Is the fermentation of tea haraam?

The fermentation of tea that is mentioned in this article is
not the same as the fermentation that happens to grapes, dates etc in order
to make them intoxicants. Rather what is meant by fermentation here is
oxidization, i.e., exposing the tea to oxygen for three hours, according to
the experts.  

With green tea, the leaves are treated with steam after
picking, then they are dried immediately, and not exposed to any
oxidization, rather they are preserved with the same properties as are found
in fresh tea. 

But in the case of black tea, the leaves are separated after
collection and are sorted into fine layers on a net made of wire or
sackcloth in order to get rid of excess water, then the leaves are crumbled
and sifted, then subjected to an oxidization process, by exposing the fresh
leaves to oxygen for three hours, until the tea loses its green colour and
becomes dark coloured, after which it becomes black tea.  

If this oxidization is done only partially, we get tea that
is partially fermented, between green and black. This is called tannin and
it combines the qualities of both black and green tea. 

See: Mawsoo’ah al-A’shaab al-Tibbiyyah by the
pharmacist Dr Ahmad Muhammad ‘Awf; Qaamoos al-Ghidha’ wa’l-Tadaawi
bi’l-Nabaat by Ahmad Qudaamah, published by Daar al-Nafaa’is;
al-Ghidha’ la al-Dawa’ by Dr. Sabri al-Qabbaani, published by Dar
al-‘Ilm li’l-Malaayeen. All of these books are arranged in alphabetical
order. 

This is what we have been able to find out about expert
opinions on this matter. Thus it is clear that the process of fermenting
tealeaves is not haraam, rather fermenting them means exposing them to
oxygen, and we do no know of any scholar who says that this is haraam. 

And Allaah knows best.