Is the fermentation of tea haraam?
Question

                I came across an old magazine, and noticed the following, which I will quote as it appears in the magazine, about tea and its benefits: “There is a difference between green and black tea in the way it is preserved and ‘fermented’ after being collected. Black tea, which is also known as Ceylon tea or English tea, is made from green tea, after the fresh leaves are picked and dried in a simple fashion, then they are soaked until they ferment.

 My question is: Is this process of fermenting tea regarded as haraam?.
Praise be to Allah.
    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.