Drinks

Why your chai turns bitter, and the boil that causes it

Bitterness in chai is over-extracted tannin. It is a function of time and temperature, and the standard hard ten-minute boil guarantees it.

By 2 min read
A cup of milky masala chai.
Masala chai. Photograph by Dadhichbittu007, CC BY-SA 4.0, via Wikimedia Commons.

Key takeaways

  • Bitterness in tea comes from tannins, which extract more slowly than the compounds you want.
  • A short brew gets the flavour and colour; a long one keeps going and collects the bitterness.
  • Boiling the leaves for ten minutes over-extracts them by a wide margin.
  • Strength should be adjusted with more leaf, not more time.
  • Strain immediately; standing on the leaves continues the extraction.
Prep time
5 min
Cook time
10 min
Total time
15 min
Servings
2

Chai that dries the mouth and leaves a harsh edge behind it has usually been boiled far past the point where anything good was still being extracted. The leaves are rarely the problem. The clock is.

Not everything comes out at the same speed

Putting tea in hot water starts several extractions at once, and they run at different rates. Caffeine and the lighter aromatic compounds come out quickly. Tannins, the polyphenols responsible for astringency and bitterness, are larger molecules and come out more slowly.

That difference in rate is the entire technique. Take the tea off early and you have collected mostly the first group. Keep going and the first group is finished but the second is still arriving, so every additional minute is adding proportionally more bitterness and almost nothing else.

Temperature accelerates both, which is why a rolling boil reaches the unpleasant end of that curve much faster than a simmer.

More leaf, not more time

This is the single most useful correction, because strength and bitterness feel like the same dial and are not.

Adding a third teaspoon of tea gives you more of everything at the same ratio: stronger, but balanced the same way. Boiling for four more minutes gives you disproportionately more tannin. If your chai is weak, the answer is leaf. If it is bitter, the answer is time.

Ginger and cardamom want opposite things

Ginger takes a while. Its pungency comes from compounds that need a few minutes in hot water to come out in quantity, which is why it goes into the water before the tea rather than with it.

Cardamom is the opposite. Its character sits in highly volatile aromatics that will evaporate off during a long boil, so a cup that has been simmering for ten minutes smells far less of cardamom than the pot did at minute two. Crushing the pods and keeping the cook short gets more of it into the cup.

Strain it immediately

Extraction does not stop when the pan leaves the heat. A pot of finished chai standing on its leaves for five minutes while people find their cups is still getting more tannic, and it is measurably worse by the time it is poured.

The same applies to reheating. There is no way to reheat chai without the leaves having sat in it, so leftover chai is bitter chai. Make the amount you are going to drink.

Something cold instead

Bitterness from over-extraction shows up elsewhere too: a mint and lemon cooler goes bitter for a closely related reason, and the fix there is also about what you extract and for how long.

Ingredients

  • 300 ml water
  • 200 ml whole milk
  • 2 tsp strong black tea, CTC or a robust broken-leaf Assam
  • 2 tsp sugar, or to taste
  • 15 mm piece of ginger, crushed
  • 2 green cardamom pods, crushed
  • 1 clove and a small piece of cinnamon, optional

Instructions

  1. Bring the water to a boil with the crushed ginger and whole spices. Simmer 2 to 3 minutes so the ginger has time to give something up.
  2. Add the tea. Simmer 2 minutes and no longer. The liquid should be a deep reddish brown.
  3. Add the milk and the sugar. Bring back to just below a boil.
  4. Hold it there for 1 to 2 minutes. If it starts to climb the pan, lift it off and return it.
  5. Strain into cups immediately. Do not leave it standing on the leaves.

Recipe tips

  • Crush the cardamom and ginger rather than slicing. More broken surface means faster extraction, so you need less time on the heat.
  • If you like it stronger, add more tea. Do not boil for longer; those are not the same adjustment.
  • Cardamom is aromatic and volatile, so a shorter cook keeps more of it.

Serving suggestions

  • Strain the moment it is ready. The pot is not a holding vessel.

Storage

  • Chai does not keep. Reheated chai is bitter chai, because the leaves kept extracting while it stood.

Sources

  1. Tannin
  2. Masala chai

Frequently asked questions

It is a very common method and it produces a strong, dark, tannic cup that plenty of people prefer, particularly with a lot of sugar and milk to balance it. The point is that the bitterness is a choice rather than an inevitability. If your chai tastes harsh and you did not want it to, the boil is the thing to change first.

It changes the extraction rather than stopping it. Milk proteins bind some of the tannins, which softens the perceived bitterness, and the milk raises the boiling point slightly. Many household methods boil everything together for exactly this reason. It masks over-extraction rather than avoiding it.

Extraction happens at broken surfaces. Crushing a cardamom pod exposes the seeds inside; leaving it whole means most of what is in there never reaches the water. The same applies to ginger, where a crushed piece gives up far more in two minutes than neat slices will.

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