The subtle relationship between the degree of withering of tea leaves and the aroma of black tea

1、Withering refers to the process in which fresh leaves, under certain environmental conditions, uniformly lose the right amount of water, so that the cellular tension decreases, the leaves become soft from brittle and hard, and at the same time trigger a series of physical and chemical changes. This process is like starting a marvelous aroma metamorphosis journey for the tea leaves.

2、After the fresh leaves are picked, they contain a variety of aroma precursor substances, such as terpenes, alcohols, aldehydes and esters. These substances undergo complex transformations and reactions during the subsequent processing, resulting in the formation of black tea’s unique aroma. The withering process is the prelude to this chemical reaction, which creates the conditions for the transformation of the aroma precursor substances.

1.Light wilting (short time wilting)

When the withering time is short, the fresh leaves lose less water and the cellular activity is relatively high. At this time, the enzyme activity in the tea leaves is subject to limited stimulation, and the transformation of the aroma precursor substances is relatively slow. In this case, the black tea made tends to have more grassy gas, because part of the low boiling point of the green leaf alcohol and other substances have not been fully volatilized or transformed.

В същото време, due to the insufficient formation of aroma substances, the aroma of tea appears to be thin and lacks layers and complexity. For example, some rushed black tea production that shortens the withering time may result in a finished tea with a weak aroma, making it difficult to leave a deep impression.

2.Moderate wilting (moderate time wilting)

With the prolongation of withering time, when moderate withering is reached, the fresh leaves lose water moderately, and the enzyme activity in the cells is fully activated. Under the action of enzymes, the aroma precursor substances begin to be transformed in large quantities. For example, terpenes are gradually converted into compounds with floral characteristics, making the tea leaves emit a fresh floral aroma;

В същото време, the content of some alcohols increases, giving the tea a sweet and mellow aroma. At this time, the aroma of the tea leaves becomes rich and coordinated, with both fresh floral aroma and light sweet aroma, with distinct layers and long flavor. This is also the ideal withering state pursued by high-quality black tea, which can maximize the aroma potential of the tea itself.

3.Heavy wilting (prolonged wilting)

If the withering time is too long, the fresh leaves lose too much water, the cellular activity decreases and the enzyme activity is inhibited. Although some of the aroma precursor substances have been transformed, excessive withering may lead to volatilization loss of some aroma substances.

В допълнение, prolonged withering may also trigger excessive oxidation of the tea leaves and produce undesirable odors. For example, the tea leaves may have a stuffy and burnt odor, which seriously affects the quality and aroma of the tea leaves. Следователно, in actual production, it is necessary to strictly control the withering time to avoid the negative effects of excessive withering.

1.withering

Under the low temperature environment, the withering process is relatively slow and the enzyme activity is inhibited to some extent. In this case, the transformation of aroma precursor substances is more gentle, which is conducive to retaining some of the original aroma components in the tea leaves. The aroma of the black tea made is quiet and elegant, with more natural flavor, such as grass, tender flavor, and so on.

However, the low-temperature withering time is long, if not properly controlled, it is easy to cause the tea to be infected with microorganisms, affecting the quality of tea.

2.high temperature withering

High temperatures can accelerate the withering process, causing fresh leaves to lose water rapidly and enzyme activity to be strongly stimulated in a short period of time. This will promote the rapid transformation of aroma precursor substances and the formation of more high boiling point aroma substances.

Следователно, the black tea made by high temperature withering has a strong aroma, with obvious ripe and fruity flavor. However, high temperature is also easy to cause some aroma components in the tea to evaporate too quickly, and at the same time, if the temperature is too high or the time is too long, it may also make the tea produce burnt or roasted aroma, which hides the fresh aroma of the tea itself.

3.thermophilic atrophy

In order to take into account the advantages of low-temperature withering and high-temperature withering, some advanced black tea production process adopts the method of variable temperature withering. That is, in the early stage of withering, a lower temperature is used to make the tea leaves lose water slowly, so as to maintain better cellular activity and original aroma.

As withering proceeds, the temperature is gradually increased to accelerate the transformation and formation of aroma precursors, making the aroma of tea leaves richer and fuller. This way of temperature withering can effectively control the formation and development of aroma and improve the quality of black tea.

In the process of black tea production, tea makers need to flexibly adjust the withering time and temperature according to the variety of tea, origin, season and other factors, in order to achieve the optimal degree of withering, so that the aroma precursors in the tea are fully transformed and released, and ultimately form a high quality black tea with strong aroma, rich layers and unique flavor.

Only by understanding and mastering the subtle relationship between the degree of withering and the aroma of black tea, can we brew a cup of mesmerizing tea in the art of black tea production.