The Story of Tea

by Mary Lou Heiss

  Oolongs tend to derive from varietal plantings. Fujian is the historical source of oolong tea because the subspecies of the Camellia sinensis plants that produce the finest oolong teas grow there. Fujian and Taiwan both have the terroir and shared plantings that best support the growth of first-quality oolong tea plants, both wild and under cultivation. The tea artisans who manufacture this outstanding tea lavish special attention on their tea.

  There are many styles of oolong tea and different methods for brewing them. In general, they are very easy drinking and fun to experiment with. They can also be fussed over; the choice is yours. For a genuine oolong-tea-drinking experience, find someone who can perform a gong fu tea ceremony for you, together with several friends (see “Gong Fu Tea Service” in chapter 7). This unique oolong brewing ritual has, like all fine rituals, its own set of utensils and teawares and is based on historical tea-brewing methods.

  True gong fu service is altogether elegant and somewhat messy (Fujian Province, China).

  SOUTH ASIAN OOLONG?

  During the 1990s the expertise required to manufacture oolong tea was introduced to other tea-growing regions, most ambitiously in Darjeeling and Sri Lanka. What will the future be for these non-Chinese oolongs? The soil is not correct, the climate is different, and the plants are young and not of the subvarieties considered appropriate for the manufacture of fine oolong. The bushes may be in venerable old tea gardens, but there is no local tea tradition for the production or appreciation of oolong tea. It is difficult to imagine that these new-growth teas will be able to compete with the snap and verve of Chinese or Taiwanese oolongs (see “Oolong Teas” in chapter 4).

  WORLDWIDE INTEREST IN SUBVARIETALS

  On our most recent tea-sourcing trip to Fujian and Japan, we discovered that the tea artisans in Fujian are noting renewed interest in the older, more traditional styles of oolong firing: the darker, more exotically pungent styles that they prefer and believe to be more historically “proper.” This old-style firing is increasingly popular (again) in Southeast Asia, Hong Kong, Canada, and Japan. The gardens in Fujian are also producing much leaf, and experimentation is ongoing to try to make interesting black tea and green tea from the leaf of specific, older varietals such as Tieguanyin and Rou Gui. In Japan we discovered that oolong is the craze of the moment, and enthusiasm for oolong has spread to the gardens there, where oolong varietals (particularly Tieguanyin) are being planted to see whether or not Fujian’s oolong sub-varieties will grow (and produce quality leaf) in Japan. The flavor profiles of these varietals are so unique that if these trials yield quality drinking tea, tea enthusiasts everywhere are in for a treat!

  Black Tea (Qi Hong or Red Tea)

  The most popular class of tea outside of Asia is the second most popular tea in the world. This incredible leaf is known today as black tea. The Chinese, in their early color-based system of identifying tea by the color of the brewed liquor and not the leaf, identified this class of tea as red tea. This allowed their term black tea to be used to designate the deeply dark-brewing liquor of the only truly fermented tea: the highly regarded pu-erh (see the discussion on “Pu-erh Tea” later in this chapter).

  BLACK TEA, DEFINED

  Black tea is not fermented, it is oxidized; The most common error found in discussing or describing black tea is the improper use of the terms fermented and fermentation as a phase in the production of this class of tea. One can distinguish between those who are simply repeating information that they have read or heard and those few who have truly taken the time to learn about tea, understand the differences among the great classes of tea, and then be specific about the processes involved in the different manufactures. If you visit a teashop or website and there is any mention of “fermentation” in reference to the production of black tea, run—do not walk—to another tea vendor!

  Complete oxidation creates this truly remarkable class of tea. In the production of black tea, the critical component necessary to effect an even and complete oxidation of the “made tea” (finished leaf) is the “juice” trapped naturally inside the leaf structure. How this juice is allowed to release from its native holding cells and the controlled chemical reactions that follow are the processes that make the manufacture of black tea so interesting. An even wither (when required) and the best general results will always be had using either a budset or a fine pluck—the premium pickings from the new growth on the bush. A coarse pluck will contain less moisture but will have a harder epidermis (skin), so more time and careful supervision may be required to wither it successfully. One of the most important factors in a successful wither is the uniformity of the leaf that has been plucked.

  A proper wither requires that the leaf within each batch be consistent in size, as withering a quantity of leaf that is heterogeneous is a fool’s game. A fine pluck is always the first choice for initiating high-quality tea, because when a pluck is picked uniformly it does not require sorting, which inevitably adds another handling to the leaf, which increases both the cost and the time of the overall process. Thus some argue that the pluck is the single most important element of black tea manufacture.

  WITHERING: PREPARATION IS EVERYTHING

  The primary drying step in black tea production is called withering, the beginning stage of the time-consuming and complicated process of the manufacture of black tea. Withering consists of two distinct phases: physical withering and chemical withering. These are involved and complex processes that condition the leaf for the processes that follow. Some tea experts argue that withering is the single most important step in black tea manufacture.

  The sections of a traditional tea factory where withering takes place are known as the withering loft. They are large, enclosed, but well-ventilated spaces with good natural air circulation that is often supplemented by powerful ceiling fans. If leaves are processed during the rainy season, when the leaf is first introduced to the loft heaters are used for short periods to help drive excess surface moisture from the leaf. If the weather is particularly humid, heaters may be fired up briefly even during withering to aid evaporation. Ideally the ambient air should be sufficient, so tea factories are situated at high elevations or in open locations. The physical wither sets the stage for successful tea processing; it creates the foundation leaf on which all the subsequent processes depend.

  Physical withering. The initial drying stage of the withering process is known as physical withering (the reduction of moisture). The sole function of physical withering is to make the fresh leaf pliable and prepared to develop further during the numerous processing steps that follow. There is too much intrinsic moisture in a freshly picked Camellia sinensis leaf than will allow that leaf to be twisted without breaking, so the 70 to 77 percent innate moisture content of fresh leaf must be reduced to a more manageable 60 to 65 percent. Only after this portion of its native moisture has been driven out can the leaf be twisted and bruised during the rolling process, the motion that spreads the internal juices over the entirety of the surface of the leaf, thereby facilitating proper oxidation.

  Chemical withering. Only through comprehensive withering is the leaf able to yield a quality finished tea. While physical withering is the process that encourages superior oxidization, chemical withering sets in motion the biochemical changes necessary for good cupping quality. As the moisture content of leaf undergoing physical withering reaches that desirable level of 60 to 65 percent, chemical withering begins spontaneously. Then the final 10 to 20 percent of withering is the chemical withering (the conversion of the juices inside a leaf’s cells into more complex liquoring compounds).

  Natural withering. Traditional natural withering is known as open (chung) withering. This simple form of withering is accomplished by spreading a several-inch-thick layer of freshly plucked leaf on what are known as “tats”—trays made of tightly stretched jute hessian (a type of burlap) or occasionally wire or synthetic mesh. The tats are banked vertically in columns, separated by 4½ to 6 inches (12 to 15 centimeters) of airsp
ace. Air circulates through the leaf, driving off both the heat that is generated by the drying process and the evaporating moisture. Natural withering normally takes eighteen to twenty hours and is considered to be the finest form of withering, the method that most likely yields premium tea. Natural withering is most often used when manufacturing premium large-leaf orthodox tea that will command a high price in the marketplace. In Sri Lanka, for instance, many old tea factories have central fans and intake/exhaust systems in the withering lofts that draw fresh dry air from the ground up through the leaf that is withering on vertically stacked tats or in open-top withering troughs.

  Trough withering. The most widespread style of withering today is accomplished by the method known as trough withering. These troughs may be open-top or enclosed. An open-top withering trough is a wooden box, commonly 6 feet wide (1.8 meters) and 75 to 100 feet long (23 to 30 meters), rising 2 to 2½ feet (0.6 meters) off the floor. The box has sixteen-gauge wire mesh mounted horizontally throughout, which actually creates the trough. This withering trough is literally a plenum chamber within the box, into which the fresh leaf (8 to 10 inches deep, or 20 to 25 centimeters) is placed. The plenum chamber is a finite space between two controllable openings or vents, the purpose of which is to redirect or manage the volume of the air flowing between. The most modern versions of these plenum chambers are within boxes that are double-wide or wider (12 to 15 feet, or 3.7 to 4.5 meters) and of considerably varying lengths (60 to 120 feet, or 18 to 36 meters).

  All sizes of open-top withering troughs typically have fans mounted in the ends of the lower part of the box, below the leaf. These fans are often variable-speed and reversible, and are used prudently to create a current of air that rises through the leaf. This upward current of air can affect uneven withering of the leaf, causing the bottom leaf to wither faster than the upper leaf. Methods of regulating this include reversing the airflow of the fans and turning the leaf during the wither. Turning the leaf is practically difficult when using double-wide troughs and not preferred when processing orthodox leaf, as it may break a significant number of leaves.

  For the manufacture of orthodox leaf, tats, traditional single-wide open-top troughs, and small enclosed troughs are most often used. Open-top troughs are generally filled to the top of the box, so that as the leaf becomes flaccid, it shrinks to just below the top edge of the side boards. If fans are used, they are engaged sparingly, and the flow is reversed on a regular basis. Whether on tats or in open-top troughs, the leaf being prepared for orthodox tea is fluffed one or two times, very gently. If heat is incorporated into the air stream, it is applied cautiously, only during the early wither, to prevent the leaf from over-drying prematurely.

  Withering troughs at Parkside Estate (Nilgiri, India). Photo courtesy of Eliot Jordan.

  If leaf for cut-tear-curl (CTC) production is being withered in open-top troughs, the side boards of the box normally rise above the fresh leaf by several inches, to support the necessary turning of the leaf that occurs once or twice during the withering period for CTC leaf. Fans are commonly used, so the combination of the increase in airflow and the greater exposure of the surface area to evaporation due to the turning make the process go more quickly (only sixteen to eighteen hours).

  The newest form of withering trough is the enclosed trough, which is similar in function to an open-top trough, except that the airspace above the plenum chamber is boxed in, mimicking the airspace below. The advantage of this type of trough is that the air current can be maintained at a more even flow and pressure. The trough is situated in the box such that the airspace below the trough is equal to or slightly less than the airspace above the top of the leaf. Fans are mounted on one end and are one-directional, blowing into the box. There is a baffle just inside the fan end that controls whether the airflow goes up through the leaf from under the plenum or goes down through the leaf from the airspace above the plenum. The exit doors for the spent air are placed on the opposite end and are shuttered so that they can be toggled: one open while the other is closed, drawing the blown air through the trough. Because the airflow continues in the same direction for the entirety of the process, pressure builds up in the enclosed trough and the evaporation rate becomes optimal. Turning the leaf is eliminated, as the change in direction of the airflow accomplishes the same result without the damaging physical movement of the leaf.

  When withering leaf for CTC manufacture, the enclosed trough becomes an integral part of the more modern, faster manufacture of a greater quantity of leaf tea. Many modifications are currently being researched and implemented to increase the quality and efficiency of the enclosed trough method of withering. Given that energy availability and costs are a constant problem in tea-producing regions, much work is being done to maintain the quality of traditionally withered leaf while simultaneously decreasing energy use. For example, one 5 HP fan running continuously for twelve hours consumes 44,760 watts (5 × 746 × 12 = 44,760). Check your electric bill to see what your per kilowatt charge is, then do the math to determine just one of the many costs that go into the base price of your cup of tea!

  An important consideration regarding the modernization of the withering process is that for withering to be complete, both physical withering and chemical withering must happen. Chemical withering will only occur if the withering process continues for a minimum of nine to twelve hours for most CTC tea, and sixteen hours for orthodox tea. Using modern withering equipment, physical withering may reduce the moisture content of the leaf to the desired level well before chemical withering has initiated the internal biochemical changes necessary for a great finished tea. When chemical withering is complete, a distinctive fruity aroma releases from the leaf, the result of the internal breakdown of proteins and carbohydrates into simple sugars and amino acids. While this chemical change is taking place, the concentration of caffeine and polyphenols is increasing. A simple rule of thumb is that the better the wither, the more successful the oxidation will be.

  THE PROCESSING OF BLACK TEA

  The actual processing of black tea divides into two styles: orthodox and cut-tear-curl or crush-tear-curl (CTC). Orthodox black teas are those that we otherwise call whole-leaf tea. They are graded by size, and the nomenclature varies by country. Orthodox teas are recognized as being of the highest quality, and are the teas of legend, commanding a fair price and representing the skill of the tea artisan. Black teas are graded in a different way than are the other classes of tea, and within the orthodox style, this sieve size is an important factor in the eventual pedigree (see the individual country listings here, here, and here in chapter 4 for specific grade designations).

  THE ROLLING PROCESS

  Withered leaf destined to become orthodox black tea now goes through the rolling process. Following a quick but thorough sifting to sort the leaf into uniform-sized particles, rolling twists, compresses, and turns the leaf over and over. This distorts the leaf and bursts its cellular structure, releasing internally what some call “juice.” This rolling action encourages the internal enzymes and polyphenols to mix, setting in motion the enzymic oxidation of the catechins that eventually feed the oxidation process, turning this withered leaf into tasty black tea.

  Originally manipulated by hand, by loosely squeezing and wringing bunched piles of tea, or rolling and pressing mounds of tea on a tabletop or woven mat, this process has evolved into one requiring sophisticated machinery that replicates these movements without unnecessarily ripping or tearing the whole leaf.

  In the mid-1800s withered leaf was first mechanically rolled in Java, in a machine created by a man named A. Holle. Mechanical rollers were introduced to tea manufacture in Assam in 1872 by William Jackson, at Jorhat, and their use has spread worldwide. Although minor modifications have been made to the equipment and materials have changed, the technique is essentially unchanged since that time. Brass rollers integrated into freestanding platforms that have raised surfaces to generate the necessary folding movement have replaced primitive cast
-steel units that were formerly hand-held over a wooden table. This machine is known as a planetary roller.

  During rolling for orthodox tea, only internal injury to the cell structure of the leaf is desired; the leaf is not chopped into pieces as is required in rolling CTC teas. A secondary step that may be combined with orthodox rolling is the use of a machine called the Rotorvane. Developed in 1957 by Ian McTear of the Experimental Tea Research Station at Tocklai in Assam, this machine is a motorized tumbler/barrel/drum with a diameter that ranges from 8 to 18 inches. It has a central shaft that acts as an auger, pulling the leaf through the drum. Leaf processed through a Rotorvane is thoroughly distorted, crushed, and mixed, generating heat and furthering the enzymic activity.

  This manipulation also spreads the juice to the leaf’s surface so that oxidation can begin. Some Rotorvanes are open on the far end, allowing the leaf to exit reasonably whole. This type of Rotorvane is used when making the so-called broken grades of orthodox leaf. A Rotorvane is not used at all in the manufacture of whole- or large-leaf black tea grades, as the process would break the leaves.

  ROLL-BREAKING AND SIFTING

  For superior oxidation to occur, rolled leaf must be cool, aerated, of a uniform particle size, and evenly coated with the enzymatic juice. Because the release of the enzymatic juice during the rolling process causes the leaf to start to bunch and clump the next step is roll-breaking and sifting. By breaking up the clumping masses of leaf back into individual rolled leaf, this intermediate step aerates the clumps, reduces the temperature of the leaf, and does a preliminary sieving. This process also helps to evenly coat the leaf with the enzymatic juices, ensuring that superior oxidation can take place.