Green tea is a type of tea made from the leaves of the Camellia sinensis plant, that have undergone minimal oxidation during production. Its leaves are picked and then quickly heated to stop the oxidation process.

This is to help retain the tea's natural aroma, resulting in a more delicate and fresh tea.

Green tea originated in China, where it is known as Lǜ Chá (Chinese: 綠茶, "green tea"). Today, it is widely consumed and harvested all around East and Southeast Asia, including China, Japan, India, and Indonesia, as well as other parts of the world.

It is known for its subtle flavour and numerous health benefits. In contrast to the strong and robust flavour of black tea, green tea has a delicate and refreshing taste. 

One of the unique characteristics of green tea is its shorter shelf life compared to black tea. Green tea usually loses its flavour within a year, so it is essential to store it properly and consume it while still fresh.

Varieties and names

Here are some of the most popular green tea varieties, their names and where they are produced:

Blends

Here are some of the most popular green teas and what makes them distinctive:

Manufacture

The production of green tea requires careful handling to preserve its delicate flavour. After the leaves are harvested, they are quickly steamed or pan-fried to stop oxidation and preserve the natural colour and flavour of the leaves.

The next step is to roll and shape the leaves, which can be done either by hand or by machine. This process helps to release the natural oils and aroma. They are then dried, which can be done using various methods, including hot air drying, sun drying, or baking.

Finally, the dried leaves are sorted into different grades based on their size and quality. Whole leaves are the highest grade, followed by broken leaves, fannings, and dust. The leaves are then packaged for sale.

There are two main manufacturing methods for green tea:

1. Fresh tea leaf → steaming → rolling → shaping → drying → sorting and packaging

2. Fresh tea leaf → pan-frying or oven-roasting → rolling → shaping → drying → sorting and packaging

Green tea is produced using different methods depending on the region where it is grown. The two main green tea producing regions are Japan and China, each with their own unique methods.

In Japan, green tea usually made by steaming the freshly harvested leaves to prevent oxidation, which helps to preserve its natural green colour and delicate flavour. The steaming process is brief, usually lasting for about 30 seconds, and the tea leaves are then rolled into thin needle-like shapes before being dried. This method is known as the "Sencha" method and is commonly used to produce high-quality Japanese green teas such as Gyokuro, Sencha, and Bancha.

In China, green tea is traditionally made by pan-frying or oven-roasting the tea leaves in large metal vats, reminiscent of woks. The heat from the pan-frying process stops the oxidation process, similar to the Japanese steaming method, and produces a range of flavors, from mild to nutty and smoky. This method is known as the "kill-green" process and is commonly used to produce famous Chinese green teas such as Longjing (Dragon Well) and Biluochun.

These manufacturing methods are not exclusive to Japan and China, as other countries such as Vietnam and Bangladesh also use them.

Green tea is best consumed fresh, within six months up to to a year of being harvested.

Tea grading

Green tea is usually graded on a similar scale of quality as other true teas, although the terminology used may differ slightly. The highest quality green teas are typically classified as "fine" or "specialty" teas, while lower grades may be labeled as "premium", "select", or simply "green tea". 

The highest quality green teas are usually made from whole leaves. Whole-leaf green teas are prized for their delicate flavour and aroma, and are often packaged in loose-leaf form. The most valuable loose leaf teas, usually contain leaf tips.

Broken leaves often end up in medium-grade loose leaf teas or sometimes in tea bags. Fannings, smaller tea particles that are left over from the production, are commonly used in tea bags. Their small size allows for a quick and complete diffusion of the tea into the water.

Dusts, even smaller left-over particles of green tea, often end up in bags as well, but may produce a bitter flavour if brewed too long. Some stronger bagged green teas often contain more tea dust to help speed up the brewing process. 

Overall, the quality of green tea can vary widely depending on the grade and processing methods used.

Brewing

Green tea should be brewed at a lower temperature than black tea, usually around  185-195°F (85-90°C). Using water that is too hot can burn the leaves and make the tea taste bitter. To make a good cup of green tea, use about 2 grams of loose tea leaves per 8 ounces (237 ml) of water.

The steeping time varies depending on the type of tea used. Some types of green tea, like sencha or dragonwell, should be steeped for 2-3 minutes, while others, like gyokuro or matcha, should only be steeped for 30 seconds to 1 minute. Over-steeping green tea can also result in a bitter taste.

After steeping, the tea should be strained to remove the leaves and stop the brewing process.

Caffeine content

One of the most well-known active components in green tea is caffeine, a natural stimulant also found in coffee. The amount of caffeine in green tea is lower than coffee, but may still provide a mild boost in energy and mental alertness.

On average, a cup of green tea contains between 30-50 mg of caffeine. But the caffeine content can vary depending on factors such as the type of green tea, brewing time and water temperature. 

How to distinguish green tea from other teas?

Green tea is distinguished from other teas by its low oxidation level and light, vegetal, and grassy flavour profile.

Nutritional content

Green tea contains various nutrients that can have some potential health benefits:

It is a rich source of antioxidants and other components, such as:

• Catechins

• EGCG

• Quercetin

• Phenolic acids

• Rutin

According to research, these antioxidants have some anti-inflammatory, anti-viral, imporvement of cognitive function, cardioprotective and anti-carcinogenic effects. (1)

In addition, green tea also contains the following amino acids (2):

• L-theanine

• Tyrosine

• Tryptophan

• Threonine

• Glutamic acid

• Serine

• Glycine

• Valine

• Leucine

• Aspartic acid

• Lysine

• Arginine

Green tea also contains vitamins and minerals, including vitamin C, vitamin B2, B3, vitamin E, and magnesium. It is also a source of phosphorus (2).

However, it is important to note that the amount of these nutrients can vary depending on factors such as the quality of the tea leaves and the brewing method. Additionally, green tea should not be relied upon as a primary source of these nutrients and a balanced and varied diet is necessary for overall health and wellbeing.