How Tea Acquires Its Goodness

The quality of tea depends on the chemical composition of the tender shoot, the raw material used in processing. The type of plant or cultivar, agricultural practices, soil type, weather and climate, combine to contribute to the chemical composition of the fresh shoot, whilst the processing method and the prevailing conditions also influence the finished product. The taste and aroma of a cup of tea is a result of all of the above.

As the influential factors vary from country to country and within each country, often from region to region, tea produced in different countries will vary in character. In countries where the influential factors are uniform throughout, the tea produced will be similarly uniform. In countries where there are distinct variations in elevation, terrain, climate and weather, Sri Lanka for example, the tea produced in each region will have its own distinctive character.

Tea in Sri Lanka is divided in to three main growing regions, Up-country, Mid-country and Low-country, based on elevation above mean sea level (AMSL). Variations within these three main regions result in the production of seven distinct types of tea known as Nuwara Eliya, Dimbula, Uva, Uda Pussellawa, Kandy, Ruhuna and Sabaragamuwa. Apart from the intrinsic and natural variability between these regions, the implementation of region-specific agricultural practices and processing methods also play a definitive role in the type of tea produced, thus contributing to a unique and diverse range not found in any other tea growing country.

Factors That Could Affect the Chemical Composition of Tender Tea Shoots

Many factors could influence the chemical composition of the fresh shoots and, ultimately, determine the quality, taste and aroma of the cup of tea so produced. A thorough knowledge of these factors enable traditional tea producers to make a high quality tea with a distinctive profile to meet a multiplicity of consumer preferences around the world.

Factors that mostly affect the quality of the final product;

• Processing method and conditions • Type of tea plant or the variety (cultivar) of tea • Agricultural practices • Climate and weather • Soil

Impact of Processing Method on Tea Quality

Processing method has a major influence on the quality of the final product. For example, all types of tea, such as Black, Green, Oolong and White teas are produced from the same raw material, which are the tender shoots of tea plant, whilst the product differentiation is achieved by the variations in processing methods. (See chapter 2 for details on types of tea).

In each of these types of tea, degree of quality is achieved through fine adjustments in the processing. For example, a longer fermentation period will result in the production of higher amounts of Thearubigins, the reddish brown flavonoid formed during black tea processing. This gives the infusion a deep reddish brown colour and produces a distinct mouth feel when tasted. On the other hand, a shorter fermentation period would yield a tea with lighter colour and a different taste.

Process adjustments employed to complement the natural character of tea are relatively easy to implement in “orthodox “processing, with Sri Lanka being best known for the wide range of high quality orthodox tea it produces. A combination of the varying climatic factors in its different tea growing regions and the fine process adjustments implemented in production, enables Sri Lanka to produce a wide range of quality tea, each representative of the region of origin.

Processing may also be adjusted according to the season or weather, to produce a tea which is “Seasonal” in character. Certain regions such as ‘Dimbulla’ and ‘Uva’ in Sri Lanka are famous for seasonal tea, produced during the dry periods in these regions, when both Relative Humidity and ambient temperatures, particularly in the night, are low. The right combination of these conditions, favour the production of precursors of volatile compounds, giving enhanced aroma to the tea. In addition to this natural improvement in aroma, adjustments such as hard wither and shorter fermentation practiced in these regions during the dry period, result in inhibiting the formation of thearubigins, leading to a lighter tea with better aroma.1

By fine tuning the processing method it is possible to make certain characters of the cup more pronounced and vice versa. Orthodox style of processing, which is followed by approximately 98% of factories in Sri Lanka, allows flexibility for such fine tuning whilst the CTC style of production, used in India and Kenya, will produce a uniform product with minimal variations. Thus, experienced ‘Tea Makers’ in Sri Lanka are able to produce tea with a variety of characteristics, to meet a wide spectrum of consumer preferences, globally.

Effect of the Type of Tea Plant on Chemical Composition

Sometimes there could be distinct variations in the same species of plant, due to inherent variations in the genetic makeup of the plant. Plants with such variations in the same species are identified as varieties. The word ‘cultivar’ is used to identify different varieties of plants which are under cultivation. Two distinct varieties or cultivars could be identified in tea. The morphology of the plant and the chemical composition of the shoots in these two types could be easily distinguished.

The relatively large and broad leaf type, originally found in Assam, India, is known as ‘Assam type’ (Camellia sinensis var. assamica) whilst the relatively small and narrow leaf type originally found in China is known as ‘China type’ (Camellia sinensis var. sinensis). Pure Assam type or the China type are rarely found in tea plantations today. Mostly hybrids of these two with more Assam or Chinese character are grown, depending on the final product planned for manufacture.2 Plants with Assam character contain more total flavonoids compared to the China variety and, therefore, are more suitable for black tea production whilst the China type is preferred for Green and Oolong tea production. The variations within cultivars permit fine adjustments in a particular type of tea.

A notable example is the planting of broad leaf Assam type in lowland Sri Lanka where a cup of reddish brown tea, with strong mouth feel is produced. As one travels up from the coastal growing regions, one finds plantations with narrower leaf producing tea of a lighter colour and lower strength; moving to the highest elevations in Nuwara Eliya, one finds plantations with narrow leaf, which produce tea , progressively lighter and with distinct aroma. By selecting the cultivar most suitable for a region, or a sub-region, a unique tea may be produced, which reflects the most beneficial impact of the conditions specific to that region.

Assam type China type

The Tea Research Institute of Sri Lanka has, since the 1960’s, been carrying out trials to breed cultivars most suited for the different regions and sub-regions. The recommendations are based on the weather and climatic factors, soil types, and likely plant disease profiles particular to that region. Suitability for manufacturing styles, which can, and will, vary from region to region, are other criteria considered in cultivar selection.

The recommended cultivar list is periodically revised with new and superior cultivars being added, subsequent to research. The current list contains 64 cultivars which have been recommended for various tea growing regions in Sri Lanka.2 Therefore, the unique combination of cultivar characteristics and other contributory factors, such as climate and weather in the specific regions, results in a variety of tea which would be difficult to replicate elsewhere in the tea growing world.

Impact of Agricultural Practices on the Quality of Tea

The agricultural practices employed would have a significant impact on the quality of the final product. Tea made from machine harvested leaf would always be inferior in quality, compared to tea from manually plucked leaf, as selective harvesting of suitable shoots cannot be achieved with machines. Due to the high cost of manual plucking many tea producing countries have either entirely, or partially, converted to machine plucking. However, certain tea producing countries such as Sri Lanka still use the traditional hand plucking that preserve the superior quality of their tea.

Generally, faster growth in the tea bush, due to over fertilization, would result in a slightly inferior tea. Therefore, ensuring adequate fertilizer with correct proportions of recommended nutrients, at the correct time, applied under the best conditions, will eventually yield the best quality tea.

Intervals between pruning is another factor that could affect the quality of the tea. Different countries adopt different pruning cycles, depending on the climate/elevation in the country or region. In Sri Lanka the pruning cycle in the cooler up-country region is four years whilst in the warmer, low-country areas, where growth rate is faster, it is three years. The rate of bush growth is faster in the first two years, slowing down gradually in the subsequent years. Therefore, the leaf produced in first two years is more suitable for the production of a coloury tea, whilst in the subsequent years, a lighter coloured tea with better aroma could be produced. Experienced managers of plantations use such knowledge to arrange harvesting to obtain the most appropriate blend of green leaf, in relation to the required character of the tea.

Effect of Climate and Weather on the Quality of Tea

Climate and weather have a significant effect on the quality of tea produced. Generally, rainy periods are conducive to vigorous growth and a correspondingly inferior tea. Extreme dry

conditions generally favour the production of increased amounts of volatile compounds in the leaf, resulting in a tea with better aroma. The general rule is that adverse climatic and weather conditions such as dry periods, warm or cold temperatures, resulting in stress conditions for the tea plant, enable the production of better quality teas. These phenomena result in the production of ‘seasonal teas’ in certain parts of the world.

Well-known ‘Dimbulla’ and ‘Uva’ seasonal teas of Sri Lanka are possible, due to the stress exerted on the bushes during dry weather in certain periods of the year. The Dimbulla region experiences the dry period from January to March or early April and in the Uva region it is from July to September. Cloudless skies, high daytime temperatures, cold nights and strong winds which desiccate the tender leaves, stimulate the production of volatile compounds in the shoot, resulting in the attractive aroma of such seasonal tea.

In Sri Lanka, one sees dramatic changes in climate, weather and vegetation, within a relatively short travel span, as from the warm, low-country coastal region to the cooler mountains of the interior. Consequently, in this small island, one finds many regions with distinctively different climate and weather patterns. This wide variation in natural conditions, the enhancement of natural advantages through the selection of cultivars, the implementation of selective agricultural practices as appropriate, and the flexibility of the Orthodox style of manufacture practiced widely in Sri Lanka, enables the production of distinct and varying types of tea, unique to each region. Sri Lanka produces three main types of tea in the low country (below 600 m AMSL), mid country (between 600 to 1200 m AMSL) and up country (above 1200m AMSL) regions. However, owing to the differences present even within these regions, Sri Lanka has the ability to produce seven distinct categories of tea known as ‘Nuwara Eliya, Dimbulla, Uva, Uda Pussellawa, Kandy, Ruhuna and Sabaragamuwa. The appearance and taste profiles of these teas vary sharply, consequent to natural factors and practices adopted by experienced planters, to complement the natural character. Similarly, plantations in the same sub-region are able to produce types of tea with subtle differences from each other, through the methods employed in both cultivation and production, assisted by small differences in natural conditions.

Effect of Soil on the Quality of Tea

Soil fertility and type could also impact cup quality, though to a lesser extent than the other influencing factors, owing to the widespread use of artificial fertilizer. Still, there are subtle differences, such as the distinctive reddishness of the “Bogo Valley” tea, attributed to the high Aluminum content in the soil of that region.

Distinct Types of ‘Ceylon Tea’

Sri Lanka has very successfully used natural advantages, enhanced by specific configuration of agricultural practices and processing methods, to augment the intrinsic quality of tea and to produce many different types of tea to meet a wide spectrum of consumer preferences, worldwide. This has been possible, largely, due to wide-ranging climatic differences in the different tea growing regions of the country.

Distinct qualities of seven major types of Ceylon tea produced in different regions are described below.

Nuwara Eliya Tea

The Nuwara Eliya region is a plateau near the summit of the central highlands of Sri Lanka. The estates in the region are situated at around1800 m (6000 ft) above mean sea level (AMSL). Mean annual temperature in the region varies between 14 to 16 degrees Celsius during different months of the year and a moderate rainfall is experienced, except from January to March, which is the dry period.3 The unique climate and the agricultural and processing practices adopted, yield a black tea which could be described as ‘delicately fragrant’.4 The infusion is lighter than all other types of ‘Ceylon tea’. This bright golden liquor with delicate flavor is highly sought after, worldwide.

Dimbulla Tea

The Dimbulla region is on the western slope of the central highlands, below the Nuwara Eliya region, and lies between 1100 - 1600 m (3500 - 5000 ft) AMSL. This region is wet and misty during most parts of the year, as the western slopes directly meet the Southwest monsoon between May and September, enhanced by frequent inter-monsoonal rains.

Dimbulla also benefits from the cool, dry winds of the ‘Dimbulla quality season’ that begin in January and continue until March or early April, during which a fine golden-orange coloured, refreshingly mellow cup with a delicate aroma, the Dimbulla seasonal tea, is produced in the region. Variations in topography within the region result in different micro-climates, which yield a spectrum of tea with varying quality characteristics, especially aroma.

Uva Tea

The Uva region lies on the eastern slopes of the central highland, south east of Nuwara Eliya. Though this region experiences both Northeast and Southwest monsoon systems, the weather is relatively dry. Winds in the region are usually dry, as rains in lower elevations remove the moisture. Therefore, a change of weather lasting a few days can have a noticeable impact on the quality of tea, most pronounced during the ‘Uva quality season,’ from July to September, resulting in the world famous ‘Uva seasonal teas’. The infusions are reddish brown during wet periods, but change to a lighter golden orange hue during the dry season. The exquisite aroma produced in the seasonal teas

attract the attention of connoisseurs of tea, world over.

Uda Pussellawa Tea

The Uda Pussellawa region, a relatively small area wedged between Nuwara Eliya and Uva, is located on the eastern slope of the central highlands, below the Nuwara Eliya plateau. Elevations in Uda Pussellawa range from 950m to 1600m (3000 - 5000 ft).

Uda Pussellawa climatic conditions are sharply different from the western slope of the central highland. As with neighbouring Uva, the region receives the bulk of its rain from the northeast monsoon system between November and January. The climate is mostly wet and misty. However, the region also experiences dry conditions between June and September, when the southwest monsoonal winds, having deposited rain on the western slopes of the hill country, sweep across Uda Pussellawa. Thus, this region has two quality seasons, from January to March and again from July to September.

Uda Pussellawa teas are described as ‘exquisitely tangy’ with the liquor, of a pinkish hue, being darker and stronger than the neighbouring Nuwara Eliya tea. Colder conditions at the end of the year add a hint of rose to the bouquet of the tea, known for its medium body and subtle character.

Kandy (or Mid Country) Tea

Kandy lies north of the Nuwara Eliya region and being significantly lower than the southern segment, the region is classified as ‘mid country tea’ (or mid-grown), the elevation ranging from 650 m to 1300 m (2000 - 4000 ft).

Mostly the rains are due to the southwest monsoon. The teas produced in the region are stronger and deeper-coloured than those from higher elevations and are described as strong and full bodied.

Ruhuna Tea

The Ruhuna tea-growing region lies in the Southern part of the island of Sri Lanka and the terrain consists of coastal plains, with low hills towards the interior, within the ‘wet zone’ of Sri Lanka, receiving its rain mostly from the southwest monsoon. The altitude is 600 - 0 m (2000 - 0 ft) AMSL, thus the teas are also referred to as ‘Low country (or low grown) tea’. The higher temperatures result in a relatively faster growth of the bush than in the higher elevations.

The cultivars in the region have a pronounced Assam character (broad leaf) and these, combined with highly region specific climatic factors and processing methods, produce a strong and deep reddish brown infusion with a unique flavour. Generally, the Ruhuna teas have a wider variety of grades than in higher elevations and the particle sizes are also relatively larger. Teas with ‘tips’ (tip of the buds) are highly sought after grades of Ruhuna teas.

Sabaragamuwa Tea

The Sabaragamuwa region, like Ruhuna, lies in the low country region of the wet zone of Sri Lanka. However most of the estates lie higher than those of Ruhuna, and range from sea level up to around 800 m (2500 ft). The rains to the region are brought about by the south west monsoon. As the region lies between the coast and the central highlands the monsoon blowing inland from the sea brings heavy rains to the region.

The infusion is similar to that of Ruhuna teas, dark yellow-brown with a reddish tint. However, the aroma is different from the Ruhuna tea, with a hint of sweet caramel. Sabaragamuwa teas are described as ‘exceptionally stylish’.

• Quality of the tea is mostly determined by the chemical composition of the shoot plucked for processing. Chemical composition of the fresh shoot is mostly affected by the type of tea plant or cultivar, agricultural practices, climate/weather and soil conditions. Further, processing conditions also influence the character of the final product. • Tea produced in each country is different from the tea originated in other countries.

Within tea growing regions of a country also, climatic and weather conditions could significantly vary resulting in many distinct types of tea. Sri Lanka is a good example with distinct types of high quality tea as climate and weather significantly varies between the tea growing regions. The Orthodox style of processing used in Sri Lanka permits further enhancement of the natural character of the tea. • Sri Lanka produces three main types of tea;

Up country, Mid country and Low country depending on the elevation. Within these main regions also differences exist, resulting in seven distinct types of tea called Nuwara

Eliya, Dimbulla, Uva, Uda Pussellawa, Kandy,

Ruhuna and Sabaragamuwa.

REFERENCES

1. R.L. Wickramasinghe, 1978, Facets of tea research in practice, Monograph 7, Tea Research Institute of Sri Lanka. 2. Gunasekare M T K, 2012, Tea plant (Camellia sinensis L.) breeding in Sri Lanka, In: Global Tea Breeding: Achievements, Challenges and Perspectives, (Ed. Liang Chen, Zeno Apostolides, Zong-Mao Chen), Springer-Verlag Berlin Heidelberg, pp125-176. 3. Climate of Sri Lanka, Department of Meteorology, Sri Lanka, available at www.meteo.gov.lk/index.php?option=com_content&view =article&id=94:climate-of-sri-lanka&catid=20&lang=en&Itemid=310 accessed on 30th November 2016. 4. Tea growing regions, Sri Lanka Tea Board. Available at www.pureceylontea.com/index.php/features/the-importance-of-origin, accessed on 27th March 2017