Does Tea Contain Chemicals?

What makes tea, tea? What is the chemistry makeup of tea and does tea actually contain chemicals? Let’s discuss this further with some commonly asked questions.

The Chemicals in Tea

What makes tea, tea?

Common Questions

Here are some commonly asked questions surrounding the magical makeup of tea.

What is Tea?

Tea is specific to the Camellia sinensis plant. The Camellia sinensis plant is an evergreen bush that is native to Asia. Nowadays, tea can be grown in many other places around the globe including Africa, North America and even New Zealand. The tea plant prefers a tropical or subtropical climate in close proximity to the equator, however, the plant can be grown almost anywhere, the leaves just may not be harvestable for a good cuppa.

What Climate do you Need to Grow Tea?

Tea leaves generally really love a balance of rain, sunshine and humidity for optimum flavour. Many tea plantations are found at high altitude in mountainous areas of Asia. Here the growing tea leaves benefit from the climate and produce wonderful tasting tea.

How Many Different Species of Tea Plant are There?

There are around 200 types of tea plant, these include: Camellia sinensis var. assamica, Camellia sinensis var. sinensis, Camellia sinensis var. japonica and Camellia sinensis var. cambodiensis. Only certain varieties of the tea plant can produce tea leaves suitable for a lovely cup of tea.

How is Tea Harvested and Processed?

There are many different types of tea that is harvested from the tea plant, these include; white tea, green tea, oolong tea, black tea and pu’erh tea. There are also rare teas such as yellow tea.

Each type of tea is harvested and processed in a unique way, not only specific to the type of tea but specific to many factors such as the grade of tea, the season that the tea is harvested and also the area that the tea is grown.

White tea is generally the least processed tea. The buds or shoots are harvested and allowed to gently dry. White tea is usually very delicate in taste and appearance, sometimes the leaves can still appear furry when closely inspected.

Green tea is the only type of tea that undergoes an additional type of process named ‘killing the green’. This process is what gives green tea its famous green leafy colour and wonderful levels of antioxidants. ‘Killing the green’ is what halts the oxidisation of the tea leaves.

Oolong tea falls somewhere between a green and a black tea. There are different types of green tea, some of which are lighter and more delicate similar to green tea and some of which are darker similar to black tea. This is all down to the level of oxidisation that the tea leaves undergo.

Black tea is the most popular tea consumed in Europe, commonly referred to in England as ‘builders brew’. Black tea is fully oxidised and is the darkest, richest and fullest bodied tea.

Pu’erh tea is a matured type of tea. Many experienced tea connoisseurs enjoy fermented pu’erh tea in formed cakes or bricks. A piece of the cake or brick is crumbled and brewed accordingly. This type of tea undergoes a microbial fermentation which continues to oxidise until the desired taste and texture is reached.

There are also herbal teas, however, these do not come from the Camellia sinensis plant and are tisanes or herbal infusions rather than actual teas.

Read More: Single Estate Teas


What is a Chemical?

Chemicals are present in almost everything. A chemical is a substance resulting from changes to atoms or molecules, known as a chemical process. There are both natural artificial chemicals.

How Does the Chemical Composition in Tea Change?

Chemical reactions happen in tea at many points in the growing and processing stage. Firstly, the photosynthesis stage creates a chemical reaction in the plant. Factors that affect photosynthesis are; sunlight, shade, temperature and carbon dioxide concentration. Some teas, such as matcha green tea, are shaded prior to harvest so that new shoots are grown with higher amounts of chlorophyll. This is what gives matcha green tea its vibrant green leafy colour.

Some teas such as Oriental Beauty Oolongs (Donfang meiren) are produced by encouraging leaf hopper insects to feast on the juices of the tea leaves. This starts the oxidisation process before the leaves are harvested which creates the unique sweetly honey taste and aroma.

After tea leaves are harvested, the leaves undergo withering and oxidisation. These drying processes allow the leaves to wilt and the cells to break down. All of these stages are what determines the overall chemical composition of the tea.

What are the Chemicals Found in Tea?

Caffeine is found naturally in many plants, including tea, and it works as a natural insect repellent to protect the growing plant. Caffeine is a drug/stimulant called trimethylxanthine and surprisingly, caffeine has a similar chemical make up as some illicit drugs and has the same biochemical mechanisms that can stimulate brain function.

Generally, the more oxidised the tea, the higher levels of caffeine present in the leaves. It is difficult to calculate the exact levels of caffeine found in tea as there are many factors such as amount of tea leaves used, steeping time and water temperature.

Read More: Caffeine in Tea vs Coffee

Tannins found in tea are what gives tea it’s dark colour and sometimes bitter taste. Tannins, also known as tannic acid are found in other naturally produced products such as beer and wine. Tannins are antioxidants found in tea and are a type of polyphenol. Darker teas that have been more oxidised will contain higher amounts of tannins in comparison to lighter teas. The longer that a cup of tea is brewed, the darker the colour and the more tannins that will be present. But too much steeping time may result in a bitter brew!

L-Theanine is possibly my most favourite chemical found in tea. L-Theanine is a type of amino acid that has antioxidant effects on the body. This wonderful amino acid is proven to help with stress and anxiety as it can aid in modulating brain function and help with calmness whist staying aware and focused. It is thought that L-Theanine can counter balance the negative effects of caffeine found in tea.

Read More: Is Tea Good at Reducing Anxiety?

Catechins are natural compounds found in tea. These are known as polyphenols or flavonoids. Epicatechin (EC) and epigallocatechin gallate (EGCG) are types of Catechins found in tea that can aid in removing free radicals from the body.

When tea is processed, the catechins (aka the antioxidants) are metabolised into polyphenols, known as flavonols. Different teas contain different types and different amounts of flavonols. For instance, black tea contains flavonols known as thearubigins and theaflavins.

There are about 28 minerals found in tea. These include fluorine, iodine, magnesium, potassium, selenium and zinc! All of which are super important to maintaining good health and wellbeing.

The chemistry of tea is quite complex and it’s no wonder that tea is such a magical drink enjoyed the world over!

What’s your favourite type of tea? Comment below!

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This blog is for information purposes only. It is not intended to treat, cure or diagnose any medical conditions. Always seek advice from your healthcare provider.