What tea for kombucha?

Various choices of Formosan teas in Natural Organic Products Show (ExCel London)
Growing in popularity; people in the Western World (USA, UK, Europe,...) are becoming more and more interested in learning how to make kombucha at home.
Tea is one of the most essential ingredients of the fermented tea, i.e., kombucha.
However, it is superficial that many people think that just using "culture" with the tea is the way to make "kombucha". This is not correct, nor is it healthy.
Making kombucha is a complicated task. It takes months for the "second" fermentation of the tea.
Why is it the "second"?
Because when a tea farm harvests and processes tea leaves at the plantation, different levels of the "first" fermentation develop into various kinds of tea. Green tea, for example, is not fermented at all at this stage. Thus, green tea "usually"[1] is recommended due to its high antioxidant levels (due to tea Polyphenols). However, microbial fermentation is the key factor responsible for the formation of sensory attributes and the chemical components of tea.
"Unlike green tea that have not undergone microbial fermentation, microbial fermented tea has special sensory characteristics, including bright tea infusion, unique aroma, sweet, and smooth taste with low levels of bitterness and astringency.... Furthermore, tea has been fermented by microorganisms that are attracting increasing attention because of its various health benefits, including protection against hypertension and cardiovascular diseases." (Hu, Shi and Ma, 2022)
Therefore, tea in the first fermentation at the tea plantation/ process factory determines the quality and benefits of the second fermentation in brewing kombucha.
Unfortunately, many "how to make kombucha courses" focus on the CULTURE, or scoby, rather than the TEA.
Tea matters!
Unfortunately, many people have been taught to use green tea to make kombucha, which makes no sense to me at all. As a tea expert, there are at least two elements set to fail if using standard green tea to make kombucha:
1. Green tea is ZERO fermentation: why use a non-fermentation tea to make the second fermentation?
2. Green tea contains very LITTLE tea microbial: how to make a good level of second fermentation without enough microbial in the tea?
Formosan Farms has been collaborating with Pure Kombucha in the UK since 2018. Pure Kombucha has been awarded as the most innovative healthy brand in England by 2021 Food & Drink Award. The most strength to support the best quality kombucha results from the best quality fermented teas (over 70% in the first fermentation), such as the most famous Red Jade (Taiwan No. 18, or Ruby Tea), Taiwan Native Mountain Tea (Wild Mountain Tea), Red Oolong(Dark Oolong, or Pearl Oolong),and Red Rhyme (Taiwan No.21). If the small producers are looking for extraordinary quality, the vintage teas are more recommended!
If you are making your own kombucha, or in the kombucha business, this is the secret behind success.

Note:
[1] The most research of green tea did not consider the plant varieties. Recently, Formosan Farms and academic scholars at Chung Shan Medical University found that Red Jade, or Taiwan No.18, which is a fully fermented red tea, was the highest antioxidant among all other popular green teas and oolong teas available in Taiwan.

References:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9378870/
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