Astringency is a dry, fuzzy, or rough sensation on the palate that occurs when eating some foods or drinking some drinks. Astringency is distinct from sourness and bitterness, although it often occurs together with these flavors. Most tea is ;somewhat astringent, more so than a lot of common food and drink. The astringency of tea is caused mainly by polyphenols, which are antioxidants, including the catechins of green tea
Caffeine is a naturally-occurring stimulant, found in several plants. Caffeine is water soluble, and is extracted into the brewed cup when preparing tea. In most cases, tea has much less caffeine than coffee.
Although there is no official translation of the word "umami", some call it "savory taste": it leaves a mild and lasting pleasant brothy after taste and is recognized as one of the five basic tastes (together with sweetness, sourness, bitterness, and saltiness). It also induces salivation and a furriness sensation on the tongue, stimulating the throat, the roof and the back of the mouth.
The natural bitterness of green tea comes from the way it is made. Unlike black and oolong teas, green teas are made from the unfermented leaves of the tea plant, which keeps the antioxidants intact, but also gives them the bitter taste. This bitterness can be regulated with the water temperature : the higher the more bitter and vice-versa.
L-theanine (here referred to as theanine) is an amino acid that has a relaxing, but not sedating, effect. It is renowned for its ability to put you in the ideal state of calm attentiveness. It can sharpen focus, while reducing stress and enhancing overall well-being. Theanine can interact with caffeine, allowing a smaller dose of caffeine to have a stronger effect in terms of boosting concentration and alertness.
In Japanese, "sukkiri" refers to the refreshing feeling left by a drink or a food, or even simply the fact of taking a shower after a hot summer day. Your mind and body feel refresh. When it comes to green tea, this feeling is somewhat the opposite of umami, which is a "rich" taste, that leaves a sensation of furriness on the tongue. A "refreshing" tea is therefore a tea whose acidity, lightness and aroma remind you of a thirst-quenching drink.
A sweet-tasting tea is a very light tea that leaves a sensation of natural sweetness in the mouth.
Catechins are a type of polyphenol (EGCG) and are the main astringency component in green tea, long known as tannins. In order to release more catechins you will need higher brewing temperature at around 80 but this will also increase the astringency and bitterness of your tea because of the caffeine. Dont use such temperatures for Gyokuro.
Raw tea leaves contain little fragrance, but when harvested, enzymes work to disperse the individual tea leaf components and release their fragrance The fragrance of teas is developed through the heating process, where the amino acids and saccharides react to the heat to form the tea's wonderful and very delicate fragrance.