What is the difference between drying and withering tea leaves

The similarity between withering and drying

Many people may think that there is no difference between “withering” and “spreading”, because whether it is “withering” or “spreading”, fresh tea leaves need to be spread out on bamboo plaques, mats, baskets or curtains, adjusted to the appropriate thickness, so that they can change during the static process.

The purpose of both methods is to dissipate some of the moisture in fresh leaves, achieving different standards for tea softness and moisture content. But “withering” and “spreading” are names for different tea making processes, and their essence is very different.

spreading

1. The concept of spreading green

Spread the picked fresh leaves evenly in a cool and ventilated environment to release moisture and grassy air, allowing them to release moisture and naturally complete the greening process. The time for tea leaves to turn from crisp and hard to soft depends on factors such as season, climate, and the tenderness of the tea leaves.

The fresh leaves that have been laid green have reduced moisture content and become soft, which is beneficial for subsequent manual withering. Fresh leaves that are not spread out in a timely manner can lead to poor ventilation, and when squeezed or suffocated, they will heat up and turn red, affecting their quality. Due to their own fermentation process, red stems and leaves will appear, seriously affecting the quality of the raw materials. If the green is not spread or the green is killed before the green time is up, it will cause the pot to become burnt, resulting in a burnt taste and burnt pieces in the finished product

2. Purpose of spreading green

After withering, fresh leaves become softer and reduce their moisture content to a certain extent, which is more conducive to the subsequent withering process.

Evaporate some of the moisture from fresh leaves, reduce the tension of tea cells, soften the stems, increase the toughness of buds and leaves, and facilitate subsequent rolling and twisting processes. Numerous studies have shown that the optimal moisture content for fresh leaves during green tea processing is around 70%. The moisture content of fresh leaves is about 75%, which means that by spreading and drying, the moisture content can be reduced by 5 percentage points

withering

1. The concept of withering

Fresh leaves are spread under certain equipment and environmental conditions to evaporate water, reduce volume, and soften leaf quality. This enhances enzyme activity, causes changes in the contents, and promotes the formation of tea quality. There are physical dehydration processes as well as chemical changes in internal substances

2. Purpose of withering

One is to evaporate some of the water, reduce the tension of tea cells, make the leaf stems brittle and soft, increase the toughness of buds and leaves, and facilitate rolling into strips; The second is to form effective substances that are conducive to the quality of tea, and polyphenols are also oxidized to varying degrees. Normal and effective withering causes the green grass aroma of fresh leaves to fade and produce a refreshing fragrance, with a fruity or floral aroma. The resulting tea has a mellow taste without bitterness, laying the foundation for the specific qualities of tea color, aroma, and taste through material changes. The moisture content of withered leaves is generally lower than that of fresh leaves after drying, mostly ranging from 60% to 64%

The difference between the two

Drying is a more natural state of water loss.

Withering often involves the involvement of external forces, such as sunlight withering or withering in a withering trough, requiring careful control of temperature, humidity, ventilation, and other factors.

The moisture content of fresh leaves is around 75%

The moisture content for drying is around 70%.

The moisture content of withering is around 60% to 64%.

The drying process is more common in green tea, yellow tea, and black tea

The withering process is more common in white tea, black tea, and oolong tea

Because in the tea making process, whether to use “spreading green” or “withering” determines the direction of the tea leaves we make. The direction of the fresh leaves after being spread forms a crossroads, roughly: spreading green tea: killing green tea – heading towards green tea, yellow tea, black tea. Withering: Continuing to wither – towards green tea, white tea, and black tea.

The condition for judging the difference between the two is whether the fresh leaves only lose water in a single physical aspect, and the chemical changes have not yet begun. Compared to spreading green, withering involves both physical changes and chemical reactions (chemical reactions formed by the transformation of substances in fresh leaves). The fresh leaves that have been spread green to the point are stretched, vibrant, glossy, and moderately soft and hard. Withering leaves rub against each other without making any sound, lose their luster, turn dark green, and won’t bounce quickly when pinched.