How do I stop tea going bitter?

The three causes of bitter tea — time, temperature and squeezing — and the fix for each.

Difficulty: beginner
Time: 5 min
Read: 2 min

Short answer

Take the bag or leaves out when the time is up, use cooler water for green and white tea, and never squeeze the bag. Tea keeps extracting for as long as the leaf is in the water, which is why a cup that started fine tastes harsh by the time it is cool enough to drink.

Bitterness in tea is tannin, and tannin extracts steadily with time and faster at higher temperatures. Almost every bitter cup is the result of leaving the leaf in too long, using water that is too hot for the type, or squeezing concentrated tannin out of the bag.

What you'll need

Timer
Variable-temperature kettle (optional)
Infuser basket (optional)

Step by step

Time the brew and remove the leaves or bag when it is up.3–4 minutes black, 1–2 green, 2–3 oolong, 3–5 white. This single habit fixes most bitter tea.
Never squeeze the bag.Squeezing forces out concentrated tannin, which is the harshest component.
Match the water temperature to the tea type.Boiling for black and herbal; 70–80°C for green; 80–90°C for white and oolong. Boiling water on green tea guarantees bitterness.
Use enough leaf rather than brewing weak tea for longer.One bag or teaspoon per 200ml. Under-dosing and extending the time is the classic route to stewed tea.
Do not leave a pot sitting on the leaves between cups.Decant into a second warmed pot, or use an infuser basket you can lift out.
Try filtered water if yours is hard.Hard water accentuates harshness and produces the scum on the surface.
Re-steep good loose leaf rather than brewing one cup for longer.Two shorter infusions give more flavour and less bitterness than one long one.
Add milk after brewing if you take it.Milk binds some tannins, which is why over-brewed tea is more tolerable with milk — but fixing the brew is better.

Tips

The scum on the surface of tea is a reaction between tea compounds and calcium in hard water. Filtered water or a squeeze of lemon prevents it.
Different black teas want different times — a delicate Darjeeling suits 3 minutes, a robust Assam handles 4 to 5.
If you like strong tea, use more leaf rather than longer steeping. Strength and bitterness are different variables.

Common mistakes

Leaving the bag in the mug — Extraction continues, so the tea gets progressively more bitter as it cools.
Squeezing the teabag — It releases concentrated tannin, the harshest fraction.
Boiling water on green or white tea — It scorches the delicate leaf and extracts bitterness almost immediately.

Questions people ask

Why does my tea taste bitter as it cools?

Because the bag or leaves are still in it. Tea keeps extracting, so a cup that tasted fine at three minutes is over-brewed by the time it is drinkable.

Does squeezing the teabag make tea stronger?

It makes it harsher rather than stronger. What comes out is concentrated tannin, which is the bitter, astringent fraction.