Tea Blog

Among the more challenging aspects of writing about tea—and even of simply being a tea enthusiast—is navigating the many myths and inconsistencies surrounding tea terminology.

This issue of terminology is explored further in

this discussion of common spelling and naming inconsistencies in tea-related terms
,
which highlights how even basic definitions can vary.

One particularly common source of confusion is the distinction between fermentation and oxidation in tea processing.

While the term “fermentation” is often used to describe the process that produces black and oolong teas, the more accurate term in these cases is oxidation. For example,

black teas that are fully oxidized and develop their characteristic dark color and bold flavor

undergo complete oxidation, whereas oolong teas are only partially oxidized.

In the standard processing sequence for black tea—typically consisting of six stages—oxidation occurs after withering and rolling. During this phase, tea leaves are spread out in a controlled environment where chemical reactions transform compounds within the leaves.

These reactions produce substances such as thearubigins and theaflavins, which contribute to both the color and flavor profile of black tea.

In contrast,

oolong teas that are partially oxidized and vary widely in flavor depending on processing level

undergo oxidation for a shorter period. This results in a diverse range of styles, from light, green tea-like oolongs to darker varieties that approach black tea in character.

True fermentation does occur in tea production, but primarily in the processing of

puerh tea known for its microbial fermentation and aging characteristics
.
There are two main types: raw (sheng) puerh, which ferments naturally over time, and cooked (shou) puerh, in which fermentation is accelerated through controlled processing methods.

For a deeper technical perspective on these processes, see

this detailed explanation of oxidation and fermentation in tea manufacturing
,
which explores the chemical and biological mechanisms involved.

© Online Stores, Inc., and The English Tea Store Blog. Unauthorized use is prohibited. Excerpts allowed with proper credit.