茶是發酵還是氧化? Is tea Fermentation or Oxidation?

茶是發酵還是氧化? Is tea Fermentation or Oxidation?

茶葉以製作方式不同來區分為紅茶、黃茶、綠茶、黑茶、白茶、青茶等六大種類，此六大種類我們通常也說個個發酵程度不同。

There are six categories of tea by different tea making process, such as black tea, yellow tea, green tea, dark tea, white tea and blue tea. We usually say they have different fermentation. 

但事實上茶葉真有發酵作用嗎?

However, is there fermentation on tea leaves?

茶葉應是氧化作用而不是發酵作用。

Tea leaves only have oxidation not fermentation.

由於茶葉始自東方，中文稱為發酵，因此英文也翻成fermentation這個字，但事實上，應該是氧化，英文應是oxidation。

且國外的文獻，也質疑茶葉中發酵fermentation 的用法，並更正為氧化oxidation的用法。

The tea originated from Asia, in Chinese is fermentation. In English is also fermentation. It’s a translation error. The right word is oxidation.  

首先，何謂發酵作用?

First, what is fermentation?

發酵作用是一種微生物將糖轉換成酸、氣體或酒精的一種特別型態。

我們讓東西發酵用來製作一些化學產品或副產品。發酵作用有以下特徵。

Fermentation is a specific type of microbial metabolism that converts sugar into acids, gases or alcohol. We ferment things with the goal of producing a specific chemical product or some byproducts. The process of fermentation has the following characteristics.

我們主要說的發酵作用是它產出的副產品。有一些如酒類的發酵及乳酸的發酵(使用來從牛奶製作優格)等..。

We typically describe fermentation in terms of its major excreted byproducts. Few of the example of fermentation are alcohol fermentation, lactic acid fermentation (used to produce yogurt from milk) etc. 

發酵作用可能是在有氧或無氧的狀況。

Fermentation can happen with or without oxygen.

發酵作用需要催化有機體如細菌或酵母。

Fermentation needs catalytic organisms like bacteria or yeast. 

以上發酵作用的定義，只有對於普洱茶的後發酵有所適用，對於其它茶種並無一處適用於茶葉所稱的發酵作用。

The definition of fermentation only suitable for Pu’re tea. However, there is nothing for other category of tea.

其次，何謂茶葉氧化作用?

Second, what is the oxidation of the tea leaf?

氧化的基本原理，任何植物被採摘下來便開始枯萎和氧化(如常見植物葉片變成褐色。)

控制氧化的良窳於製茶流程上，攸關茶湯色澤與風味的呈現。

The principle of oxidation is when the leaves were plucked they start to fade and oxidize.( The leaves begin to turn brown.)

When making tea, controlling the oxidation influences the color of tea and most of tea’s gustatory properties.

茶葉氧化如何進行?

How does oxidation work?

茶葉細胞裡有一種酵素，稱作氧化酶。當茶葉細胞構造因自然受損或是人為揉捻，造成細胞破裂時，氧化酶便會被釋出，啟動氧化流程。

There is an enzyme in the tea leaf known as oxidase. When the structure of the tea leaf’s cellular is damaged by natural power or deliberately by rolling, the oxidase will be released and begin the oxidizing action. 

它會對空氣中的氧起反應，氧化酶會出現氧化流程並改變茶葉中的茶多酚成分；然而兒茶素經過代謝後會形成兩類分子:一為茶紅素；另一為茶黃素，它們將決定茶色變化。

The enzyme will react with the oxygen in the air. The oxidase will oxidize and convert the polyphenol of the leaf. Then metabolize the catechins into two other groups of molecules, the thearubigins and the theaflavins which are responsible for the liquor’ color.  

完全氧化茶100% oxidized : 

紅茶 Black tea

部分氧化茶 semioxidized: 

黃茶 Yellow tea

白茶 White tea

青茶Blue tea: 
文山包種茶      Wenshen Paochong tea

高山茶     High-mountain Oolong tea    

凍頂烏龍茶 Dongding Oolong tea

鐵觀音茶   Tieh-Kuan-Yin tea

白毫烏龍茶 White-tip Oolong tea

無氧化茶0 % oxidized: 

綠茶 Green tea