaste?

Astringency belongs to oral tactile sensation ~ The appearance of "astringency" is how polyphenol compounds in food present themselves in the mouth, creating a rough feeling. Although astringency is unpleasant, we still need to divide it into two types: positive astringency and negative astringency.

Positive astringency can enrich the layers of coffee. For example, slight citrus peel astringency, clean acidity plus slight fruit peel astringency can make us think of eating the inner peel (the layer that wraps the pulp) when eating pomelo pulp. The sweet and sour taste with a slight bitterness is neither offensive nor has a sweet aftertaste.

Negative astringency is difficult to reverse. For example, if the coffee variety itself has too much chlorogenic acid, it will degrade into quinic acid during the roasting process. Quinic acid is a phenolic acid and non-volatile, so it cannot be smelled through the sense of smell, but it tastes bitter and has strong astringency.

Another example is incomplete dehydration during coffee bean roasting. The moisture in green beans will affect heat conduction, easily leading to the situation where the bean surface is cooked but the core is still under-roasted. Drinking it will give some grassy taste with a green, mouth-piercing feeling.

Positive astringency only causes slight roughness on the tongue surface, and this feeling will quickly dissipate accompanied by the sweet taste of aftertaste. Negative astringency, however, will leave a long-lasting dry/sour/bitter feeling on the tongue surface, and even after rinsing with clear water, you can still feel obvious roughness on the tongue surface.

Why Does Coffee Have Tea Sensation?

There is another reason for the salivation and sweet aftertaste when drinking tea: organic acids in tea (one of the main components of aroma). Organic acids stimulate salivary glands to secrete, thus producing the feeling of "salivation and sweet aftertaste." For example, when we eat fruits like green plums, bayberries, and plums, the mouth easily produces saliva.

And coffee itself has very rich organic acids ~ The excellent acidity of coffee is formed by the conversion of various organic acid substances in green coffee beans through roasting ~ So the amount of organic acid substances in coffee beans also determines the acidity performance of coffee.

Under normal circumstances, the lighter the roast degree, the more obvious the acidity, but not all acidity is positive. Planting altitude and soil fertility have positive effects on the formation of organic substances in coffee beans.

For example, Kenyan coffee beans grown at an altitude of 1600 meters, when lightly roasted, can exhibit bright, solid acidity. But if Brazilian coffee beans grown at an altitude of about 1000 meters are lightly roasted, they can only show hollow acidity and strong nutty flavors.

Usually only high-altitude grown coffee beans, when lightly roasted with suitable methods, will exhibit lively, bright acidity. When these acidity notes are accompanied by slight astringency and combined with certain aromas in the cup, people will associate them with the feeling of drinking tea, bringing salivation and sweet aftertaste ~ And this feeling is the tea sensation in coffee.

How Many Types of Tea Sensation Are There in Coffee?

Whether one can taste tea sensation in coffee depends on whether the coffee drinker is familiar with the aroma and taste of tea and the resulting salivation and sweet aftertaste. Most Chinese people have certain impressions and memories of the feelings brought by different tea types, so when everyone drinks coffee that brings slight roughness to the tongue surface, they will always associate it with a certain type of tea.

For example, when we taste green tea, green tea itself retains a large amount of tea polyphenols, so the mouth will have a rough feeling (slight astringency) and fresh aroma. At the same time, you will also feel the fishy smell of seaweed food, which is called umami (meaning delicious taste, a special taste brought by amino acids) ~

FrontStreet Coffee, when tasting washed Yirgacheffe coffee, often feels that the aftertaste of the coffee has the unique umami of green tea or the fresh aroma of green tea itself.

Another example is when tasting green tea (oolong, Tieguanyin, etc.), as it belongs to semi-fermented tea, the tea sensation is smooth, mellow and refreshing, with obvious sweet aftertaste and lasting fragrance ~

FrontStreet Coffee, when tasting washed Hacienda La Esmeralda Green Label coffee, feels obvious sweet aftertaste and a light feeling, just like drinking Tieguanyin tea, with both aroma and sweet aftertaste being very lasting.

Another, another, another example is when tasting black tea, as it belongs to fully fermented tea, the tea sensation is full and solid, with rich aroma, strong tea taste and obvious sweet aftertaste ~

FrontStreet Coffee, when tasting their own Yunnan sun-dried Typica coffee, feels that the aftertaste has solid sweet aftertaste, like the feeling of drinking black tea.

These different oral tactile sensations and flavors will make Chinese people think of different types of tea, so descriptions of tea flavor/tea aroma/tea sensation often appear in coffee beans purchased domestically.

Why Is There Only "Black Tea" Description on the Flavor Wheel?

Many flavor references in flavor theory come from North America ~ In foreign countries, there are rarely descriptions about tea in the flavor descriptions of specialty coffee beans, because they don't have much definition and concept of the aroma and salivation sweet aftertaste of different tea types. Therefore, even "black tea" is judged from the sense of smell and classified into the floral category.

Coffee beans sold domestically like to use tea sensation/tea aroma as flavor descriptions because Chinese people have an "innate" familiarity with tea sensation. It's also hoped that through the description of tea flavor, more people will gradually change their inherent impression that coffee only has burnt bitter taste, and be told that coffee can also be like tea, with excellent aroma, clean taste, and pleasant salivation and sweet aftertaste.

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