How much caffeine is in 100ml of green tea?

Sencha and hojicha contain roughly 20mg, while gyokuro stands out at roughly 160mg. For reference, coffee is about 60mg, genmaicha about 10mg, and mugicha (barley tea) is caffeine-free.

Does green tea or coffee have more caffeine?

Standard sencha or hojicha (about 20mg per 100ml) has less caffeine than coffee (about 60mg). Gyokuro is the exception, at roughly 160mg — nearly triple a cup of coffee.

How can I drink tea with less caffeine?

Genmaicha, hojicha, and mugicha are naturally low in caffeine. Cold-brewing or ice-brewing tea also extracts significantly less caffeine than steeping with hot water.

What does theanine actually do?

Theanine is an amino acid unique to tea, and the source of its umami and sweetness. Studies show it brings the brain into a gently relaxed state roughly 40–50 minutes after drinking, and it also softens caffeine's stimulating effect.

Does catechin break down with heat?

Quite the opposite — catechins dissolve out more readily as water temperature rises. That's why tea brewed with boiling water tastes more astringent, while tea brewed cooler comes out mellower.

Why does hojicha have less caffeine?

The high-heat roasting process that gives hojicha its toasty character also breaks down some of its caffeine, leaving it lower than the sencha or bancha it's made from — roughly 20mg per 100ml, on par with standard sencha.

How Much Caffeine Is in Green Tea?

Chemical structures of theanine and catechin overlaid on an image of tea leaves

There's a real reason a cup of tea can leave you feeling either relaxed or refreshed. The flavor and character of green tea comes down mainly to three compounds: catechins, caffeine, and theanine.

The balance between these three creates tea's astringency, umami, and bitterness — and that balance shifts depending on the brewing temperature. As a Shizuoka tea specialty shop that works with tea every single day, we're breaking it all down in plain terms.

🍵

Catechins

Astringency / bitterness

Tea's "defensive" compound. The hotter the water, the more that dissolves out.

⚡

Caffeine

Bitterness

Sharpens focus. Paired with theanine, it acts more gently than it does alone.

😌

Theanine

Umami / sweetness

An amino acid unique to tea. Behind that "settled" feeling. Dissolves readily at low temperatures.

Infographic illustrating tea's three main compounds — catechins, caffeine, and theanine — and how flavor changes across low (up to 70°C), medium (70–90°C), and high (90–100°C) brewing temperatures

Catechins: The Source of Tea's Astringency

🍃 What Are Catechins?

That astringent bite you notice in a cup of tea comes from catechins — a type of polyphenol that green tea contains in abundance.

Catechins share a key trait: the hotter the water, the more of them dissolve out. That's why tea brewed with boiling water tastes more astringent, while tea brewed with cooler water comes out mellower.

💡 Why isn't gyokuro astringent?: Gyokuro and matcha are grown under shade before harvest, which keeps catechin levels low. Hojicha, meanwhile, loses catechins during its high-heat roasting process — both end up with a milder, less astringent character as a result.

→ Learn more about catechins (Japanese)

Caffeine: The Energy Behind Tea's Bitterness

Caffeine sharpens focus and wards off drowsiness. What sets tea's caffeine apart is that, paired with theanine, it acts more gently than the caffeine in coffee.

Caffeine per 100ml of Beverage

Gyokuro

160mg

Coffee

60mg

Sencha / Hojicha

20mg

Genmaicha

10mg

Mugicha (Barley Tea)

0mg

⚠️ If You're Watching Your Caffeine

If you're pregnant, nursing, or brewing a cup before bed, genmaicha, hojicha, or mugicha are good choices. Cold-brew and ice-brew green tea also cut caffeine significantly.
→ How to make cold-brew green tea

💊 If You Take Medication

Some medications (including certain blood pressure medications) can interact with tea's compounds. Always take medication with plain water, and check with your doctor if you have concerns.

Theanine: The Source of That "Settled" Feeling

Ever noticed how a cup of tea can leave you feeling calm and settled? That's theanine at work — an amino acid found only in tea, and also the source of its umami and sweetness.

How Theanine Works in the Body

Studies show that roughly 40–50 minutes after drinking tea, the brain settles into a gently relaxed state. Because theanine also softens caffeine's stimulating effect, green tea tends to produce a distinctive "calm yet clear-headed" feeling — quite different from coffee.

That's why a cup between tasks at work or study can feel like such a natural reset.

💡 Why is gyokuro so rich in umami?: Sunlight converts theanine into catechins (astringency). Growing gyokuro and matcha under netting before harvest — blocking that sunlight — keeps theanine levels high, producing their signature deep umami.

Infographic explaining gyokuro's shade cultivation: black netting blocks sunlight to suppress catechins (bitterness) and keep theanine (umami) levels high, with workers hand-picking tea beneath the shade

Blocking sunlight to protect umami

Vitamins & Minerals: Why Green Tea Is Called "Nutrient-Rich"

Beyond its three main compounds, green tea contains a range of other nutrients — making your everyday cup a surprisingly rich drink.

Compound	What does it do for you?
Vitamin C	Normally heat-sensitive, but green tea's catechins help protect it — so you still get vitamin C even from a hot cup. It's richest in sun-grown sencha; shade-grown gyokuro and matcha, and roasted hojicha, contain very little.
Vitamin E & Beta-Carotene	These don't dissolve into hot water, so a regular steeped cup misses out. Drinking the whole leaf, as with matcha or powdered tea, gets you the full amount.
Fluoride	Known for strengthening teeth — rinsing with tea is a long-standing traditional habit.
Potassium	A mineral that helps the body process excess sodium.
Saponins	The compound behind the light foam that forms when tea is poured.
Dietary Fiber	Hard to get from a steeped cup alone, but easily obtained by consuming the whole leaf via matcha or powdered tea.

💡 Matcha and powdered tea deliver the whole leaf: Tea brewed in a teapot only gives you the compounds that dissolve into the water. Matcha and powdered tea, by contrast, have you consume the leaf itself — capturing vitamin E, dietary fiber, and other compounds that hot water alone leaves behind.
→ Browse our powdered tea (Japanese)

How Temperature Changes What You're Drinking

Even with the same leaves, the water temperature determines which compounds dissolve out — and that changes the entire character of the cup.

🌡️ Low (up to 70°C)

Theanine (umami, sweetness) dominates, keeping astringency in check. Mellow and sweet. Best for gyokuro and premium sencha.

☕ Medium (70–90°C)

A balance of umami and astringency. Most everyday teas — sencha, fukamushicha, kukicha, konacha — fall in this range.

🔥 High (90–100°C)

More catechins and caffeine dissolve out, for a brisk astringency and pronounced aroma. Hojicha and genmaicha should always be brewed at this temperature.

💡 A tip for morning versus evening: In the morning, go hot for a bold astringency and aroma. In the evening or before bed, try gyokuro or premium sencha brewed cool.
→ See our temperature and time chart by tea type

A Few Things to Keep in Mind

⚠️ If you're anemic: Catechins can bind readily with non-heme iron. Consider avoiding tea for 30 minutes before and after iron-rich meals, or opt for a caffeine-free drink like mugicha instead.

⚠️ Regarding supplements: Drinking ordinary tea poses no issue, but taking concentrated catechin supplements in excess can affect the body. Stick to moderate amounts.

⚠️ If you're taking medication: Some medications can interact with tea's compounds. Always take medication with plain water.

Close-up of green tea leaves with an overlaid illustration of catechin's molecular structure

About Catechins (Japanese)

A closer look at the types and their traits

A young Japanese woman in casual clothing pouring tea from a teapot in a modern kitchen

How to Brew Delicious Japanese Tea

A quick-reference chart of temperature and time

A package of benifuuki tea alongside a brewed cup

What Is Benifuuki? (Japanese)

Rich in methylated catechins

Close-up of vivid dark green fukamushicha being poured into a white cup

Shop Fukamushicha (Japanese)

Our signature product