What happens after harvest?

Once tea leaves are picked, they begin to change.

Producers guide this change through a series of steps that may include:

• Withering
• Heating
• Rolling or shaping
• Oxidation
• Roasting or aging

Each decision influences aroma, texture and depth.

What is oxidation?

Oxidation happens when tea leaves are exposed to air.

It is similar to what happens when you cut or bite into an apple. The surface slowly turns brown. That change happens because oxygen reacts with compounds inside the fruit.

Tea leaves respond in a similar way.

When the leaves are rolled or gently bruised after harvest, oxygen interacts with their natural compounds. This changes the colour of the leaf and gradually shifts the flavour.

Less oxidation keeps the tea lighter and greener.

More oxidation deepens the colour and strengthens the flavour.

Levels of oxidation

Different tea styles are defined by how much oxidation occurs.

White Tea
Minimal processing. Very low oxidation.

Green Tea
Oxidation is halted early through heat.

Oolong Tea
Partially oxidised.

Black Tea
Fully oxidised.

Pu’er and Dark Teas
Undergo additional aging or post fermentation.

Other processing factors

Oxidation is only one variable.

Roasting can add warmth and depth.

Shaping can influence how a tea brews.

Aging can soften sharpness over time.

Processing is where craftsmanship becomes visible in the cup.

Why it matters

Understanding processing helps you anticipate flavour.

It explains why one tea tastes bright and grassy while another feels deep and malty, even though both come from the same plant.

It also makes brewing adjustments easier.

The leaf provides the foundation. Processing reveals its direction.

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