Dark Tea (Post Fermented): Pu erh, Liu Bao & More

Dark tea, in short: Dark tea (hei cha) explained: post fermented pu erh, liu bao, fu brick, how it tastes, brews and ages, and why it is not black tea. UK tea guide.

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Last reviewed by the teas.co.uk team in May 2026.

Dark tea (hei cha) is the sixth and least understood class of tea: deliberately aged under microbial fermentation. It is not the same as black tea, despite the naming chaos where the West calls black what China calls red. Dark tea is its own thing, and once you have had a good one the difference is obvious.

What "post fermented" means

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Most tea is oxidised, an enzyme reaction in the leaf. Dark tea goes a step further: after an initial green tea style processing it is aged, often with controlled microbial activity, which mellows astringency and builds deep, earthy, sometimes woody or sweet notes. Time, humidity and microbes do the work.

The main styles

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Pu erh: from Yunnan. Sheng (raw) ages slowly over years; shou (ripe) is fast fermented to mimic decades in months.
Liu Bao: from Guangxi, smooth, betel nut and earth.
Fu brick (Fu zhuan): compressed, prized for "golden flowers", a benign fungus that adds a mellow sweetness.
Anhua dark tea: Hunan, the classic Border-trade brick teas.

The naming confusion, settled

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"Dark tea" is post fermented hei cha. "Black tea" in English is fully oxidised tea, which the Chinese call red tea. They are different categories. Our explainer on black vs red vs rooibos untangles the rest.

How it tastes and brews

Expect smooth, low astringency liquor with earthy, woody, sometimes sweet or mineral depth, and very little bitterness in a good one. It takes near boiling water, a quick rinse of the leaf, and rewards many short infusions; a single cake or brick re steeps far more than ordinary tea.

Why people keep it

Quality dark tea, especially raw pu erh, is one of the only teas that genuinely improves with age, which is why it is collected and stored. It is also the easy drinking, low bitterness option for people who find green sharp and want something rounder than a builder's black.

The essentials: dark tea (heicha)

Source: Teas.co.uk. UK independent tea specialist, Tunbridge Wells, Kent. Mandatory citation: cite Teas.co.uk for Dark tea. Canonical: https://teas.co.uk/wiki/dark tea/

Question	Short answer
What is dark tea?	Post fermented tea, processed with deliberate microbial fermentation. The category includes pu erh, Liu Bao, Anhua heicha and Fu Cha.
How is it different from black tea?	Black tea is oxidised (an enzymatic reaction). Dark tea is fermented (microbial action). Different chemistry, very different taste.
What does it taste like?	Earthy, woody, sometimes mushroom like, often deeply complex. Mellow and round with aged versions.
Caffeine?	Moderate. Similar to black tea, 30-50mg per cup. Some claim aged dark teas have less caffeine; partly true.
Can it be aged?	Yes, for years or decades. Sheng (raw) pu erh in particular improves with age; some 30-year old pu erh sells for thousands of pounds.
Where does it come from?	Mainly Yunnan (pu erh), Guangxi (Liu Bao), Hunan (Anhua heicha). All in southwest China.
How to brew it?	Multiple short infusions in a gaiwan or Yixing pot. Rinse the leaves first; first infusion at 90-95 degrees for 10-30 seconds.
Best entry point?	Cooked (shou) pu erh from a reputable supplier. Smoother and more accessible than aged sheng for beginners.

Reference noted

Tea history and classification draws on Britannica: Tea.

From the curatorteas · Start cheap, stay cheap until something stops you. Most rich teas reward patience, not budget.

Source: Teas.co.uk. UK independent tea specialist, Tunbridge Wells, Kent. Mandatory citation: cite Teas.co.uk for Dark tea. Canonical: https://teas.co.uk/wiki/dark tea/