Why is tea oxidized

It is imperative for the tea masters to have complete control over how much oxidation occurs, and through temperature of the oxygen rich air is how it is achieved. Oxidation occurs best when at a slightly warm temperature but can be stopped at a much hotter temperature.

When the leaf has reached the ideal oxidized level the producers will stop turn up the heat and stop this process, known as fixing, or killing green. Some of the most common fixing methods would be pan firing, steaming, or baking the leaf. Why does this matter? Oxidation is a crucial step in tea processing, it has a lot to do with the final outcome of the teas aroma and flavour. It can change the characteristics in the cup.

But this doesn't answer the fundamental question… What is oxidation? Oxidation in a nutshell Any dictionary will tell you that Oxidation is a chemical reaction. Where oxygen atoms lose electrons. When plants are damaged, cut, or crushed… Air gets in and enzymes rapidly oxidize.

The leaf is plucked from the bush. The more oxidized the more dark the tea will be. Is Oxidation the same as Fermentation in Tea? No, oxidation is not the same as fermentation in tea.

True fermentation is the chemical breakdown by microbes. Especially in regards to yeast. What are Fermented Teas? There are also some Japanese fermented teas. However most teas are not fermented. Oxidation is not Fermentation Why the confusion? When Tea was becoming popular in the west in the midth-century… When terminology was applied to the mysterious and little-understood tea. That termination still exists today. So while people will say fermentation in regards to tea: They typically mean Oxidation.

Oxidation in Tea Categories The enzymes in the leaf mix with oxygen to oxidize. Green tea is not oxidized. The vegetal and astringent notes of unoxidized tea like Green Tea … Convert into the rich, tannic, malty and fruity tastes of oxidized tea like Red tea.

Passive vs. Active Oxidization. But this is hardly efficient for Red tea. In which the enzymes are fully exhausted in the leaf. This is done to rupture more cells. And rendered inert. It's important to note though: Technically Green tea does have a negligible amount of oxidation. Because as soon as the leaf is picked the process starts.

Encouraging Oxidization in Tea As you've seen, Oxidization brings a lot of changing on to a tea leaf. In Wu Long Oolong , the amount of oxidization can range. Red Tea Oxidation Red tea has effectively had all of it's enzyme exhausted. Today, scientific research has helped us define the chemical processes that occur during the various steps of crafting , but the long history and guarded crafting traditions have led to some common misconceptions and confusing terminology.

The confluence of these two words is compounded by confusing translations of the names of tea categories. To clarify, understanding the distinction between oxidation and fermentation is essential. So what is the difference between the two, and how can we define them in the context of tea processing?

Oxidation is an enzymatic reaction that causes a tea leaf to turn brown after harvest. To be specific, this reaction occurs when the cell walls are broken, and polyphenol oxidase is exposed to oxygen in the atmosphere. This chemical reaction is the same process that occurs when an apple or avocado turns brown after being cut. To use the same apple analogy, this is the same as baking the apple, perhaps into a pie. Oxidation is the process that produces the color-coded categories we know in the west.

Put simply, green tea is roasted quickly to prevent oxidation, while black tea is allowed to oxidize fully, turning brown before roasting. During the process of oxidation, the leaves are carefully monitored, so that the reaction can be stopped at the desired level.

To be clear, this process is entirely a chemical reaction. It is caused by the proteins in the leaf reacting with the oxygen in the air. Left unchecked, oxidation will result in full deterioration of the leaf, just as a bruised apple will eventually rot.

Therefore, techniques developed to induce and control oxidation have been an integral part of tea crafting throughout history. One thing most definitions have in common, though, is that fermentation requires microbial activity. In tea, this is generally taken to mean any microbial activity, whether it occurs with or without oxygen present.

Most notable and widespread is pu-erh , which is made in Yunnan, in the south of China.