Tea to drink more, will always perceive some different tea, recently Xiao Understand received a question from a tea friend who just entered the circle: Recently drinking tea found that some tea smells very fragrant, but it is not so fragrant to drink, why?
If you think about it, this situation is indeed encountered when drinking tea, especially when drinking two or more teas, and the contrast is even more obvious.
Some teas smell the aroma straight through the Tianling Gai, but they don't have such a strong aroma when they drink, and some are even a little bitter, what is going on?
1
In fact, this is normal, the so-called smell of tea, this "smell" and "taste" are two systems.
Because the aroma is mainly perceived by us through the way of smell, and the tea soup in the entrance is the feeling conveyed by the taste, the tea color depends on seeing, the tea aroma depends on smell, and the tea taste depends on drinking.
The strength of the aroma of tea mainly depends on the degree of release of aromatic substances in tea.
When some teas are brewed, the aromatic substances that can be integrated into the tea soup are limited, and most of the aromatic substances are immediately released when they encounter high temperatures.
If you want to experience the aroma of this tea, you will smell more fragrant than you can drink. Moreover, different ways of smelling incense can also make people feel the different charm of tea fragrance (such as hot smell, cold smell, etc.).
From the release of aromatic substances, we know that the incense that is integrated into the tea soup and the incense that is not integrated are two camps, and some teas are smelling and drinking incense, which is the opposite of what we said above, that is, there are more aromatic substances integrated into the tea soup.
When we usually drink tea, the aroma of tea is usually divided into two kinds, one is "face incense" and the other is "falling water fragrance".
"Noodle incense" as the name suggests is that there is a taste on the noodles, but there is no inside, that is, we say that there is incense and no soup, and the aroma only flows on the surface; and "falling water incense" is also fragrant when smelling and drinking.
The reasons for these two situations are more complicated, but mainly the impact of the production process, and there is also a certain relationship with the raw materials.
The various aromatic substances in the tea have their own aroma characteristics, and the large number of fresh leaves is cis-green leaf alcohol, which has a strong grassy atmosphere.
After making green tea, it is mainly composed of indole, ionone compounds, benzyl alcohol, agarsol, hexenol and pyrazine compounds; after making black tea, it is mainly composed of agarmisol and its oxides, hexenol, methyl salicylate, hexacid, etc., and the aromatic substances in the tea leaves.
In addition to the aromatic substances introduced above, certain amino acids and their transformants, products of amino acids and catechin o-quinones have a certain tea aroma.
The boiling points of these aromatic substances are very different, the low ones are only a few tens of degrees to 100 ° C, and the high ones are more than 200 ° C.
For example, phyanosol, which accounts for 60% of the aromatic substances of fresh leaves, has a strong green odor, but because the boiling point of corporeal alcohol is only 157 °C, most of it is volatile and lost when it is killed at high temperature.
The aromatic substances with high boiling point, such as agarwood alcohol (i.e., linalool), geraniol, phenethyl alcohol, jasmonate, geranimate, etc. are retained more, so that the tea leaves form a unique fragrance, floral fragrance and fruity fragrance and so on.
Because the boiling point varies greatly, some low boiling point aroma substances are lost when they encounter hot water brewing, while some high boiling point substances are retained in the tea soup.
However, if there is a reason such as improper process or storage, it is possible that the aromatic substances that should exist in the tea soup are destroyed or cannot be formed, so that the taster cannot perceive the "soup contains incense" sensoryly.
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Understand the reason why tea has a fragrance and no soup, some tea friends still have great doubts about the production of tea aroma, so what factors affect the aroma of tea? Next, let's take a closer look at the aroma in tea!
01 tea tree varieties
The basic factor in the formation of tea aroma is the biosynthesis of aromatic substances in the body of the tea plant.
Aromatic alcohols and terpene alcohol compounds that play an important role in the aroma of tea are found in the fresh leaves of the tea plant as precursors to the aroma. These substances continuously release aromas that form a free state during processing.
The varieties of tea plants are closely related to the types, proportions and content of these aroma precursors. Therefore, tea leaves made from the fresh leaves of different types of tea plants have great differences in aroma style.
The different varieties of tea plants will also make the tea aroma type and aroma composition obviously different.
02 Processing method
The processing method also has a great influence on the aroma of tea, mainly manifested in:
(1) The release of the free aroma components of the aroma precursor in fresh leaves after enzymatic digestion (this is also the most important aspect).
(2) Some compounds in fresh leaves produce aromatic substances (such as amino acids, carotenoids, catechin polyphenols, etc.) after oxidation and degradation.
(3) Adsorption of exogenous aromatic substances by tea leaves.
Some researchers have pointed out when expounding the mechanism of aroma formation in black tea processing that withering is the foundation for the formation of black tea aroma, kneading and fermentation are the key to the formation of black tea aroma, and drying is an important process for the formation of black tea aroma.
There are also studies on the four drying methods of sun drying, drying, frying drying, infrared drying and high and low temperature as the conditions for experiments, and the results found that the drying method and temperature are different, and the tea aroma is also different.
The sun-dried tea has a mild entrance, but the aftertaste is astringent and the sun is heavy;
The dried fresh and mellow is still strong, and the chestnut aroma is sweet and full;
The taste of stir-fried dried is still strong and bitter, with chestnut aroma;
The infrared dry taste is still mellow and sweet, and the chestnut flavor is sweet.
High temperature dry tea, the taste is more fresh, the fragrance is fuller and sweeter;
Low temperature dry tea, slightly bitter taste, slightly low aroma.
These studies have also confirmed that the impact of processing on the aroma of tea is also very significant.
In addition, the tea leaves in processing adsorb external aroma substances, which will also make the tea have a unique aroma.
For example, smoked tea has a smoked drying process during processing, so that the tea leaves have a pleasant snuff aroma; jasmine, grapefruit and tea leaves are used to form jasmine tea, grapefruit flower tea and so on.
03 Ecological environment
Most of the tea areas south of the Yangtze River in China have four distinct seasons, and there are spring, summer and autumn tea. In general, spring tea is the best quality, followed by autumn tea, and summer tea is the worst quality. This aspect is also reflected in the aroma quality.
The amino acid content, which is closely related to the aroma of tea, has a significant negative correlation with the temperature level. As the temperature rises, the amino acid content in the tea leaves decreases and the aroma decreases.
In a certain temperature range, when the temperature is low, it is conducive to the synthesis of proteins, amino acids and other compounds. When the temperature is too high, the rate of amino acid decomposition is accelerated and the accumulation is reduced.
Of course, the effect of temperature on the metabolism of substances in the tea plant is not only amino acids, but also the impact on other substances is also quite obvious.
For example, pentenol and vinyl alcohol with a clear fragrance form more when the temperature is low, so the content of spring tea is higher than that of summer tea, which makes the spring tea set have a better tender aroma and mellow taste.
04 Other factors
There are many factors that affect the aroma of tea, and they are very complex.
In addition to the above several major reasons, there are also meteorological reasons such as the length of sunlight, humidity, precipitation; the impact of various processes in the processing process; and the role of packaging materials, storage conditions and time on the preservation of tea aroma, etc., which will have a great impact on the aroma of tea.