How is tea processed

Click the photo to the left for a more information. Passive Oxidation. This is a natural oxidation lacking an outside stimulus, such as the greening of copper or the rusting of metal. This process is excruciatingly slow in comparison to active oxidation. In regards to tea, the moment the leaf is plucked, the oxidase oxidative enzymes are activated, resulting in passive oxidation.

This method of oxidation continues throughout withering until it is halted by the enzyme kill stage, where the tea leaves are briefly flashed with heat. Controlled Oxidation. Controlled oxidation is where the conditions for oxidation have been manipulated by raising room temperature, humidity, and physically breaking the leaf epidermis. The degree of oxidation can be measured in various parameters. The exact time of drying varies depending on the water content of the leaves prior to drying.

For example, Taiwanese-styled oolong tea requires only minutes of drying while Indian black teas require up to minutes. Traditionally, these teas would ferment as they picked up microorganisms from exposure on the Silk Road.

In modern times, however the tea is stored in dark, humid rooms, conditions which are conducive to microbiological activity and oxidation. Researchers and tea growers continually experiment with new bacterial inoculations to create new pu-erh flavors. Jeng, and Y. A final Thoughts on the matter. The possibilities for tea processing are infinite and changing all the time. Tea has been around for thousands of years and the methods of altering its makeup and use are constantly evolving.

Some more foot notes to think about:. Avoiding microbiological activity. The utmost care is taken by tea processors to avoid any microbiological activity, which is a polite way of saying rotting or contamination. Tea growers and processors do, however, take extra precautions to avoid the loss of a harvest. In harvesting stages, tea pickers only select healthy and clean leaves. If any leaves happen to show signs of fungal growth, they are removed from the tree immediately.

Throughout every step of processing, tea leaves are arranged in thin layers and continually turned to allow for adequate exposure to air and inspection. This is why the technique of heaping is more difficult than it may initially sound: if the leaves are not periodically turned, bacteria could potentially grow.

The enzyme kill and drying stages are also essential to prevent any bacterial growth. Hybridization and stage treatments. As mentioned previously, there are multiple steps to each stage of processing. In the case of Japanese green tea, where withering is skipped, the tea will be dried times throughout processing. In other cases, some teas undergo a drying treatment in which their leaves are baked, allowed to rest, and then baked rested again for several treatments.

This was very helpful! I am hoping thins coming year to start growing and making my own tea and I have been very worried about the process and how everything is done.

I am still slightly worried that I will mess up something but I am planning on going to a local tea shop and asking them questions and doing some more research online. Nice presentation marred by many errors in process understanding perhaps the most glaring being that black and oolong tea has enzyme kill after withering. Stay Social. Get in touch. Tea Processing Apr, Processing Steps Harvesting Tea harvesting is a delicate process that is difficult to do quickly for fear of damaging the tea leaves.

Enzyme Kill - Reduction of enzyme activity The goal of the enzyme kill stage is to halt oxidative enzyme activity from the previous stages of tea processing. In a fully oxidized tea, amino acids and lipids break down completely, turning the leaves blackish-brown. The flavors in such a tea are more brisk and imposing. Rolling involves shaping the processed leaves into a tight form.

During the rolling action, essential oils and sap tend to ooze out of the leaves, intensifying the taste further. The more tightly rolled the leaves, the longer they will retain their freshness. In order to keep the tea moisture-free, they are dried at various stages of production. To dry the leaves they are fired or roasted at a low temperature for a controlled period of time, typically inside an industrial scale oven. If the leaves are dried too quickly, the tea can turn abrasive and taste harsh.

Some teas are subjected to aging and fermentation to make them more palatable. Some types of Chinese Pu-erh, for example, are aged and fermented for years, much like wine.

Classification of teas From one tea plant, it is possible to derive six types of tea: green tea , yellow tea, white tea , oolong tea , black tea and post-fermented tea. Tea processing techniques Between two and seven procedures are involved in the processing of fresh tea leaves; the addition or exclusion of any of these stages results in a different type of tea.

Withering Withering refers to the wilting of fresh green tea leaves. Oxidation A temperature-controlled oxidation floor at a tea processing unit Oxidation results in the browning of the leaves and intensification of their flavor compounds.

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