Caffeine in milk tea versus coffee: a sense of the numbers

A common misconception: milk tea is a "light" drink, fine in the evening, while coffee is the thing that keeps you awake.

But tea contains caffeine too — and milk tea is made from strongly brewed tea, so some cups carry more than a small coffee.

The relative order

There's no fixed figure per cup, because too much varies. But the ordering helps:

• Strong Vietnamese filter coffee — highest among the familiar drinks.
• Machine coffee (espresso, americano) — depends on shots; one shot is usually below a strong filter.
• Black-tea milk tea — in the range of a small coffee, and some cups above it.
• Green-tea or oolong milk tea — usually below black tea, but by no means caffeine-free.
• Genuine herbal infusions — chamomile, lemongrass-ginger, mint — no caffeine.

The point to remember: the milk tea range and the coffee range overlap. You can't assume milk tea is the lighter option.

Why milk tea is harder to predict

A black coffee's caffeine depends mainly on how much coffee went in. Milk tea has more variables:

• Type of tea. Black is usually higher than green or oolong.
• How strongly it's brewed. Milk tea needs very strong tea so the flavour isn't swamped by milk — far stronger than tea drunk on its own.
• Cup size. Milk tea cups are typically much larger than coffee cups. Same concentration at double the volume is double the total.
• Whether an extra strong-tea shot is added, which varies by shop and by drink.

Cup size is the most overlooked factor. A small filter coffee against a large milk tea is a comparison of two very different volumes.

Why milk tea feels lighter

The interesting part: tea contains L-theanine, which coffee doesn't. It's thought to soften the jittery edge caffeine produces.

The result is a smoother alertness without the jolt — but the caffeine still goes in. Feeling comfortable doesn't mean a low dose.

Add sweetness and milk making it easy to drink, and people get through a large cup faster without noticing.

Thinking about the evening

Caffeine stays in the body for a long time — a meaningful fraction remains many hours later. A cup at 5pm is still working at bedtime.

Individual thresholds vary far more than people assume:

• Fast metabolisers — coffee in the evening and still sleep.
• Slow metabolisers — one afternoon milk tea is enough for a restless night.
• Daily habit builds tolerance, so regular drinkers feel less than occasional ones.

A practical approach: if you sleep badly, move your last caffeinated drink a few hours earlier for a week and see whether it changes. That's how you learn your own threshold, more accurately than any general figure.

Who should pay more attention

• Pregnancy and breastfeeding — limits are recommended, and the specific figure is a question for a doctor.
• Heart conditions, anxiety, or acid reflux.
• Children and teenagers — milk tea is a drink young people favour, and few think about the caffeine in it.
• Anyone on medication — some medicines interact with caffeine.

This is general information; it gives no recommended limits and doesn't replace medical advice.

Evening drinks that won't affect sleep

• Genuine herbal infusions — chamomile, lemongrass-ginger, mint. Read carefully: "jasmine tea" is green tea scented with flowers and still contains caffeine.
• Soy or other plant milk — no caffeine, and some protein.
• Juice.
• Milk-based drinks without tea — some shops offer a milk base instead of a tea base.

Five shops, all open 24 hours: 38 Le Thi Rieng, 15B Nguyen Thi Minh Khai, 2B Tran Hung Dao, 148B De Tham (District 1) and 210 Bui Van Ba (District 7). Call 0923.183.183.

Quick answers

Does milk tea contain caffeine?

Yes. It's made from very strongly brewed tea so the flavour survives the milk, so some cups sit in the range of a small coffee and some go above it. The two ranges overlap.

Why is milk tea harder to predict than coffee?

More variables: tea type, brew strength, cup size, and whether an extra strong-tea shot is added. Cup size is the most overlooked — milk tea cups are usually much larger.

Why does tea feel smoother than coffee?

Because of L-theanine, which coffee lacks and which is thought to soften the jittery edge. But the caffeine still goes in — a comfortable feeling doesn't mean a low dose.

What time affects sleep?

It depends on the person, and the differences are large. Caffeine lingers for many hours, so a 5pm cup is still working at bedtime for a slow metaboliser.

How do I find my own threshold?

Move your last caffeinated drink a few hours earlier for a week and see whether sleep changes. More accurate than any general figure.

What can I drink in the evening instead?

Genuine herbal infusions such as chamomile, lemongrass-ginger or mint; soy milk; juice. Note that "jasmine tea" is scented green tea and still contains caffeine.