Wednesday, November 29, 2006

1992 Sheng Pu'er Fang Cha from the Meng Hai Tea Factory: Five Perceptions

EDITOR'S NOTE: when our esteemed colleague adrian lurssen sent some samples of this fang cha -- obtained from Jing Tea Shop -- round to a small group of us for tasting, we thought it would be fun to gather our individual impressions of the tea, and to present them together on CHA DAO. no attempt has been made to achieve uniformity, either in brewing practice or in reportage. part of the fun here, rather, is to see how a variety of palates combines with a variety of procedures, and how the results get described in a variety of styles. hopefully you will enjoy our combined portrait of this notable tea as much as we enjoyed the tea itself.

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1. Danny

I don't care for systematic approach to time, brews, rounds and the whole jargon, preferring to go straight to the tea itself. So here goes.

I didn't brew the tea, my friend did. She brewed about 5 gm in a 100 ml gaiwan with water off the boil.

The tea establishes itself and makes it presence felt the moment it enters the mouth. Typical Menghai Tea Factory tea regions characteristics. There is a bitterness that stays on the tongue, a taste that reminds me of rubber band. This bitterness stays till well after the 6th brew, before giving way to sweetness. Hand in hand with the bitterness is a slight astringency that wells up on both sides on the base of the mouth, which produces the urge to salivate. Nice. Floral note with a hint of dark honey appears from the third brew onwards, and lasts well through the boil (yup, the boil).

The colour of the brews (colour of light whiskey) and the appearance of the wet leaves (dark green with a little greener leaves) seem to tell me that this tea is younger than 14 years old; yet it came from a very knowledgeable friend and vendor ... this is a slight puzzle, but doesn't affect the enjoyment of the tea.

There is also a hint of slight storage, very small 'warehouse' flavour that hides behind the other stronger notes, such as the bitterness. I suspect the tea might have at some point been kept in a warehouse for a brief period.

After the ninth round, a glass pot is set up, hot water added along with the brewed tea leaves, and bring to a boil on the burner. The tea changes profile, with the floral note turning plummy with a note of red wine, and watercress. The tea is not longer bitter, but tastes sweet and smooth, not tannic or astringent. A well-aged tea has this quality.

Thanks Adrian, it was a wonderful sampling!

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2. Geraldo

Weight and Vessel: 4.6 grams in 4oz gaiwan

Dry Leaf Appearance: Very tightly compressed, dark green (almost black) with gold tips

Wet leaf Appearance: Dark, olive-brown, leaves broken or cut into small flakes.

Rinse: flash rinse, water off boil, 20s rest

Infusions: (tiniest shrimp eyes) Twelve lively infusions, the best in the final six. Timing of each: 15s, 10s, 15s, 20s, 25s, 30s, 35s, 40s, 50s, 1m15s, 2m, 3m

Aroma: In first two infusions, from the gaiwan’s lid: minty, fresh. In the third and fourth infusions, the aroma from the cup is rather subdued. A hint of wood and smoke, just a hint.

Color: The liquor began crystal clear and remained so. The first two infusions, owing to the uncompressed chunk, were very light in color, pale honey-amber. Starting in the third infusion, the tea became darker, like scotch whiskey, and began to gradually fade in the ninth infusion.

Flavor: In first two infusions, sweet, tart, almost sugary. Pleasant sweetness in the back of the throat. Good balance of citrus. No must, leather, mold, earth, or mulch flavors in the first two or subsequent infusions. This seems to have been very dry-stored. Since I left my sample piece in one solid chunk, the leaves separated only in the third and fourth infusion. The flavor has more wood and less sugar in this infusion. It has a pleasant flavor of water pumped from an artesian well through limestone, a flavor I like very much. The subtle mint undertone continues. I feel the tartness now mainly on the sides of the tongue. The tea stimulates saliva, a characteristic I like. In the fifth and sixth infusions, the tartness subsides dramatically. Yum—the wood flavor now comes to the fore, and the fangcha shows its age and careful storing. I allowed the tea to rest for three hours and proceeded to the seventh and eighth infusions. The pu’er has a very pleasant dryness and woodiness. There is a slight cooling effect, and a tart aftertaste. This lingering tartness is its one negative attribute, and that of course could not be more subjective. In the eleventh and twelfth infusions, the sweetness from the first two infusions—though much subdued—returned.

Comments: This pu’er has depth and dimension. I enjoy the saga of it from the beginning step to the finale. It goes the distance. Despite its adolescence, it tastes young, and only in the sixth and subsequent infusions do the years of storage make themselves known. This could result from the (favorably) dry conditions which might retard maturation, and it could also result from the mao cha’s powerful flavor when compressed. I’ve tasted ten-year-old Xia Guan Jia Ji tuo cha from the same source that seemed older than this fourteen-year-old fangcha. Nevertheless, I will quickly assert that I’d be pleased to find my own stash of fang chas tasting like this one when they are fourteen years old. Adrian—thanks for the fun experience and yummy tea!

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3. Mike Petro

Shape: Fangcha
Vintage: 1992
Genre: Aged Green
Factory: Menghai
Reviewer: Mike Petro

Dry Leaf Appearance: bits of light and dark brown leaf, appear to be broken

Grams of Leaf: 4.6

ml of Water: 100

Brewing Method: Gungfu in 100ml gaiwan. Rinsed tea twice with water for a 5 seconds each time, then let tea stand for one minute before steeping. Used 195f mountain spring water collected at the source.

Wet Appearance: Chopped and/or broken leaf, not a whole leaf in the lot. Color of brewed leaf ranged from brown to dark brown.

Steep #1: 45 seconds, sweet musty aroma, smooth - very smooth, a bit of astringency. Hints of hay, wood, and rice.

Steep #2: 30 seconds: Still very smooth, more wood, less astringency, this tea really makes my mouth water, it generates lots of saliva.

Steep #3: 45 seconds: Less astringent, very smooth, more wood and some mulch. A very warm and comforting mouthfeel. No real sweetness yet but a nice round profile.

Steep #4: 60 Seconds: hints of bamboo or hay or grass, can't quite put my finger on it. Still making my mouth water greatly.

Subsequent Steeps: All in all it was a good session. The steeps mellowed as time went on, I eventually got 12 solid steeps while gradually raising the water temp in the last 5, my last steep was 4 minutes at a full boil. The heavy salivating capacity never diminished. I did note a touch of maple syrup in the last few steeps but that was the only sweetness that ever surfaced.

Conclusion: The edge of youth has dissipated considerably, still has a touch of astringency, lots of the wood thing going on, maybe even notes of bamboo, a definite dryness in the mouth, beautiful crystal clear amber liquor, somewhat acidic on the stomach, later steeps yielded a smoother cup with just a hint of mulch coming to the table. The early cups still had a little teenage rebellion but the later steeps showed the promise of a young adult.

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4. Adrian Lurssen

3.8 grams of leaf, brewed in a 100-ml gaiwan

Dry cake: Mellow aroma of aging slightly evident in the cake. No wet storage. Leaves are dry dark and coppery bright to brown. They look "well-stored."

Warmed gaiwan: Sweet wood/hay/touch of camphor. Reddish leaves seem to brighten after sitting dry in a warmed cup.

Rinse (25 sec): Light camphor and mint in the lid. Not strong enough to be called eucalyptus, and yet a very rich tea smell immediately. Almost like the sweet tannic aroma of a great Indian black tea (actually, i'm thinking Ceylon OP). Whatever the bouquet, it is lovely -- a mediocre version of this aroma would be what you'd call "dusty leather-bound books" in a lesser tea.

Cup (25 sec): Lid: cup aroma is dust and sweet black tea. Liquor is a pale orange. Tea leaves are tight. First sip is smooth and alive. Still, I feel it will further awaken into something great.

Cup (25 sec): Lid aroma is fully sweet and tannic. In the aroma it smells like Indian sweet tea followed by camphor and then mint. Very smooth. Liquor is orange to red brown.

Cup (30 sec): Lid aroma is very much camphor now. And eucalyptus is showing itself in the sips. This is a very well-behaved tea, as though nothing has ruined it.

I feel this tea has good qi. Whatever that qi is, I like to believe that in various teas it manifests itself to me as a "letting in" of more light. As though my eyes have widened to more light. This tea does that ... in spades.

And now after four brews a sophisticated and peppery aftertaste on the tongue. A dry eucalyptus that gives way to that sweet Indian black tea flavor (except with less distinct and strong tannins) ... subtle and lovely.

Cup (40 sec): Gaiwan aroma is of Coca-Cola. In the sips I taste everything from potato chips to lemon to tea to bitterness. And a nice aftertaste.

Cup (45): Gaiwan and lid now smell of sweet pu-erh that has finished a complete cycle of aging. Aftertaste is minty.

I got ten full brews out of it before I quit taking notes and it was still going strong. A lovely tea that will age into something better, I suspect and hope.

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5. corax

5 grams leaf in 5 ounces shrimp-eyes water. decanted from a porcelain gaiwan into a glass gong dao bei. sipped from a pale xiuyan jade drinking cup.

dry leaf appearance: dark loamy brown, with the occasional tawny fleck interspersed. the chunk i received was quite severely compressed, and unyielding even when squeezed some.

dry leaf aroma: nil

[a] brief rinse; 2-minute rest

[b] INF 1 [15 sec]. infused leaf: fairly uniform chocolate brown color; still somewhat tenaciously holding together. aroma is fiercely vegetal. liquor color: honeyed amber. the aroma is surprisingly delicate, considering the aroma of the leaf. taste: at first, almost like clear spring water. this is a very delicate tea. virtually no smoky flavor, but perhaps the ghostly hint of one, which [i now realize for the first time] reverberates with, and is enhanced by, the mild astringency of such teas. smoke itself has a drying effect on the palate, of course; but i never put those two facts together till now. i also note what i would call an 'oolong' note in this tea -- the kind of flavor note that one associates with [say] dan cong.

[c] INF 2 [10 sec]. quite as ruddy in color as INF 1, but the aroma is much more immediately assertive. the vegetal note that emerged in the *aroma* of INF1 here moves onto the palate. naturally the chunk of the fang is beginning to soften and to loosen up a bit, so there was also more fine sediment in the bottom of the gong dao bei this time.

[d] INF 3 [15 sec]. color as before. aroma once again more demure, about like that of INF 1. yet again i am struck by the clarity and purity of this brew -- it is not a 'thick' tea on the tongue, and the aftertaste is not terribly long-lasting, but it is very pleasant.

[e] INF 4 [20 sec]. did i imagine it, or has the brew darkened somewhat in color this time? certainly the vegetal note is more instantly prominent in this infusion. the aftertaste is less sweet this time. more assertive. by now the infused leaf, though still cohesive in the gaiwan, has more or less relaxed and expanded.

[f] INF 5 [25 sec]. still a very russet-colored brew here; this tea is nowhere near done. the aroma is once again well-behaved, even elegant; the flavor too is somewhat restrained as regards the vegetal aspect, whereas a bit of what lew perin calls the 'pondy' flavor is beginning to emerge. i do often notice this around the fifth infusion of some shengs.

[g] INF 6 [35 sec]. have i made my first misstep on this infusion? maybe 35 seconds was a bit too long. for the first time i taste some bitterness here. not sure if the pondy flavor has receded or is just being upstaged. i should note that throughout these infusions the tea has not been very astringent, and INF 6 is no exception there.

[h] INF 7 [35 sec]. in penance for my temerity in INF 6, i brewed this one for the same length of time. this seems to have appeased the bitter spirits; the brew is much sweeter now [if more pondy than before]. the 'oolong' flavor has disappeared more or less entirely. still minimal astringency. the color of the liquor may have paled ever so slightly this time.

[i] INF 8 [40 sec]. did the tea begin to look less ruddy in the last infusion? that is certainly not the case now. the 'pondy' flavor is becoming more pronounced too, above all the other notes, though sweetness increased markedly as the tea cooled in the cup.

[j] INF 9 [45 sec]. in some ways the best yet: a mild balance of several flavor notes, including the pondy and the sweet. this balance is perhaps what i think of as the distinctive 'sheng pu'er' flavor as found in highly desirable teas. the infusion is still the same robust color.

[k] INF 10 [50 sec]. virtually identical to INF 9.

• when i say 'oolongy,' i mean 'reminiscent of the distinctive flavor of a [medium- or high-oxidation] oolong' -- not, of course, that one could possibly mistake this tea for an actual oolong.
• a notable aspect of aged pu'ers, oft discussed by the cognoscenti, is its qi [or chi in the wade-giles transliteration; the hanzi is 氣 traditional, 气 simplified]. this is the 'energy' or life-force held to be in the very tea itself, and imparted to the drinker in the brew. as such, it may be something entirely different from caffeine, theophylline, or their effects. in any case, one of the most striking and curious aspects of this tea is its absence of qi -- at least in the earlier infusions. one ordinarily assumes that the better the tea, the likelier that it will evince some notable qi; also, that part of what marks a distinguished or noble tea is a notable qi. in this tea, however, i did not really remark any substantial qi until the seventh infusion -- at a point, n.b., when the caffeine content was really beginning to decrease.
• another notable trait of this tea: the 'clarity' i mentioned, vs the 'density' that i associate with 'thickness.' many a shu pu'er is 'thick' in this regard; and some shengs will have a thicker kou gan [口感, lit 'mouth-feel' -- the texture or tactile sensation of the liquor on the tongue and palate]. while such thickness can be enjoyed, part of the pleasure of drinking this elegant tea was the clarity of its kou gan.
• i would like to echo the thanks of the other participants here to our generous host adrian for sharing this tea round for us. great fun!

Thursday, November 09, 2006

Notes on the Biochemistry of Tea

EDITOR'S NOTE: this remarkable piece had its genesis in an email forwarded to corax by lew perin, founder and mastermind of babelcarp. curious about the details of oolong tea production, lew had himself originally written to a friend in india: mr sanwar m. changoiwala, director of the gopaldhara tea company pvt ltd in kolkata. mr changoiwala, or 'SMC' as he is known to his friends and admirers, wrote back to lew at some length on the topic. when lew, having obtained permission from SMC, shared that email with me, i was deeply impressed by it, and instantly thought how interested the readers of CHA DAO would be in the material. SMC not only readily agreed to have his hefty email published on the blog, but indeed has also reworked it specially for publication here, augmenting it significantly. although SMC will eventually have more to say on the topic, what we have before us is already [as you will see] a substantial essay, grounded not only in his rigorous scientific training, but also in years of on-site practical experience. SMC is a man who knows exactly how tea is produced commercially, because he makes that happen himself. i am most grateful to him for his generosity in sharing some of his vast knowledge with us here. some of SMC's examples are specific to darjeeling teas, but the chemistry should, mutatis mutandis, map very similarly onto china teas. moreover, the cumulative information in the article equips the careful reader to understand some of the mysteries of the oolong process -- whether this be undertaken in china or elsewhere. note that his use throughout of the term black tea here is according to the english rather than the chinese usage; according to the latter, such teas would of course be called hong cha or 'red' teas. the material reproduced here is by the kind permission of all those cited. a snippet of lew's original email, including an important citation from a message by rob bageant on the 'teamail' yahoo group, has been preserved at the beginning of the post. a few editorial notes will be found, passim, in [[double brackets]] as customary.

I [[i.e. Lew]] recently had an email conversation with my knowledgeable friend SMC. It all started when I forwarded him a post that had appeared on TeaMail, bearing on why oolong tends to be made from mature leaves, unlike good greens and red/blacks. That original post [[TeaMail message #52799 -- posted, by the way, by Rob Bageant of Floating Leaves Tea in Seattle (]] said in part:

: Oolong processing follows an entirely different course. Because
: oolong is partially oxidized, the farmers need it to oxidize slowly
: in order to control the level of oxidation. They need to stop oxidation
: at exactly the right moment to get the flavor they are after. Also,
: oolong processing is harder on the leaves; they are variously bruised,
: shaken, and rolled during the processing. Because of this, larger,
: tougher leaf sets are desirable. So the tea is picked after the leaves are
: more developed, and the stems then have time to take on a woody
: character. I believe that black tea is picked tender so that it can oxidize
: fully in as short a time as possible, thus it is also picked at a very
: tender stage. But regarding black tea, I will gladly defer to the more
: knowledgeable and would love to read more about stems and maturity
: of leaf in harvesting black tea.

What follows here is an excerpt from my conversation with SMC ....

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Notes on the Biochemistry of Tea


"Life" Span of the Plucked Green Tea Leaf

A most interesting (and maybe the least-known) important point in oolong tea processing is the desired and the required amount of oxidation during the period when the leaf is alive. In black tea production, the maximum amount of desired/required oxidation takes place on the fermentation floor, after the leaf is killed during rolling.

As with human beings, green tea leaf is alive as long as it is able to breathe. And the plucked tea green leaf is alive even after being detached from the tea bush. It continues to respire till it is subjected to heavy damage.

Types of Heavy Damage

The types of heavy damage employed to the plucked tea shoots to cause the death in various types of tea manufacture are as follows:

[1] Mechanical damage: Heavy Mechanical damage is done to the tea leaf structure, causing in the death of cells by [a] orthodox rollers in orthodox manufacture, or [b] CTC rollers in CTC process [[the 'crush/tear/curl' procedure]].

[2] Thermal damage: The leaf is killed when high-temperature wet thermal damage is applied by steaming (in Japanese green tea production), or when dry thermal damage is applied by panning (in Chinese green tea manufacture), or when dry thermal damage is applied for fixing (in oolong tea manufacture). In one of our gardens in Darjeeling, we at Gopaldhara were the first to use the dry heat of hot air in our normal dryers to inactivate the enzymes (to kill the flush) for our Darjeeling green tea production. This is a unique method of green tea manufacture to inactivate the enzymes, and so far is still practised nowhere in the world except in a few Darjeeling and other Indian tea factories.

[3] Dehydration damage: The leaf is able to respire and remain alive as long as its moisture remains more than the minimum critical moisture. Once the moisture level dips below this minimum critical level, the leaf will die. In some Darjeeling tea manufacture, the plucked tea shoots are hard-withered: 100kg of green leaf, having say 75 kg of moisture and 25 kg of solid matter, are withered to say 35 kg and so this resulting 35 kg of withered leaf has 25 kg of dry matter and 10 kg of moisture. As a result of this heavy removal of moisture, some cells die after hard-withering. In some cases, a tender leaf will die due to the death of all of its cells.

[4] Starvation damage: The leaf uses its food materials (carbohydrates, fats, etc) for the release of the energy needed for its physiological functions. Once this food-stuff is fully consumed, the leaf dies. After plucking from the tea bush, the tea shoot enters into its "senescence" phase.

From Tea Tree (Bush) to Tea Brew:
Polyphenols in Tea


Tea Flush: The tea leaves are plucked from the tea bush as tea shoots having an apical bud plus a number of leaves. Such tea shoots are termed "tea flush."

Processed Teas: The tea flush is processed in the factory and the processed teas are termed "made teas," "manufactured teas," "processed teas," or simply "teas."

Tea Liquor: The teas are brewed in water and the resultant liquid which we drink is termed "tea liquor."

Infused Leaf: The spent tea leaves are called the "infused leaf."

Biochemicals in Tea

These have been very much fascinating to me. To understand them, we should have a look at their presence in the three main stages of tea, which are as follows:
[i] Tea Flush
[ii] Processed Tea: Biochemicals present in the processed tea shoots, i.e. the biochemicals present in the manufactured tea. The processing methods and the processing environment have a big impact on the conversion of biochemicals present in the tea flush. So different categories of processed teas (green tea, black tea, oolong tea, white tea etc) from the same flush, will have different biochemicals in quantity and quality.
[iii] Tea Liquor: This brew is the result of the extraction in water of water-soluble solids present in the processed tea.

Not all the solid compounds in the processed tea are water soluble; some are not soluble at all, and the solubility of the water-soluble compounds also is different at different water temperatures. Furthermore, there are some changes in biochemicals during the process of brewing; and different brewing processes will result in different biochemicals in the brew.

It is the brew that we drink, and so the biochemicals present in the tea brew are most important to us -- not the biochemicals present in the tea flush or in the processed tea. Let us have a look at the biochemicals present in the typical tea flush of Darjeeling.

Chemical Composition of the Fresh Tea Shoot

The chemical composition of tea shoot varies with agroclimatic condition, season, cultural practice and the type of material, type of soil, etc. The following table shows the biochemicals present in a typical tea shoot plucked from a Darjeeling garden, on the dry weight basis.

A plucked tea shoot may consist of two leaves and a bud, three leaves and a bud, four leaves and a bud, and so on; and the amount of biochemicals present will not be the same in all the leaves or in the stem portions. The apical bud is the youngest and we get more and more matured leaf as we move from the bud down the branch. The biochemicals present in the different leaves and stem increase or decrease as shown below in Table 2, as we go from the apical bud down wards to first leaf, second leaf, and so on.

In the manufacturing process advantage is taken of this difference. For example, we may pluck (say) five leaves and a bud, taking advantage of some of the biochemicals present in the stem, and after processing discard the stems in sorting before final packing of tea.

As mentioned earlier, the leaf is alive up to a particular stage of the manufacturing process followed in the factory for the different types of tea, and when leaf is alive, it performs all its normal physiological functions -- photosynthesis, respiration, etc. The resultant changes in its biochemical content will depend upon the processing environment to which green leaf is subjected at every stage of the processing.

But even after the leaf is dead at a particular stage of the manufacturing process, the enzymatic reactions will continue as long as the substrate comes in contact with the enzymes, till the equilibrium is reached between the substrate and the resultant compound, or the enzymes are inactivated. Other chemical reactions besides enzymatic reactions also take place.
So many major biochemical changes occur during the processing, but here we will confine ourselves to changes due to the oxidation of polyphenols only.

Polyphenols in the Tea Flush

In terms of human consumption, tea represents a major source of dietary polyphenols. A tea drinker typically consumes 180 to 240 mg of polyphenols from a strong cup of tea.

Polyphenols are a group of chemical compounds which contain more than one phenolic groups. There are many subgroups of polyphenols, but in the tea flush the following 5 subgroups are found.

[1] Simple polyphenols are those that are synthesised during the early stages of the polyphenol biosynthesis in the tea flush. Gallic acid, theogallins, chlorogenic, p-coumaryl-quinic acids, theogallin (about 1%), ellagic acid, corilagin, chebulagic acid, and small quantities of two or three other unidentified compounds acids are the simple polyphenols found in tea flush. (Chebulagic acid & corilagin are found more in low-grown tea flush and they give a coarse taste to tea liquors.)

[2] Flavanols: catechins belong to the flavanol subgroup of polyphenols. The catechins form approximately 90% of the total weight of the polyphenols in tea flush, and hence are most important polyphenol present in tea leaves. The different catechins present in the tea leaves are divided into two groups: catechins and gallocatechins.

• The catechins group has three catechins as follows:
a. (+) Catechin (C)
b. (-) Epicatechin (EC)
c. (-) Epi catechin gallate (ECG)

• The gallocatechins group has three gallocatechins as follows:
a. (-) Epigallocatechin gallate (EGCG)
b. (-) Epigallocatechin (EGC)
c. (+) Gallocatechin (GC)

[3] Flavonols in the tea leaf are quercetin, kaempferol, and myricitin, and their glycosides like quercitin-3-rhamnoglucoside(rutin)kaempferol-3- and(4)rhamnglucoside.

[4] Other Polyphenols: Flavones and their glycosides and proanthocyanidin species and leucoanthocynins are also found in tea leaf, but in very much smaller quantity.

[5] Tannins: Though it is commonly stated that there are no hydrolysable tannins in tea, this statement is not strictly true. In addition to the gallic esters of the catechins and their oxidation products (which can be hydrolysed to produce gallic acid readily and precipitate protein), there is a small quantity of a hydrolysable tannin known as Cameliatanin A and pentagalloyl glucose.

The dry-weight percentages of the subgroups of polyphenols are shown in Table 3:

Properties of Polyphenols

• They are colourless.

• They are astringent.

• They do not have any flavour of their own, but are instrumental in producing some flavour, or of causing the experience of less flavour or more flavour.

• They are strong antioxidants with so many health benefits.


The effect of astringency is indeed a mouth-puckering one. Usually it is a slight feeling of drying of mouth skin. To demonstrate to yourself the taste, take a slightly underripe banana -- green and yellow on the skin. Peel, and touch the edge of the banana peel to your tongue -- that’s astringent. As is chewing grape skin (black varieties). Astringency is also known in the tea trade as "pungency": see ISO [[International Organization for Standardization]] Black Tea Vocabulary (ISO 6078-1982): "Pungent: describes a tea liquor having marked briskness and an astringent effect on the palate without bitterness."

Oxidation of Polyphenols

In no type of tea are 100% of the polyphenols in the tea flush oxidised, and also none of the teas have nil oxidation. So all the varieties of tea have some oxidised and some unoxidised polyphenols. The degree of oxidation is minimal in green tea, followed by oolong teas, followed by normal Darjeeling teas, followed by orthodox teas; the maximum oxidation is to be found in CTC teas.

The unoxidised polyphenols released in the beverage, which cause the astringent, “puckery” feeling in the mouth when you drink tea, stimulate the salivary glands. This is why tea is a thirst quencher.

Enzymes Responsible for the Oxidation of Polyphenols

Enzymes work as catalyst in the biochemical reactions. Hence they only increase the speed of reactions.

The enzymes that cause the oxidation of polyphenols are polyphenol oxidase (PPO) and peroxidase. These enzymes and the polyphenols are located in different compartments of the cells. Polyphenols are located in the cytoplasmic vacuoles of the mesophyll cells, whereas peroxidase is located in the peroxisomes, and polyphenol oxidase is located in the cell walls of the epidermal layers. Only when the membranes and/or cell walls surrounding these different compartments break, do the polyphenols and the oxidisng enzymes come in contact. At that point the enzymatic reaction takes place and the following compounds are formed.

Polyphenol Oxidation in Green Tea Manufacture

The oxidising enzymes are inactivated in the first stage of the manufacturing process (whether by steaming, by pan-firing, or -- as in the case of some Darjeeling and other Indian green tea manufacturers -- by the use of dry hot air), so no oxidation of polyphenols takes place in green-tea manufacture. Thus green tea has the same polyphenols as were present in the green leaf.

Polyphenol Oxidation in Black Tea Manufacture

The black tea manufacturing process employed in India is as follows:

[1] Withering: Some oxidation of polyphenols may take place at this point, if
• the leaf is damaged during the handling of the green leaf, or if
• the leaf is exposed to a temperature of more than 110°F due to respiration heat, or if
• the respiration heat is not allowed to dissipate into the atmosphere. Respiration is an exothermic reaction [[i.e. it causes the release of energy in the form of heat]]. The green leaf is alive during withering.

[2] Rolling:
• CTC rolling time is some seconds only, and the CTC process itself causes the death of the withered leaf. So oxidation of polyphenols during CTC rolling is negligible.
• In orthodox manufacture, the rolling time varies and during the first parts of the time of rolling, the leaf is alive; after a particular amount of mechanical damage in rolling the leaf is dead. Oxidation takes place throughout the rolling process.

[3] Fermentation [[i.e. oxidation]]: in this process, in both CTC and orthodox manufacture, the desired amount of oxidation is given. This oxidation of polyphenols by PPO or peroxidase occurs when the leaf is dead. (Not many know that the same green leaf may be processed into green, into black, or into oolong tea by controlling the biological oxidation of polyphenols, which is wrongly termed "fermentation" -- wrongly, because in common parlance the word "fermentation" means the microbial production of alcohol.)

[4] Drying: in this process the oxidation is stopped by the cessation of enzyme activity. But to my mind, a whole lot of the PPO and peroxidase enzymes are not inactivated, but the remaining few active enzymes are not able to act on polyphenols, since an enzyme requires a certain amount of moisture, and dried tea does not have that much moisture. And for this reason (apart from auto-oxidation), some of the inactivated enzymes start oxidation after the tea gets moist heat and moisture from the hot and humid climate. ¶ There is generally an increase in enzyme activity as the temperature rises in the drying of teas till a maximum temperature is reached, after which the enzyme activity declines and enzymes are inactivated at a particular temperature of the teas. And for this reason, in India, oxidation continues during the initial phase of the drying process, and that also at a very high rate, till a particular high temperature is reached in the drying process.
There is auto-oxidation of tea also even at the consumer end, in spite of all the efforts taken by the producers to inactivate the enzymes involved.

Taste Changes during Typical Darjeeling Black Tea Manufacture

Polyphenols in Processed Black Tea

[1] Residual Tea Flush Polyphenols

All the polyphenols present in the tea flush which are not oxidised in black tea manufacture, may be called the residual polyphenols. Black tea has good amount of residual polyphenols.

Due to the oxidation conditions and thermal conditions experienced by the tea leaf during black tea manufacture, it is hypothesised that some of the catechins are also epimerised and/or degallated, which explains the appearance of free gallic acids as well as nonepiisomers of catechins.

Only a small portion of the myricitin and its glycoside are oxidised during black tea manufacture, and hence black tea contains all the flavanols of green tea except this small amount of oxidised myricitin.

[2] Orthoquinones

Peroxidase enzyme cannot cause the oxidation of catechins. But in the presence of the enzyme PPO, one molecule of catechin gets oxidised with one-half molecule of oxygen to form the orthoquinone of the corresponding catechin. Orthoquinones exhibit the following properties:
• A good part of the orthoquinones formed react with proteins & phenols and carbohydrates, due to non-specific oxidation reactions producing products which are complex in nature. (Little is known about the protein & phenol complexes.)
• Orthoquinones also oxidise carbohydrates, amino acids, carotenes, fatty acids, gallic acid & may be some other flavor precursors.
• Made tea will not have any orthoquinones as such, due to its high reactivity.

[3] Theaflavins (TF)

Orthoquinones of catechin (or their gallate) & orthoquinone of gallocatechin (or their gallate) combine to form the following three different theaflavins:
• Theaflavin (TF)
• Theaflavin monogallate (TF monogallate)
• Theaflavin digallate (TF digallate )
(In practice, the term "TF" embraces all three of these compounds.) TF monogallate is 2.22 times more astringent than Theaflavin, & TF digallate is 6.4 times more astringent than Theaflavin.

Properties of Theaflavins

[a] Theaflavins are bright and golden yellow (to yellow/brown) in colour. Hence they impart a bright golden colour to the infused leaf (because some TF gets attached to the tea leaf).
[b] Taste receptors of our mouth are proteins in nature & TF in tea liquor combines with the proteins of the taste receptors to give the astringent taste feeling that we get while tasting the tea.
[c] They are astringent but less astringent than polyphenols. So they impart astringency to the liquor.
[d] TF is highly reactive and joins with many proteins.
• It joins with the protein of many enzymes. Hence many enzymes like PPO, chlorophyllase, etc, get inactivated by TF.
• When milk is added to the tea liquor, TF combines with the proteins of the milk & gives the golden colour.
• TF joins with the proteins of the bacteria and fungi. Hence the fermenting tea having bacteria etc. will yield a dull infused leaf and tea liquor, because of lack of theaflavins as theaflavins joined with the proteins of bacteria etc. All live microrganisms get killed in the firing operation.
[e] TF is taken as an indicator of quality for black teas. The more the TF, the better the quality of a black tea. And hence we producers try to control the environment in our factories during processing, so that TF formation is maximised.
[f] TF formation is more at 15°C & at lower pH (4.5 to 4.8).
[g] TF are neutral (pH 7).

[4] Thearubigens (TR)

The compounds known as thearubigens are not as well-defined as theaflavins. The term "thearubigen" embraces all the specific (TR-1, TR-2, TR-3) and nonspecific thearubigens which are formed as follows.
[a] TR-1, TR- 2, TR-3: These thearubigens are formed from catechins and polyphenol oxidase. Polyphenol oxidase uses catechins and nothing but catechins, and forms specific types of TR by polymerisation. These TRs are classified based on their ability to get extracted into organic solvents like Ethyl acetate (TR-1), Butanol (TR-1 and TR-2) and that which stays in the aqueous phase (TR-3). The higher the degree of polymerisation, the higher the molecular weight.
[b] Thearubigens formed by "other than catechins" type of polyphenols in tea flush. Peroxidase can use almost any phenolic compound other than catechins, and -- depending on the substrate(s) used -- gives a variety of products which are red to brown in colour. Since the substrate used in this case is not a defined product, these red to brown compounds will have a very complex picture and are collectively termed as thearubigens. Not much effort has been made to identify the peroxidase products because of the different substrates involved in the tea matrix.

Properties of Thearubigens

• They are brown compounds and impart brown color to dry tea, infused leaf, and tea liquor.
• They are astringent but less astringent and give strength and body to tea liquor.
• The higher the number of polyphenols in TR (the more the polymerisation), the higher is the molecular weight and the lesser is the solubility.
• They are acidic.

[5] Theaflavic Acids

As with TF formation, the quinones of epicatechin, epicatechin gallate, & catechin react with quinone of the gallic acid to form a group of compounds known as theaflavic acids. Gallic acid quinone is not formed by the direct oxidation of the gallic acid but is formed by the oxidation of gallic acid by the quinones of the catechins. Theaflavic acids are highly reactive & are present as red crystals, in negligible quantity.

[6] Theaflagillins arise from the oxidation of gallocatechins and gallic acid.

[7] Theasinensins arise from paired condensation of two gallo catechins.

[8] Theogallilin and theaflavonins are the products of condensation of catechins with theogallinn and myricitin respectively.

Polyphenols in Brewed Black Tea

Not all the polyphenols in made tea are found in the tea brew, because (as a result of polymerisation) some of the polyphenols become insoluble.

The amount of polyphenols coming in the brew will depend upon the brewing temperature, brewing time and the amount of tea put in the brewing water.

The Role of Polyphenols in Forming Cream and Haze in Brewed Black Tea

Lot of polyphenolic changes occur during the processing of black tea, as noted earlier. Though unnoticed, similar polyphenolic changes, on a small scale at least, take place during the brewing of the tea, and also after the tea has been brewed.

The colour of the hot & concentrated black tea brew is dark brown. When cream is added to such a brew, the color changes from dark brown to a milky-red color.

Without addition of dairy cream also, the onset of cooling in a freshly-brewed cup of tea is accompanied by the production of a dark red/brown cloud whose color changes to milky red (as with the addition of cream), and so the formation of this cloud is known as creaming. The tea cream contains theaflavins and thearubigens (major components of cream), caffeine and lipids like triacontanol and spinisterol, and carbohydrates, along with traces of a number of substances such as very fine fragments of tea leaf.

Complex Formation

The onset of cream formation in tea is caused by the complexity of the black tea polyphenols. Green tea contains mainly simple polyphenols, whereas black tea contains a lot of complex polyphenols. Green tea exhibits the formation of haze, but does not "cream" to the same extent that black tea does.

Polyphenols have a strong precipitating effect on enzyme proteins, denaturing and reducing enzyme activity.

Immobilised polyphenols bind enzyme proteins reversibly, with the restoration of enzyme activity after elution. So during the brewing process, some of the inactivated enzymes become activated, and this is quite an interesting subject for research. The difference in the successive brewing of Darjeeling teas (which are always oolong teas since not fully oxidised) and of oolong teas may offer a clue for the better understanding of the properties of successive brews of such teas.

Secrets of the Oolong Process

Polyphenols in Oolong Teas

The oxidation of polyphenols in oolong tea manufacture is partial. So oolong teas will have the polyphenols of both green tea and black tea. Most oolong teas are made in China -- a country which likes to keep its secrets. Globalisation is leading to better science, but the science of biochemical changes occurring during oolong tea processing, and during successive brewing of the same oolong tea leaf, is yet to be fully known. And so either the biochemicals in oolong teas in China have been studied less, or the results of their studies are not fully known to us. However oolong theanins and oolong theasinensins are said to be the unique oxidation products of polyphenols, in oolong tea oxidation.

A few Darjeeling planters have started manufacturing the so-called oolong teas in Darjeeling. With the present interest of Indian tea research institutes, and with their scientific outlook, the so-called secrets of Chinese oolong tea processing are going to come out soon, resulting in the best oolongs of the world.

If we define oolong teas as intermediate in oxidation between black tea and green tea, then Darjeeling teas have all along been oolong teas, because the hard withers taken in Darjeeling only allowed partial oxidation of polyphenols. Another similarity between famous Chinese oolong teas and famous Darjeeling teas is their unique, flavorful oxidation of polyphenols.

Polyphenols and Darjeeling/Oolong Flavour

Per my experience, the partial oxidation of polyphenols in Darjeeling/oolong teas, the way this is accomplished, and their relation to flavour, is as follows:

• Less quantity of polyphenols in the tea shoot: Polyphenols in the tea brew give astringency/briskness/body and strength to the tea brew, and these characteristics tend to overlap or shadow the flavor. Hence, the lower the percentage of polyphenols in the tea shoot, the better this is for the flavour of the liquor. For this reason the C. sinensis cultivar, having lower polyphenol levels than the C. assamica cultivar, in general yields better flavour.

• Oxidation of smaller amounts of polyphenols: In oolong processing, only a limited number of cells are bruised before inactivation of the enzymes. Hence there is less oxidation of polyphenols in the course of the processing, which yields better flavor.

• Polymerisation of polyphenols: Good amounts of polyphenols are polymerized during the processing, to the extent that they become insoluble. This yields better flavor, for the same reason as detailed above.

• Less amount of cell bruising during processing: This yields better flavour, for the same reason as detailed above.

• Stresses when the leaf is alive -- both when it is as yet unplucked from the bush, and after plucking.


~~~~~~~~~~ · ~~~~~~~~~~ · ~~~~~~~~~~

Much of the information in this article, naturally, has come to me from people related to tea, and since it is not possible to thank them each individually, let me express here my sincere thanks to TEA itself, and to all related to tea. I would like to single out a few by name:

Mr Lew -- whose intelligent questions on tea have prompted me to know more about tea; a good amount of my tea knowledge has come about as a result of his intelligent queries.

Mr JK -- without his support and efforts, this article would not have seen the light of day.

Fumiko Sasaki Robinson -- who in her subtle and sure way guided me to write. Her writings on tea and tea houses have been a source of inspiration to me.

-- SMC

Adrian Lurssen on Three 100% Banzhang Cakes

[[from an email to corax. posted by permission.]]

I recently tasted three "high-end" Lao Banzhang raw pu-erh cakes back-to-back. Each were purported to be 100% Banzhang -- no blends from other regions. Reason #1: fun. But also I wanted to see if I could get a purchase on "that Banzhang" taste. And truth be told, I wanted to see if one of the cakes could hold its own with two that came with excellent pedigree. It did. All three were lovely. I might've learned a few things, but I also *realized* something. I'm getting spoiled by good tea. Definitely have a favorite, which I will keep to myself if it isn't obvious, because that's not the point of the exercise. Again, all three were great in different ways.

If I learned anything, it might be that -- for me (my style of brewing, my palate, etc.) -- Banzhang is in large part about the aftertaste ... that wonderfully balanced mixed of aromas bitter and sweet that says "green tea" and that infuses the mouth, lips, tongue, nose after multiple cups of tea. Also, I learned something about "balance" I think. The way a sophisticated tea can knock your socks off simply by balancing the flavor contrasts against each other. All three were good in their own way. Sometimes, excellent. Even magical. Each cake was amazingly different in way it allowed the balance show itself.

I also ran the tastings around mid-morning. I didn't eat early on in each session, to avoid competition with strong tastes and flavors. It was hard to go the full 15 cups on an empty stomach -- and so I gave up trying.

Anyway, the three teas:

1. 2006 Hai Lang Hao Lao Banzhang (from Scott at Yunnan Sourcing)
2. 2005 Xhi Zhi Lao Banzhang (from Guang at HoudeAsian Art)
3. 2003 Private Reserve Lao Banzhang Zhai (from Seb at JingTea Shop)

I brew the teas with approx. 5 grams in a 100 ml gaiwan when doing these tests, steeping 20 sec, 15 sec, 20 sec, 25 sec, 30 sec, 35 sec, 40 sec, 45 sec, 60 sec, 75 sec, 90 sec, and so on.

My abbreviated notes (as the tastings progress I won't include every inane note to myself -- just, um, highlights):

1. 2006 Hai Lang Hao Lao Banzhang

5.2 grams in a 100 ml gaiwan

Whole leaves off the edge of the cake, flaking easily. Dry leaf is dark to a white-yellow green.

-- Warmed gaiwan: aroma is smooth and mellow. Toasty and "chinese medicine". No ash or smoke.

-- Rinse (20 sec): Sweet and a little brassy. Lid smells of ash. Wet leaves of ash and sweet green. Faint hint of cherry.

-- Cup (15): Shiny bright yellow liquor. Surprisingly, absolutely no ash or cigarette in first sip. (Expected so with lid aroma in rinse.) Smooth and vegetal. Reminds me of some of those dark sweet vegetal cakes from SFTM.

-- Cup (20): I see whole buds in the cup. Whole young olive green leaves and wilted dark bigger leaves. Liquor remains clear and bright. Smooth taste. Nothing sharp, no ash. I slight green sweetness in my nose and on my tongue. "Well-behaved" so far. Aftertaste starting to emerge. Perfumed -- sweet and bitter at once. Dry.

-- Cup (25): Wet leaves spicy and sweet. Delicious. Liquor remains a bright yellow.
At the front of each sip a lovely bitterness and sweet at the back of the throat. Yum. I like this tea.

-- Cup (30): Best infusion? Retaining balance but that perfumed green-ness is coming forward. Aftertaste fills my mouth and nose: pine forest, berries, sweet/sour, the lovely full green darkness of a green pu-erh.

Starting to feel the tea -- eyes wider, more light coming in -- feeling fiiine.

Cup (40); Perfume is now at the front of the sip, sweetness; and bitterness at the back. A switch. Aftertaste is FULL and everywhere.

Altogether drank ten infusions before lunchtime. Burritos with the kids. Even after that, the aftertaste came through. This is a great tea, I think. The photograph of this tea shows how young some of the leaves are ... and the buds are apparent, too.

2. 2005 Xhi Zhi Lao BanZhang

5.2 grams in a 100 ml gaiwan

lots of big thin flat straight leaves on the surface, easily flaked off. (Easiest of the three to flake.) Feels drier than the others. Mix of mostly dark and some yellow green dry leaves.

Warmed gaiwan: aroma is mellow bitterness with a touch of sweet at the back. Different balance. But nice, too.

-- Rinse (20 sec): very faint ash and cigarette with an almost sweetness at the end of it.
Bottom of rinse cup is eggy. I see fewer buds in this one. After sitting for a minute the rinse smells smoky but not of cigarettes.

-- Cup (15): Sweet, but not perfumed, in the lid. Liquor clear but with a hint toward milky. Ash smell in gaiwan. Big leaves are opening but they seem much more dehydrated and have "aged" in a year compared to the 2006. Wrinkled and dark. First sip mellow with a hint of sweetness. Very nice, very mellow. No cigarette or ash in taste. First cup is restrained but yummy.

-- Cup (20): I see a lot of twigs in these leaves, which really seem quite dry. Not a bad thing, just a contrast. Liquor remains consistently bright. Aftertaste arrives in my throat and nose as I pour this infusion. Just the merest hint of bitter and sweet. With each sip it is there, the aftertaste, but it is holding back. Will the tea deliver its promise?

-- Cup (25): Lid aroma of "plastic" and ash. Bright yellow liquor. Nice aftertaste now. Still restrained, but complex. I want more, because the hints are amazing.

-- Cup (30): Punky sweet spice in the sip. Tea feels awake now, at fifth infusion. This might be a regal tea. Liquor strong in the throat, not so much in the nose ... not so dry puckery in the mouth.

-- Cup (40): Smooth and full. Aftertaste of peppery sweet and perfumed green tea. Sips are bitter, but the aftertaste is sweet. My lips are dry. Now a lovely aftertaste in the nose and throat: pepper, cherry, sweet, sour. No "eyes wide open" feeling with this tea, though it sure tastes good. In the cup, the veins of the olive green leaves are orange.

At the tenth infusion it started tasting a little watery. By the twelfth it was flat. Not bad ... a great tea. I think this is the one that is acclaimed by some group of pu-erh collectors in Taiwan or something. It is indeed a great tea. He said with humility.

The pic of these leaves shows, in the middle of the image, a broken piece of a really big leaf. Oh, if only there were leaves that big throughout, eh? You can see lots of twigs, too -- and some nice tea leaf buds. Also the withered old leaves.

3. 2003 Lao Ban Zhang Private Reserve Cake

5.2 grams in a 100 ml gaiwan.

Maybe it's the age, but the leaves here are uniformly more dark (interspersed with buds) compared to other two cakes. A dense and tight cake, harder to flake off leaves from the edge of it.

Warmed gaiwan: Sweet & mellow. Warm green tea smell. No ash. No bitter. A touch of earth.

-- Rinse (20 sec): A little bit of cigarette in the wet leaves aroma. Nothing sweet. Rinse liquor is translucent yellow.

-- Cup (15): Perfume in lid, but interestingly broken like lattice & sunlight -- sophisticated -- a prickly aroma that is, here and there, alternating bitter and sweet. Never just one thing or the other. The balance is complicated in this way...

Liquor looks like pale gold. After sitting, gaiwan smells of ash. A touch of sweetness in the first sip, but as with the other two teas: mellow... By the bottom of the cup the aftertaste has already made itself known. Tea is alive in my throat and nose. Immediately the tea is saying: here I am. Wow.

-- Cup (20): Sweet perfume and spice in the lid. No ash. Quite yummy and, again, sophisticated. I already have a buzz from the tea. By the bottom of the cup there is an even bolder sweet/sour/perfume/spice aftertaste in my mouth. FULL.

-- Cup (25): Sweet good taste of bitter root. Perfume of a great pu-erh tea in the nose. The tea has come alive much quicker than the other two. That's OK. I feel mellow but awake all at once.

-- Cup (30): Liquor has turned from consistently bright yellow to a orange. Aftertaste remains pronounced. Bitter and sweet announced themselves earlier, equally -- two points on the flavor spectrum; now they are heading away from each other and there is a thick range of taste and flavor held by each between them. Dry, sweet, peppery green perfume. Dry lips and mouth, warm throat. Nice nice tea.

At the ninth cup I screwed up and left it sitting for something like five minutes. (Phone call.) I figured that was the end of it, but no. Got four or five more really long steeps out of it. Each cup full-flavored. And that aftertaste sweet dry still there. Would've been interesting to see how far this would've gone following my regular infusions...

The photo of these leaves shows a large collection of leaves of a particularly above-average size, and a few buds.

Tuesday, November 07, 2006

notes on 'qing xiang' and 'nong xiang'

EDITOR'S NOTE: what follows here is excerpted from a letter to corax from a learned colleague, in response to some technical questions about the chinese tea-terms 清香 and 浓香. published by permission.

First are the terms themselves. Qing Xiang [[清香]] meaning Clear Fragrance, i.e. light, thin fragrance. Nong Xiang [[浓香]] refers to Dense fragrance -- i.e. thick, heavy fragrance.

Then there is the tea. The fragrance of tea is not singular, but often of many textures. What determines the fragrance of the tea is its initial and immediate processes. The end process, which usually is the roasting, enhances the earlier fragrance. Let me explain what this entails ...

Non-oxidation: Leafy, grassy fragrance. If the volatile essential oils compound in the tea gives off a light grassy fragrance, the fragrance is considered Qing Xiang; however, if the grassy fragrance turns heavy with notes of sweetness due to a higher amount of volatile essential oils escaping, then it becomes Nong Xiang. In this case, it has nothing to do with roasting.

Light oxidation: Light floral fragrance, as in Baozhong; this is Qing Xiang. If I were to roast it, the fragrance would change, becoming more settled, more 'cooked' -- we call this 'Shu' Hua (floral) fragrance, but still not Nong Xiang, because the heavy fragrance does not last.

Medium oxidation: TGY, heavy fruity and deep floral fragrance, it lasts in the bottom of the cup. This is Nong Xiang. Roasting it will again settle the fragrance, the 'cooked' fragrance - we call it 'Shu' Guo (fruit) Xiang.

Full oxidation: Black Tea, heavy fragrance, Nong Xiang, roast or no roast.

Qing Xiang & Nong Xiang apply to all fragrances in tea, not just oolong. It is mainly determined by the amount of oxidation, not roasting, though in certain cases, roasting does appear to make it Nong Xiang, but not necessarily so.