Gourmet Tea
A Symphony of Taste and Aroma

Gourmet tea has an exquisite blend of taste and aroma. What is the chemistry behind it?

Gourmet tea is like a symphony of taste.

When you drink it, a variety of different flavors mingle on your tongue, blending together like individual instruments in an orchestra.

There are the natural flavors that arise from the tea leaves: sweetness, bitterness, astringency, unami, acidity and aromatic fragrances.

Then there are the artificial flavors that arise from the tea processes and surrounding environment.

(Admittedly, it is sometimes impossible to separate the natural from artificial.)

Tea is a complex agricultural product that defies all logical classification. If you a tea lover, then you want to understand the chemistry of taste.

This is the ONLY way to tell if you are drinking a high quality gourmet tea that look good, taste good, and feel good.

Are you ready?


The most important characteristic of tea is its astringency.

For a tea beginner, the lack of astringency and bitterness is what constitutes a fine cup of tea.

Another word for astringent is tannic. It feels dry in your mouth and gives you a contracting sensation, a bit like when you are eating grape skins.

Why is astringency important? Because it is what catechins taste like.

Health Benefits

Green tea can contain up to 30% to 40% catechins by dry weight. Powerful antioxidants are present in abundance in green tea, they account of most of its health benefits.

Fine gourmet tea is about balance. Having too many catechins can reduce quality because they can render a green tea undrinkable.

Leaf Age

The amount of catechins reduces with leaf age.

In China, the first or second leaf is often known as the one-bud-and-two-leaves. I sometimes call them young tea buds. They have more catechins compared to mature leaves.

However, these tea buds taste and feel better because they contain more theanine, as I will explain later.

This is my Number 1 rule of buying gourmet tea - always go for the tea buds.


Spring harvested leaves contain the least catechins and most theanine.

As the season progress, catechin content increases and peaks at summer, then reduces in autumn and winter.

What this means is that spring harvest is the highest quality and tastes the least astringent.

Summer harvest is lowest quality and tastes the most astringent.

Water Temperature

Catechins dissolve in water at temperature over 80 degrees Celsius. So if you want your tea to taste less astringent, use lower water temperature.


The bitterness of gourmet tea comes from it caffeine content.

The level of caffeine content tends to follow that of catechins.

Tea buds contain more caffeine than mature leaves. Summer crops have the highest level of caffeine.

Similarly, for spring harvested tea buds, which are considered to be the highest quality, the presence of theanine means the tea tastes sweet and full-bodied, rather than bitter.

The principle of balance comes into play again: Never consider caffeine in isolation.

Caffeine dissolves in water at temperature over 80 degrees Celsius. So if you want your tea to taste less bitter, use lower water temperature.

Water Temperature

Caffeine dissolves in water at temperature over 80 degrees Celsius. So if you want your tea to taste less bitter, use lower water temperature.

Tongue Location

The flat back of the tongue is most sensitive to bitterness, whereas the tip is most sensitive to sweetness.

A way to distract yourself if your tea tastes bitter?


It is hard to find a single word to describe the taste of theanine. It has been described as sweet, fresh, unami, full body flavors, brothy - you name it!

Theanine belongs to a class of chemical compound known as amino acids. It makes up more than 60% of amino acids.

Its chemical structure is similar to glutamine - which has a refined, rich and sweet flavor. Other types of amino acids present are glutamine, asparagine, arginine and serine.

Theanine is what makes gourmet tea such a special beverage. Not only does it taste good, it also makes you feel good.

It reduces your blood pressure and causes your brain to produce more alpha waves, leading to a calm, relaxed and yet energized state of mind.

It is naturally decaffeinating. If drinking coffee turns you into a twitchy wreck, you may want to switch to green tea.

The art of making gourmet tea - especially green tea - is all about increasing theanine content.

As alluded to earlier, there is more theanine in tea buds and less in mature leaves.

There is more theanine in the spring crop (after a long winter rest) and less in the summer crop (when temperature is high and leaves grow quickly).


When exposed to light, theanine can convert into catechins.

This is why some quality teas are grown using a technique called shading: Japanese tea farmers grow gyokuro tea in shades to maximize theanine content.

The use of shading is said to drain so much energy out of tea plants that harvests only take place once a year.

(Similarly, all high grade Chinese green teas only harvest once a year in spring - volume production is not compatible with quality.)

Water Temperature

Theanine dissolves in water at temperatures over 50 degrees Celsius.

Hence brewing at low temperature can make green tea taste better, especially if your gourmet tea contains too much catechins or caffeine.


The fragrance of gourmet tea helps people to relax. It makes tea work its wonder as an aromatherapy.

All of the olfactory receptor neurons that make up your sense of smell are concentrated in a small, postage-stamp size area at the top of the nose. The only way to get molecules up is through vapors given off by a liquid.

This is the reason why hot tea often "tastes" better.

Green Tea

But if you are a green tea drinker, don't expect too much.

Green tea contains a minute quantity of aromatic oils: 0.005%.

Raw tea leaves contain very little fragrances, but when harvested, tea enzymes work to disperse individual leaf components to release their fragrances.

With green tea, the oxidation process is brought to a stop soon after the harvest. The fragrances have little time to develop.

If you want to experience a once-in-a-lifetime green tea fragrance, then I will suggest HQ's Dragon Well tea King Grade. It comes with a hefty price tag though :(

Vitamin U

Vitamin U is a distinctive flavor found in high grade green tea such as gyokuro and sencha. It is often known as a “green laver aroma”.

It is another name for a chemical called S-methylmethionine.

Isolated in the 1950's from raw cabbage juice by Dr. Garnett Cheney, it was the compound responsible for cabbage juice's apparent ability to help people with peptic ulcers.


This is why oxidized teas are more aromatic than green tea.

Oxidation mainly happens through the withering process, which helps to form aroma.

The application of heat helps to combine the amino acids and saccharides to form aroma.

A semi-oxidized oolong tea such as an Iron Goddess has the highest level of aroma.

As the level of oxidization increases, the level of aroma reduces. However, the aroma increases in complexity.

A black tea is fully oxidized and contains more than 300 fragrances.

Such fragrances range from the muscat aroma of Darjeeling to the sweet rosy or fruity aroma of a black tea.

For a high grade gourmet tea, this process requires much skill and experience from the tea maker to get it exactly right.


Aroma can also be artificially enhanced through pan-roasting and oven-roasting.

These tend to be the low frequency aromas.

For green tea, the lower grades are often roasted more to impart this flavor.

Examples are the Japanese Hojicha and the Chinese Dragon Well.

(In the case of Dragon Well, the lower the grades, the longer the leaves are roasted.)

For tea lovers who like strong taste and who can't taste unami (estimated to be 1 in 5 of the population), a roasted green tea can seem heavenly.

Oolong tea and Chinese black tea are often oven-roasted to enrich the body. The process also improves durability of the tea.


This involves mixing tea leaves with flowers (such as jasmine), imparting the scent of flowers to the tea.

Gassiness and Fishiness

Chinese green tea is processed by pan-roasting and/or ovening, while Japanese green tea is steamed.

The flavor of Japanese green tea is different from Chinese green tea - when not done well, it can come across as grassy or fishy.


When catechins react with air and light, they oxidize and form theaflavins and thearubigins.

These compounds have a range of colors, from orange to a rich red. They help create the deep, rich colors and distinctive flavors of oolong tea and black tea.

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Ito-en website. "All About Green Tea." http://www.itoen.co.jp/eng/index.html.

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