The composition of tea is the foundation of tea science. Only by understanding these components can we understand the reasons why tea presents a certain taste or aroma, and where the difference between good and bad tea quality lies. Therefore, in the process of brewing tea, we can flexibly control the strengths and avoid weaknesses, and create the best flavor of a tea.
Ordinary tea lovers do not need to understand the physical and chemical properties and mechanisms of action of tea ingredients like scientists do. They only need to understand the following aspects:
The fresh leaves of tea trees, abbreviated as tea tree fresh leaves, contain about 75% moisture and the remaining 25% dry matter. Because different processing techniques can cause differences in tea composition, the material composition of fresh leaves is more statistically representative.
Three characteristic components of tea
Among the more than ten components rich in tea, the top three are tea polyphenols (mainly catechins), alkaloids (mainly caffeine), and amino acids (mainly theanine), which are the three characteristic components of tea. Why are they called characteristic components
1.these components are unique to tea and are rare or scarce in other plants, while tea leaves have high levels of them.
(Tea polyphenols, also known as tea tannins, are a group of polyphenolic substances present in tea plants. Although caffeine is called caffeine, it is more abundant in tea than in coffee. Theanine is a unique amino acid found in tea and is extremely rare in other plants.)
2. it must have water solubility, which allows it to dissolve into water after being brewed with water in order to be absorbed by humans
3. The third is that drinking it has physiological reactions, and different ingredients have different physiological reactions.
Tea polyphenols, caffeine, and theanine are the most important components of tea and the basis for the unique quality of tea.
Other important components of tea
In addition, pigments, aromatic substances, and sugars in tea have a significant impact on the color, aroma, and taste of tea leaves. It is particularly worth mentioning that the content of aromatic substances in tea is extremely low, accounting for only 0.005% -0.03%, but it contains a wide variety of types, and the aroma is particularly amazing.
Many aromatic substances smell fragrant at low concentrations, but smelly at high concentrations. Therefore, it makes sense that tea leaves have such a low content of aromatic substances but still smell so fragrant.
Careful observation may reveal that the protein content in tea is as high as 20% -30%, why is it rarely mentioned?
In chemistry, it is mentioned that proteins are stable large molecular compounds composed of multiple amino acids tightly linked together. In plant leaves, proteins are important substances that make up cells, but during processing, the vast majority of proteins undergo heat induced coagulation and denaturation, with very few able to dissolve into tea water. On the contrary, free amino acids are different and can be directly dissolved in water, which has a direct impact on the taste and aroma of tea. Therefore, when it comes to the effective substances in tea, amino acids are often mentioned and protein is rarely mentioned.
Why does tea go from bitter to sweet
Many people may find that tea has a slightly astringent taste when first consumed. Some people will use this to conclude that this type of tea is not good tea. In fact, the bitterness of tea is not always bad. Whether it is a good tea depends on whether it can regain its sweetness after bitterness. Professor Ye Naixing from the Department of Tea Studies introduced that “the taste of tea soup is determined by the comprehensive reaction of people’s taste senses to the flavor substances in tea leaves. Different types of tea leaves exhibit different flavors due to the different types, contents, and ratios of flavor components.
The main flavor substances in tea soup
In fact, the taste of tea is a harmonious combination of multiple flavors. The main flavor substances in tea are tea polyphenols and their oxidized products (theaflavins, thearubigins, etc.), amino acids, caffeine, soluble sugars, organic acids, water-soluble proteins, and aromatic oils. The different types, contents, and ratios of these substances in different types of tea can profoundly affect the taste of the tea soup. The four main flavors of tea soup and their corresponding flavor components are as follows:
Taste components in tea soup
Polyphenolic substances are highly present in fresh tea leaves, generally ranging from 18% to 36% (dry weight). Polyphenolic compounds mostly have bitter and astringent tastes, and due to their high content, they account for the largest proportion in water extracts, making them the main substances determining the taste of tea soup.
Caffeine has a bitter taste. In tea soup, caffeine binds with a large amount of catechins, theaflavins, thearubigins, etc. to form complexes, preventing the complexation with proteins. This changes the taste characteristics, which is beneficial for the formation of fresh and mellow tea soup taste and reduces bitterness.
Amino acids are the main substances that make up the fresh and refreshing taste of tea. There are abundant types of amino acids in tea, and the flavor properties of each amino acid are different. Theanine, which accounts for 50% -70% of the total amino acid content in tea, has a particularly high freshness and refreshing taste, which can alleviate the bitter taste of tea and enhance its sweetness. Glutamic acid, glycine, proline, and other substances coexist with theanine in tea soup, which has a synergistic effect on the presentation of the umami taste of theanine.
The sugars that present a sweet taste in tea soup are mainly soluble sugars such as monosaccharides and disaccharides contained in tea leaves. They have a certain masking and coordinating effect on the bitterness and astringency of tea. The higher the content of these sugars, the sweeter and less bitter the tea taste. Some amino acids, catechins, and thearubigins also contribute to the sweetness of tea soup.