Why Does My Tea Taste Sour, Flat or Weak? A Troubleshooting Guide

Most off tastes in tea come from brewing, water or storage, not from the tea itself. Sour tea usually means water that's too cool for the leaf (typical with oolong, pu-erh and red tea), stale or damp tea, or tea left sitting too long. Flat tea usually means stale leaf, distilled or reverse-osmosis water, re-boiled water or cold teaware. Weak tea means too little leaf, steeps that are too short, or water that's too cool. Bitter and drying tea means the opposite: too hot, too long or too much leaf. Change one thing at a time and taste again.

I'll be honest: I spent a whole winter convinced I'd been sold a bad batch of Da Hong Pao. Every cup was thin and faintly sour. I was about to write a grumpy message to the seller when a friend asked what temperature I was using. "About 85, like my green tea," I said. She laughed. The next session, with water straight off the boil, the same tea was rich, sweet and roasty. The tea had been fine all along. I hadn't.

Quick diagnosis#

Why tea tastes sour#

Sourness is the most confusing off taste, because people often assume the tea is bad.

1. Water too cool for the tea#

The most common reason by far, especially if you started with green tea. Roasted oolongs, shou and aged pu-erh and dark teas need water at 90 °C to boiling, and red teas 80–95 °C. Cooler water pulls out the lighter, sharper compounds but not the sugars and body, so the cup tastes thin and sour. If your oolong or pu-erh is sour, try hotter water before anything else.

2. Stale, damp or badly stored tea#

Tea that's old or has picked up moisture can taste sour and flat. If it also smells musty or damp, stop drinking it. See how to store tea.

3. Tea left standing#

Tea poured and forgotten for half an hour changes: it cools, the aroma fades, and it often turns dull and slightly sour. This is one reason gongfu uses small steeps drunk right away.

4. The tea itself#

Sometimes it really is the tea. A light, fresh, under-roasted oolong can have a sharp, sour edge; so can a poorly processed one. Some young sheng pu-erh has a natural fruity acidity, which is normal and pleasant if it's clean. Harsh, lingering sourness that survives hot water and fresh leaf is a quality problem.

Why tea tastes flat#

• Stale tea. Aroma is the first thing to go, and aroma is most of what we call flavour.
• The wrong water. Distilled and reverse-osmosis water make tea taste empty. Very hard water makes it dull. Soft filtered or spring water is best: see the best water for tea.
• Re-boiled water. Water boiled again and again tastes flatter. Use a fresh boil.
• Cold teaware. A cold gaiwan and cups steal heat and aroma. Warm everything with hot water first.

Why tea tastes weak or watery#

• Not enough leaf. The most common mistake in gongfu is using Western amounts. Weigh it: roughly 5–7 g per 100 ml for oolong, 3–5 g for pu-erh and green tea.
• Steeps too short for the tea or for a later steep. Add time each round.
• Water too cool. See above.
• The tea is spent. After enough steeps, every tea turns watery: see how many times can you steep tea.

Why tea tastes bitter or drying#

Bitterness and a rough, drying feeling come from over-extraction: too hot, too long or too much leaf. Green tea and bud-heavy teas are the most sensitive; young sheng pu-erh is naturally strong and needs short steeps. The full guide to green tea is why is my green tea bitter.

A light bitterness that turns quickly into sweetness in the throat is normal and valued. Harsh bitterness that lingers is not.

Fix it in this order#

When a tea tastes wrong, change one thing at a time, in this order:

1. Water temperature. Match it to the tea: see my gongfu brewing chart.
2. Leaf amount. Weigh it.
3. Steep time. Shorter if bitter or drying; longer if weak or sour.
4. Water quality. Try soft bottled or filtered water.
5. Teaware. Warm it; make sure it doesn't carry old smells.
6. The tea. Only now blame the tea.

My side-by-side: the same Da Hong Pao, two temperatures#

The only thing that changed was the kettle.

Off tastes that aren't mistakes#

• Young shou pu-erh can taste of the wet pile: earthy, slightly "pondy". Two rinses and a few weeks of air help; so does time.
• Fresh-roasted oolong can taste sharp and smoky for a while. A few months of rest softens it.
• Young sheng pu-erh is bitter and bracing by nature. That's what it is when young: see sheng vs shou.

Myths#

"Sour tea is always spoiled." Usually it's just under-extracted. Try hotter water first.

"Purer water is better for tea." Distilled and RO water make tea taste flat.

"More leaf always means more flavour." Past a point, it means more bitterness and a rough, drying feel.

"If it's expensive, it can't taste bad." Brewing and water can ruin any tea.

My honest take#

Before you decide a tea is bad, brew it three times, changing one thing each time. Nine times out of ten you'll find the problem in your kettle, your scale or your tap. And if it's still sour, flat or harsh after that, then it's the tea, and you'll know for sure.

The bottom line#

Sour tea usually means water too cool or tea that's stale or left standing. Flat tea means stale leaf, the wrong water or cold teaware. Weak tea means too little leaf, too short or too cool. Bitter and drying tea means too hot, too long or too much. Fix one variable at a time, starting with temperature. For the full method, see my gongfu tea guide.