Basics of Tea Manufacture
Published : 21 Aug, 2020

“Sometimes there’s not a better way. Sometimes there’s only the hard way.” – Mary E. Pearson, The Fox Inheritance

This article is not for those who want to learn Tea Processing in detail but to make our readers get a basic understanding of the differemnt stages of tea manufacture and the roles played by different factory machinery in the industry.

Tea Processing or Manufacture – from harvested green leaf is a long and complicated process in order to produce Green tea or Black tea. Processing is generally in the same manner in all factories, except certain technical aspects of manufacture differ depending on elevation and climatic conditions which prevail in the area a factory is located.

Manufacture is carried out where the personnel are very well experienced and qualified to carry out the most important tasks in producing an end product which must be to an acceptable standard at the international level. Otherwise, the tea can get rejected or fetch extremely low prices culminating in total loss to the producer.

Power Generation

Like in any other industry, tea manufacture too needs power energy for its various stages of operation. I still recollect the constant rumbling noise of the old tea factory in my birth place, ringing in my ears. In the early days of Ceylon Tea, it was either a National Engine supplied and serviced by Walkers or a Ruston Hornsby Engine, supplied and serviced by Brown & Co. Ltd., for factories’ power production.
These engines were used during peak load period, i.e., during manufacture when most of the Rolling room, Firing room and Sifting room machinery were in use. Also, during low load period, i.e. only during Withering and Sifting, the Pelton/Turbine would be used where this facility was available. If a Dynamo was run by the Engine or Pelton the Direct Current (DC) electricity that was produced was used for lighting of the Factory and Bungalows. If an Alternator was connected the alternate current produced (A.C.) was used. When Engines and Pelton/Turbine were used, these were connected to overhead steel shafts with a series of different size Pulleys and Belts to run the machinery. At present almost all factories run with electricity supplied by the Government, Ceylon Electricity Board (CEB). With CEB power all machinery are run by Motors and the Shafts and the use of engines has become obsolete.

Some factories also have Pelton/Turbine in use which is connected to an Alternator and used during low load period and for lighting. Most factories also have Stand-by Engines coupled to Alternators to produce electricity to run Motors during power interruptions.

Below is a picture of Ruston Engine manufactured in England (Ceylon Tea Museum)

The following are basic information on tea manufacture which our readers may find interesting.

Withering – Tehn and Now!

There are two types of withering equipment used, the old Hessian or Nylon Tats and modern Withering Troughs. Use of Hessian or Nylon Tats for withering is time consuming and takes up much more space than Troughs. To the best of my knowledge, presently, no factory uses Tats for withering.

Below: Jute/Nylon Tats, which have become obsolete (Pic from Ceylon Tea Museum)

  • The process of Withering is carefully monitored, as over-withering can seriously affect the end product. During withering physical and chemical changes takes place in the leaf. A correct level of withering is achieved taking into consideration external factors such as humidity, temperature and standard of leaf. A very good standard of green leaf is really important for the tea manufacturing process to achieve a high standard of quality tea.
  • Both Black Tea and Green Tea is made out of the same tea bush – “Camellia Sinensis.” In Black Tea, the green leaf is withered for several hours to reduce the moisture content and rolled to break them into Dhools. This process starts a series of chemical reaction that are catalysed by the enzymes in the leaf. In the Fermentation stage, the enzyme which has been brought out from the leaf cells during rolling starts a reaction when exposed to oxygen in the atmosphere and results in it loosing the harsh astringent character to mellow the taste and acquire colour and flavour in the liquor.
  • In the case of Green Tea manufacture, the green leaves are subjected to heat by steaming or putting in a heated pan to reduce the moisture. This avoids fermentation or the oxidization stage, which in turn inactivates the enzymes. It has been found that over 300 types of amino acids are present in Black Tea or Green Tea (preserved under this process), and said to be extremely beneficial to human health. In Green Tea Manufacture the green leaf is exposed to a high temperature either by a steaming process or Panning process thereby destroying the enzymes. When the enzymes are destroyed the juice extracted is not oxidized (fermented) thereby the liquor will not have much colour but retains a different flavour and taste.
  • The first process after the green leaf arrives at a factory is Weighing as it is. The next stage is called Withering.

(Pics of a modern withering equipment – Troughs)

The importance of transporting the plucked leaf to the factory cannot be emphasized more. That is why they have at least three ‘weighing’ of leaf in the field. The leaf received at the factory is quickly weighed and then spread evenly on tats or troughs. They are stretched the whole length on the upper floors where there is free air flow, so that excess moisture is removed from the leaf.

Most, if not all, tea factories in Sri Lanka now use Troughs for withering. They replaced earlier methods of withering leaf on tats made of jute hessian, which were mostly imported from Bangladesh.

When the correct level of withering has been achieved, the leaf is rolled, twisted and slowly broken up. During this process, the leaf is ruptured causing the air to come into contact with the cells triggering a chemical reaction.

Rolling

According to Ferguson’s Ceylon Directory, “the first tea rolling machine was made in Ceylon by John Walker & Co., in June 1880.” I could not find a picture of this machine in any factories I visited, though finally I found this “Little Giant” at the Ceylon Tea Museum, Kandy, which is said to be the first Roller to be installed in Ceylon.

Orthodox rolling is the most common method, where the green leaf is rolled in Rollers. This method produces the traditional looking, long and wiry whole leaf types. This method of rolling is achieved by feeding withered leaf into a machine which appears like a large mixing bowl, on a circular, hard-surfaced table, on which brass or wooden battens, and a brass or wooden cone is fitted in the centre. During the process the leaf is torn apart to a certain degree and also crushed. Orthodox teas tend to be lighter and less full bodied, compared to CTC manufactured teas.

During the Rolling process, leaf is twisted, torn apart to a certain degree and crushed under pressure and broken up into small particles which are coated with the juice that is being extracted.

Rollers occupy the ground floor of the factory and the withered leaf is fed through openings on the ceiling into the roller cylinder. This cylinder is adjustable to give the required pressure on the leaf during rolling. The pressure cap on the Cylinder or Jacket as it is commonly called can be lowered on the leaf inside Jacket to give the required pressure on the leaf during rolling.

Orthodox teas tend to give lighter liquor and less strength, compared to CTC manufactured teas.
Cut, Twist & Curl (CTC).

In the CTC manufacture process, the withered leaf is conditioned in a Roller or Rotorvane and then sent through a series of CTC machines, either three or four in a row. Withered leaf passes through two large rollers that revolve opposite to one another. On each roller are a multitude of sharp teeth milled and set at an angle that mesh with the opposing roller. As the tea passes through the two CTC rollers they are crushed, torn and twisted and broken into very small particles. Due to this action the leaf breaks down into very small, grain like particles. This method of processing is popular for higher yields of crop. CTC teas are more suitable for ‘tea bags’ since they brew quickly and give out good liquoring tea with a small quantity of tea ( normally 2 grams in a bag).

Fermenting or Oxidation

The rolled leaves, now called Dhools, are collected and spread over Fermenting Tables, or sent through fermenting machines where exposure to warm air makes it ‘fermented.’ During Fermentation, the tea acquires its quality, flavour, strength and colour depending on the fermenting period, amount of juice coated on leaf particles, humidity and temperature. The period can vary from twenty minutes to five hours. Due to the chemical process, the leaf changes from greenish to a bright coppery colour.

The fermented leaf is then sent through the firing chambers where hot air will quickly dry the Dhools to prevent further chemical reaction taking place and the tea acquires the black appearance.

Firing or Drying

Firing technology itself is highly technical, as the process involves firing temperature, volume of air, load of leaf on to dryer trays, period of drying and the inlet and exhaust temperatures. The machinery used for firing is called a Drier. There are different types and sizes of Driers in use.

Endless Chain Pressure Drier

Once the tea passes through the firing process, it will be ready for Grading. The Graded Tea is the final product. The tea particles are separated into different shapes and sizes, by sifting through a progressively finer series of meshes. The various grades denote only the size and appearance of the leaf and bear no relation to the quality or flavor.

(Below picture of a Stalk Extractor produced by P.P.P. Jinadasa (Pvt) Ltd., widely used in tea factories.)

Tea Tasting and Analysis of Finished Product

Tea Tasting is a very skilled part in the process of Tea Manufacture, marketing and valuation. It is a skill which is gained through considerable experience and is an important part of the commercial aspect of tea by which the worthiness of a particular tea is assessed and valued.

Tasting is initially carried out by the Factory Manager and Estate Manager at the factory which produces it. It is later carried out by trained professionals at the Tea Brokers and Buyers offices and these professionals are called TEA TASTERS.

This important segment of tea trade requires a broad knowledge of the quality, market trends, grades, appearance, taste and aroma of the finished product. The assessment process is generally termed Tea Tasting in the tea industry.

Made tea is infused in hot or cold water depending on the type of tea you need to assess, i.e. Green Tea, Black Tea etc. Tea Tasting is generally carried out without milk, but blenders add milk to see how the tea takes it. A good tea with milk shows an amber colour as opposed to greying dull colour given by poor tea.

The following points are usually looked at while tasting tea:

  • Appearance
  • Colour of infused tea
  • Taste of infused tea

Packing and Marketing – End Product

(Above: An old Tea Weighing Machine on display at Pedro Tea Boutique)

Once Grading is complete the Teas are weighed and packed into Tea Chests or Paper Sacks ready for dispatch.

Packed Tea has to be converted to money. Storage and Marketing comes into place at this stage, bearing in mind the following:

  • Tea has a shelf life that varies with storage conditions and type of tea. Black tea has a longer shelf life than green tea.
  • Several changes occur during the storage of tea before marketing takes place, some chemical and others biological. These commence shortly after the tea has been fired and are beneficial during the first few weeks of storage but detrimental thereafter. Before marketing, prolonged storage causes loss of Theaflavin, amino acids, sugars, pigments and other valuable properties which determine flavor and quality of the tea.
  • Tea stays freshest when stored in a dry, cool, dark place in an air-tight container. However, development of rancidity is most rapid in ultra-dry conditions, whereas browning reactions occur in moist conditions and micro organisms thrive in very moist conditions.
  • Black tea stored in a bag inside a sealed opaque canister may keep for two years.
  • Green tea loses its freshness more quickly, usually in less than a year.
  • Storage life for all teas can be extended by using desiccant packets or oxygen absorbing packets, and by vacuum sealing.
  • When storing green tea, discreet use of refrigeration or freezing is recommended. In particular, drinkers need to take precautions against temperature variation.
  • Improperly stored tea may lose flavor, acquire disagreeable flavors or odours from other foods, or become moldy. Marketing of such teas could become a problem subsequently.

The Tea once packed will have its own ‘Mark.’ This may be either the name of the factory which produced it or any other name registered with the Brokers for this purpose. A single factory can use more than one mark.

Colombo Tea Auction is the most important place for Sri Lanka’s tea marketing. When a ‘Lot’ is ready on the estate consisting one or more grades with sufficient quantity to meet a sale, the manager draws from the bulk two sets of samples. One set is sent to the Agents who manage the estate and the other to the selling Brokers in Colombo for tasting and reporting in preparation for marketing.

Tea Samples and Catalogues

  • Three weeks ahead of the actual sale date all teas ready and offered for sale by estates are catalogued. Samples from each lot are made available to the registered traders along with a printed copy of the Broker’s Catalogue two weeks prior to the sale date.
  • During the quality season, the demand for tea increases. Some buyers call for samples earlier for onward transmission to their overseas buyers during this period.
  • For Main Sale teas, a three-kilo sample is drawn from three packed tea chests chosen at random by the Broker’s representative, by boring a hole on the side of the chest. The opening is then sealed with a metal cover.
  • For Ex Estate Sales, samples are taken out before the tea is finally packed from three different chests. Chests from which samples were taken will be clearly marked “S” to denote this fact. These samples are sent to the Brokers for sampling. The samples are distributed among various buyers either in tins provided by prospective registered buyers or wrapped in special paper.

At this stage teas are tasked for valuations by the Brokers. Their reports on taste and valuations are placed on each ‘Lot’ , which gives a guide to the prices that could be expected when the ‘Lot’ comes up for sale.

In the meantime, the buyers themselves taste and evaluate samples received and make their decision on prices to be paid, based on demand, credit availability, and market trends. The buyers then fix a price in keeping with their requirements on each ‘Lot’ they are interested in buying in the Main Sale Auction.

In the case of Ex Estate Sales, upon instructions from the Brokers, the tea will be dispatched directly from the estate to the buyer who purchased the tea.

If the tea brokers find bids to be unsatisfactory, they withdraw the particular ‘Lot’ from the sale. The withdrawn teas are either sold as out-lots after the Sale or re-catalogued for a subsequent sale.

The Buyer is obliged to settle the cost to the Broker within a week from the auction date. Once the settlement is done, the buyer gets a Delivery Order to obtain his purchase from the Seller’s Stores for Main Sale Teas.

In summary the following methods are commonly adopted for Made Tea Sales.

  • On estate called “Tea Centres” and this is becoming popular especially among foreign tourists, if the estate is close to a main road or an area popularly visited by them.
  • Public Auctions – sold by auction at the Colombo Tea Auction organized by the Colombo Tea Traders Association, usually held weekly. The auction is open to all registered tea dealers, the majority of whom are members of the Colombo Tea Traders Association as well.
  • All tea sales are in accordance with a set of laws formulated by the Sri Lanka Tea Board.
  • Private Sales – Tea is also sold thru Private Sales at a price mutually agreed by a Panel of Tea Tasters.
  • Ex Estate Sales – Teas which are not included in Main Sales are sold in this method.
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The ‘Lion Logo’

In order to ensure consumers identify “Pure Ceylon Tea” in packs which indicate so, the Sri Lanka Tea Board has initiated a Lion Logo to appear on Ceylon Tea packs denoting the country of origin and quality of the product. The Sri Lanka Tea Board owns the Logo, which has been registered in over 75 countries.

The Board has laid out certain conditions for the use of Lion Logo on Ceylon Tea brands packed in Sri Lanka:

  • The logo can be used only on consumer packs, which contain 100% Pure Ceylon Tea.
  • The brands should be packed in Sri Lanka.
  • The brands, which use the Lion Logo, should conform to the quality standards set out by the Sri Lanka Tea Board.

Therefore, teas packed outside Sri Lanka cannot use this Logo, even if the packs contain the purest item. Next time when you buy any brand claiming to be Pure Ceylon Tea, look for the Lion Logo on the pack to make sure you have the right product. (Source: Sri Lanka Tea Board).

(Below) Some Standards set for tea factories:

(Below) Brown & Davidson Advertisement in early 1900s.

Anver Kamiss

Tuan Branudeen Kamiss writes with the pen name ‘Anver Kamiss’ was born on an upcountry tea plantation in the Dickoya Tea Planting district and completed his senior secondary education at Highlands College, Hatton. He was the first expatriate to complete 23 years of continuous service on a United States Air Force contract in the Sultanate of Oman as the Senior Administrative Officer. Anver Kamiss had a previous life! He served for over 18 years in Sri Lanka’s lush tea plantations in the Dickoya and Dimbula planting regions, his final tint at Drayton Kotagala in the Dimbula planting region, where he was in-charge of the plantation office. His passion for Ceylon Tea never diminished, upon his return made him switch to extensive research on some of Sri Lanka’s best Tea Factories in the Upcountry area. His book was purchased by one of Sri Lanka’s top Tea Exporters – Akbar Brothers five years ago. Anver Kamiss has settled in Canada and will be contributing a series of articles on the life of Tea Estate people, Factories and Machinery, all of which go to produce what the world recognizes as CEYLON TEA! Any questions on the subject may be directed to him by email [email protected]

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