Fu Brick Tea: Golden Flowers and the Fahua Process

Fu brick tea is a compressed Hunan dark tea in which a fungus called Eurotium cristatum has been grown deliberately, appearing as small golden dots through the brick. The Chinese name for the phenomenon is jinhua, golden flowers, and the process of growing them is fahua, flowering. It is the only tea where a visible microorganism is a quality standard rather than a defect.

The brick is the most studied of all dark teas, partly because the fungus is conspicuous and partly because the tea was for centuries a staple in regions with no vegetables. Its research base is small and it is larger than that of any other dark tea.

What the golden flowers are

Eurotium cristatum is a filamentous fungus that grows on the leaf during the pile and the pressing. It appears as tiny yellow-brown cleistothecia, the fruiting bodies, scattered through the broken surface of the brick.

The fungus is not a contaminant. It is encouraged: the brick is pressed, then held in a warm humid room at about 25 to 30 Celsius and 75 to 85 percent humidity for several weeks, and the fungus colonizes the leaf during that period.

A brick with abundant flowers indicates that the fahua ran well. A brick with none had the wrong conditions, and a brick with mould had the wrong conditions in the other direction. The distinction between golden flowers and mould is a matter of species and appearance, and a musty smell is the tell.

The flowers are the reason for the tea’s reputation and they are not a drug. The fungus is part of the production, not an active ingredient in the cup, and boiling water does not deliver a live culture.

The border trade, which shaped the product

Fu brick was made for the tea-horse trade and for the pastoral regions of the northwest, where meat and dairy dominated the diet and vegetables were scarce. The tea was pressed into bricks for transport and traded for horses.

That market explains the style. It had to be strong, it had to keep for years, and it had to be cheap enough to be a daily staple. The result was a coarse brick rather than a fine tea, and the golden flowers were a by-product of the fermentation conditions that made it keep.

The tea is still drunk with milk and butter in parts of the northwest, boiled in a pot with salt. A drinker who has only had it brewed plain has not had the version the product was designed for.

That history is the answer to why a tea with a fungal culture became a commodity rather than a specialty. It was made for a market that needed calories and preservation, not aroma.

• Golden flowers are Eurotium cristatum, grown deliberately.
• The process is called fahua, flowering.
• The brick is held warm and humid for several weeks.
• Abundant flowers indicate a good fermentation.
• It was made for the northwest border trade.
• It is traditionally boiled with milk and salt.

Taste and brewing

The liquor is deep red-brown and the taste is earthy, slightly fungal and sweet, with a cooling finish. It is fuller and rounder than a plain hei brick and less aromatic than a Liubao.

Break the brick with a pick or a knife, using the grain rather than against it. A brick is dense and a careless break produces dust, which brews bitter.

Use boiling water, six to eight grams per 150 millilitres, and a rinse of ten seconds. The first infusion after the rinse is often thin; the second and third are the fullest.

Simmering is the traditional method and it suits the tea. Five grams in a litre of water held just below a boil for five minutes gives a dark, sweet, full-bodied drink that no steeped version reproduces.

Storage should be dry and ventilated. A brick kept in a damp room can grow the wrong fungus, and the difference between a good brick and a spoiled one is a smell that clears or does not clear after the rinse.

What the research shows

Fu brick has more published work than any other dark tea, and most of it concerns the fungus and the lipids. The lipid trials are small, typically thirty to a hundred participants for eight weeks to six months, and they report modest reductions in total and LDL cholesterol.

The mechanism proposed is bile acid binding by the theabrownins rather than a statin effect. Studies have detected lovastatin in fu brick, but at micrograms per gram, orders of magnitude below a therapeutic dose.

The gut bacteria work is the more interesting strand. The polysaccharides and fungal metabolites reach the colon, and the shifts reported are consistent with a prebiotic effect.

None of it establishes a health benefit. The trials are small and weak, and the traditional claims about digestion are not tested by any of them.

• Fu brick has the largest research base in dark tea.
• Lipid trials are small and short.
• The mechanism proposed is bile acid binding.
• Lovastatin is present at microgram levels, not therapeutic.
• Gut bacteria shifts are consistent but of unknown meaning.
• No trial has measured a disease outcome.

Buying and storing

Look for even flowers across a broken face. A brick with flowers only on the surface had a shallow fahua; one with them through the interior had a proper one.

Smell it dry and after a rinse. A clean brick smells sweet and fungal both times; a spoiled one smells of a cellar and the smell deepens rather than clearing.

Store it dry, dark and ventilated. A brick kept in a damp room can colonize with the wrong fungus, and the result is not drinkable.

Age improves a fu brick slowly and the flowers do not increase with time. A ten-year brick is smoother than a new one and it does not have more flowers.

How the brick is made, in order

The leaf is pile-fermented first, as with any Hunan dark tea, then sieved and blended. The blend is pressed into a brick under heat and pressure, which gives the dense block.

The pressed brick is then held in a fahua room at 25 to 30 Celsius and 75 to 85 percent humidity for three to six weeks. The fungus colonizes the leaf during that period and the flowers appear.

After fahua the brick is dried slowly and wrapped. The drying has to be gentle, because a fast dry cracks the brick and stops the fungus before it has finished.

The whole sequence takes two to three months, which is longer than most tea production and is why the product is made in batches rather than continuously.

What it pairs with

Fu brick is a strong, earthy tea and it suits fatty food. In the northwest it is drunk with mutton and with dairy, and the combination works because the tea cuts through the fat.

It is a poor match for delicate food, which it overwhelms, and for sweet pastry, which clashes with the fungal note.

A drinker using it as a table tea should serve it after the meal rather than with it, in the way the producing regions do.

The strongest traditional pairing is with milk and salt, boiled together. It is a drink rather than a tea in the way most readers mean the word, and it is worth trying once.

A note on how the brick is sold. A full fu brick is about a kilogram, which is a large commitment for a tea that a household may not drink often.

Most retail is in broken pieces or in smaller bricks, and a broken piece is a reasonable purchase because the tea inside is the same. The only thing lost is the object.

A drinker who wants to see the flowers should ask for a piece with the face intact, since that is where they are most visible.

One more point about the caffeine. Fu brick carries about thirty to forty milligrams per gram, which is a normal dark tea figure, and a simmered pot delivers most of it in the first few minutes.

A final note on the caffeine and the evening. Fu brick is a strong tea with a normal dark tea caffeine load, and a simmered pot delivers most of it early. A drinker who is sensitive should brew it earlier in the day and not treat it as an evening drink because it tastes mild.

Frequently asked questions