How much caffeine is in 100ml of green tea?

As a rough guide for standard brewing, 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. Actual values vary with leaf quantity and brewing conditions.

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, which exceeds a cup of coffee.

How can I drink tea with less caffeine?

Genmaicha and hojicha are often lower in caffeine than sencha, though they still contain some. A caffeine-free drink like mugicha is an option if you want to avoid caffeine entirely. Cold-brewing or ice-brewing tea also tends to extract less caffeine than steeping with hot water.

What does theanine actually do?

Theanine is an amino acid especially characteristic of tea, and the source of its umami and sweetness. Research links it to a relaxed state, and studies have also examined how theanine combined with caffeine affects attention and mood.

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.

Green Tea Components｜Catechin, Caffeine & Theanine Explained

🇯🇵 日本語版はこちら

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

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.

Approximate Caffeine per 100ml of Beverage

Gyokuro

160mg

Coffee

60mg

Sencha / Hojicha

20mg

Genmaicha

10mg

Mugicha (Barley Tea)

0mg

*Approximate figures for standard brewing, based on Japan's Standard Tables of Food Composition. Actual values vary with leaf quantity, steeping time, water temperature, and product.

⚠️ If You're Watching Your Caffeine

If you'd like to avoid caffeine altogether, a caffeine-free drink like mugicha is your best option. Genmaicha and hojicha are often lower in caffeine than sencha, but they do still contain some. Cold-brew and ice-brew green tea also tend to extract less caffeine than brewing with hot water, though not down to zero. If you want to avoid caffeine entirely before bed, mugicha is the safer choice.
→ How to make cold-brew green tea (Japanese)

💊 If You Take Medication

Some medications can interact with tea's compounds. Always take medication with plain water, and check with your doctor or pharmacist 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? Theanine is thought to be part of that — an amino acid especially characteristic of tea, and also the source of its umami and sweetness.

How Theanine Works in the Body

There's research linking theanine to a relaxed state — for instance, Nobre et al. (2008) found that L-theanine intake increases alpha-wave activity in the brain. Studies have also looked at how theanine combined with caffeine affects attention and mood. The distinctive "calm yet clear-headed" feeling associated with green tea, quite different from coffee, may come from this balance of compounds.

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?: When leaves are exposed to sunlight, theanine accumulation is suppressed while catechin production is promoted. 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	Characteristics
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 tends to be higher in sun-grown sencha, and lower in shade-grown gyokuro and matcha, and roasted hojicha.
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	Tea contains fluoride; rinsing with tea is a long-standing traditional habit.
Potassium	A mineral involved in the body's fluid and electrolyte balance.
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 — though brewing cool doesn't remove the caffeine, so keep that in mind in the evening.

☕ 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 bring out more aroma when brewed at this higher end.

💡 A tip for morning versus evening: In the morning, go hot for a bold astringency and aroma. In the evening, if you're avoiding caffeine, a caffeine-free drink like mugicha is a good choice — or brew a small amount of green tea cool.
→ See our temperature and time chart by tea type

A Few Things to Keep in Mind

⚠️ If You're Watching Your Caffeine: Before bed, or during pregnancy or nursing, a caffeine-free drink like mugicha is a good choice if you'd rather avoid caffeine.

Sources and notes
· Publicly available food composition data on caffeine content
· Nobre, A.C., Rao, A., & Owen, G.N. (2008). L-theanine, a natural constituent in tea, and its effect on mental state. Asia Pacific Journal of Clinical Nutrition, 17(Suppl 1), 167-8.
· Further published research on theanine's relationship to relaxation, and on theanine-caffeine combinations
Note: This article draws on the public information and research cited above, compiled by the Minorien editorial team. Compound figures are approximate for standard brewing and vary by product and brewing conditions. Sources on catechin's interactions with iron and medication are listed on our catechin page.