Oolong tea: caffeine, brewing and taste

A cup of oolong tea (237 ml) usually has 4–29 mg of caffeine, about 17 mg on average (18% of a cup of filter coffee).

At a glance

Type	Partly oxidised tea
Caffeine per cup	4–29 mg
mg / 100 ml	7.2
Cups to reach 400 mg a day	more than 20
Water temperature	85–95 °C
Steeping time	2–3 min

How it is made

Oxidation is stopped part-way: oolong is oxidised from about 5% up to 70%, so it can taste closer to green or closer to black.

Taste

A wide range, from light and floral to richer and roasted, depending on oxidation and roasting.

How to brew

About 85–95 °C for roughly 2–3 minutes; the leaves can often be infused several times.

For caffeine figures we assume 2 g of dry tea per cup (237 ml).

Brewing timer →

Steeping time and caffeine

Longer steeping releases more caffeine. Calculated for 2 g of tea per cup.

Time	Caffeine per cup
2 min	3–19 mg
3 min	3–25 mg
4 min	4–27 mg
5 min	4–29 mg

When to drink it

Caffeine's half-life is usually 3–7 hours (we use about 5), so after 5 hours roughly half a cup's caffeine can still be in the body. About 100 mg before bed may affect sleep (EUFIC).

Last cup tool →

Frequently asked questions

How much caffeine is in oolong tea?

A cup of oolong tea (237 ml) usually has 4–29 mg of caffeine, about 17 mg on average (18% of a cup of filter coffee).

How do you brew oolong?

About 85–95 °C for roughly 2–3 minutes; the leaves can often be infused several times. For caffeine figures we assume 2 g of dry tea per cup (237 ml).

Is oolong tea good in the evening?

A cup has about 17 mg of caffeine. After 5 hours roughly half can remain, so sensitive people may prefer earlier in the day. Some people are more sensitive to caffeine than others.