Types of tea-Introduction
- 1.1) Tea plant
- 1.2) ♦ Conventional Tea products:
- 1.3) ♦ Non- conventional tea products:
- 1.4) ♦ Convenience Tea products:
- 1.5) ♦ Trending tea products:
- 1.6) Conventional Tea products
- 1.7) Black Tea
- 1.8) Green Tea
- 1.9) Yellow Tea
- 1.10) Red Tea
- 1.11) Dark Tea
- 1.12) White Tea
- 1.13) Non-Conventional Tea products
- 1.14) Instant tea:
- 1.15) Flavored Teas:
- 1.16) Decaffeinated Tea:
- 1.17) Conclusion
Types of tea-Introduction
Before reviewing the types of tea, let us see some basics.
TEA: Tea is one of the widely consumed ancient beverage in the world.
Tea is an aromatic beverage made by mixing boiled water with leaves of Camellia sinensis (the botanical name for tea). Various types of tea are available all around the world.
People prefer drinking different types of tea as it gives a refreshing feel to the body and the mind.
Due to its caffeine content, a sense of excitement arises in the body, which makes the body awake and active for a relatively longer time than before.
People in South Asian countries like India are very fond of tea. In another way, it can be said that they are addicted to it. People often drink tea a minimum of twice a day in India.
This addiction in most people is such that they feel a mild headache if they miss a tea for a day.
Tea consumption originated in China and reached European continents in the 16th century.
In the 19th century, tea cultivation started in Assam, India.
So, two basic varieties from ancient times are-
- Chinese variety (C.S. sinensis)
- Assamese variety (C.S. assamica)
The tea plant grows to height 35 feet in tropical and subtropical climates.
These plantations are carried out at altitudes at 2460m above the sea level. For the easiness of plucking, bushes are maintained at a certain height.
Different types of tea are-
- White Tea
- Green Tea
- Oolong Tea
- Black Tea
- Pu’erh Tea
These different types of Tea vary in color, smell, taste, appearance, etc.
Now let us see different types of products made from Tea.
♦ Conventional Tea products:
a. Completely fermented Black tea
b. Un-fermented green tea
c. Partially fermented Oolong tea
♦ Non- conventional tea products:
a. Cold and hot soluble instant tea
b. Flavoured-tea and decaffeinated tea
Some other recent tea products that have gained tremendous demand in the global market are among Convenience tea products and Trending Tea products-
♦ Convenience Tea products:
a. Canned or bottled tea
b. Soluble tea mixes
c. Frozen tea liquid
d. Tea tablets
♦ Trending tea products:
a. Liquid tea concentrates
b. Tea mixes
c. Iced tea mixes
d. Fruit tea mixes
Conventional Tea products
Black Tea improves cholesterol levels, decreases blood pressure, and improves gut health.
The main steps for processing black tea are-
Step-1: Harvesting and plucking
Tender and uniform terminal bud and two shooting leaves or only shoots with 3 leaves are picked from the tea plant twice a year.
Usually, manual picking is done for high-quality tea, but it is costly. So, mechanical picking is also an option.
Mechanical picking gives increased quantities of broken types of tea leaves and other partial tea leaves.
Other types of tea leaves are Coarse leaves. These are not plucked due to its interference with the quality of the tea.
Withering means removal of moisture from the tea leaves. The sap cells in the tea leaves also become concentrated due to this withering process.
There are two methods of Withering:
- Natural Withering- Here the freshly picked tea leaves are spread out in thin layers on wire meshed racks that are arranged in one above the other. Then further drying in natural air for a minimum period of 20-24 hours is allowed.
- Artificial Withering- The plucked tea leaves are widely laid in layers of a width of 18-20cm layers in tables with wire meshes that are placed in tunneling which forced circulation of warm air mixed with fresh air takes place.
Step-3: Breaking Up
Breaking up is a general process of rolling the weathered leaves which is a pre-preparation step.
The breaking up is done by using a circular table having a circular cone with a lateral slat like arrangement called Battens.
A circular jacket along with a pressure cap is attached to the top of the table.
Step-4: CTC Method for tea leaves (Crushing, Tearing & Curling)
CTC method has 2 metal rollers separated but placed with a minimum distance between each other revolving at unequal speeds.
Due to this revolution of the metal rollers, the weathered and broken up tea leaves are torn, cut, and get twisted. Hence, the juice which comes out from the tea leaves due to pressing initiates the fermentation process by Oxidation.
The oxidation process that started during rolling is continued. The fermentation process occurs in separate fermentation rooms that are cleaned thoroughly to prevent the microbial contamination of the types of tea.
Theses tea leaves are layered off in 3.5 to 7.5cm Aluminium trays.
The thickness of the Aluminium trays for layering the types of tea leaves are decided on the basis of fluctuations in the room temperature.
When the tea acquires Copper red color, the process of fermentation is stopped as the correct degree of fermentation is reached. Since we know that tannin is also a component of Tea, it decreases during the fermentation process.
We observe pleasant aroma in different types of tea. This aroma formation is mainly due to the oxidation of amino acids, unsaturated lipids, or carotenoids, etc. during the fermentation process.
Step-6: Drying or Frying
Drying is done on a 4-plate system drier.
Hot air at around 90°C is blown against the leaves, whose temperature reduces till 80°C after the drying process.
Due to this drying process,
- the Polyphenol PPO enzyme properly get inactivated
- the moisture content reduces to 3.5%
- the pleasant aroma is established
- the tea leaves take their typical black coloration
Step-7: Grading and Storage of Fermented tea
Winnowing is done to separate the stalky matter and grading is done by sieving so that the different types of tea grades are obtained on the basis of particle size analysis.
The tea is stored in Oxygen and moisture-proof areas to prevent any loss of flavor and aroma that is developed during the fermentation process. Under such tight and secure conditions of storage, up to 1-year shelf life of the black fermented tea is possible.
For green tea production, a bud and 2-3 leaves of tea shrubs are harvested. Green tea has a large number of catechins and vitamins along with pleasant taste, aroma, and a light olive green shade color.
Green tea is unfermented and the inactivation of the browning enzyme is considered a crucial factor. If the green tea leaves are roasted in a pan, then the enzymes are surely inactivated.
The processing steps for green tea leaves are-
Plucking > Steaming/Roasting > Primary heating & rolling > Rolling > Secondary rolling > Drying > Refining> Firing > Sorting > Packaging
Yellow tea is very much similar to green tea. The variety of yellow tea is unfermented and is brighter in color than green tea.
The taste noted for the yellow tea is milder as compared to green tea and is highly refreshing and having darker aroma relatively. Yellow tea contains a higher amount of catechins and vitamins as compared to Black tea.
For the production of Yellow tea, one bud and two or 3 young leaves and tender tea plant shoots are used.
The weathering process should be performed carefully and informally right from the tender parts of the shoots, the bud then from the first leaf to the third leaf and stalk.
The main steps used in the manufacturing of yellow tea re Withering >roasting >rolling > sorting > firing.
Red Tea is a less fermented tea having delayed enzymatic reaction along with the chemical process. Generally, the red tea has a mild tea and a stimulating aroma.
The Common steps in the manufacture of Red tea are-
Withering > Rolling > Roasting > Firing > Sorting > Final Firing
Dark Tea is an unfermented tea traded only in the Chinese internal market.
It is called Dark tea because of its brownish-yellow or brownish-red color, which is obtained after the Infusion. Dark tea is such a type of tea giving milk aroma but is highly vulnerable to the fermentation by microbes.
1 bud leaf of dark tea has around 4-6 leaves united with stalks are subjected to Withering and rolling followed by Piling > Drying > Steaming and finally compressing to obtain the Dark tea.
White tea is a type of fermented Chinese tea which is manufactured only for export purpose. However, on infusion, the white tea gives orange-yellowish tea when infused.
The process of withering and firing is very selective in the manufacture of such a type of tea, i.e. the White tea.
So, a bud having one or two leaves with intense hairs or buds having moderate content of polyphenol can only undergo the process of Withering and firing.
Due to the withering process for white tea for almost 3 days, the amino acid content increases along with the decrease in the levels of polyphenolic content and sugars.
Non-Conventional Tea products
Some famous non-conventional tea products are Instant tea and Flavoured teas, decaffeinated teas, etc.
Instant tea is a highly hygroscopic product which is obtained by dehydrating the infusions of either black tea or green tea.
The raw materials required for instant tea preparation are Black tea, green tea, low-grade tea, dust tea waste, crude tea leaves, etc.
The preparation process is a step-wise manner is given-
Extraction > Decreaming and Cream Solubilization > Aroma Stripping and Aromatization > Concentration > Drying > Chemical Composition > Blending.
Flavored tea is widely consumed around the world. They are produced by the incorporation of various natural and nature-like flavors in the processed teas.
For example, teas spiced with cardamom, ginger, cinnamon, clove, or essence teas like lemon-essence teas, orange, rose, or mint-flavored types of tea. Fruity flavored teas are also added to the teas like the essence of apple, raisin, banana, fig, etc. are also widely consumed.
Other examples of flavored teas are- Flavored green tea, flavored-oolong tea, flavored-decaffeinated tea, etc.
The flavor is sometimes imparted to the teas manually by placing alternate layers of tea leaves and fragrant flowers into stacks. So, natural flavors are transferred to the tea leaves.
The stack is heated almost for 2 hours to make it crisp. After drying, the stacks, the crisp tea leaves are separated with sieves.
For packing purpose, these flavored/ scented teas are mixed with the unscented teas in a ratio of 1:20.
Decaffeinated tea is mostly preferred by people who have some health concerns on drinking caffeinated teas.
These decaffeinated teas are made by removing almost 60-90% of the caffeine content from the black teas by the process of Solvent extraction.
The conclusion about the types of teas is discussed below in points-
1. Physical properties of tea leaves
The processed tea leaves do not have fibers, stalks, and other foreign matters. The Grading of teas is done as leaf grade, brokers, innings, and dust based on the particle sizes, color, and other infusion qualities.
2. Chemical properties of tea leaves
The tea’s quality can be assessed by the chemical substances’ presence like polyphenols for e.g., caffeine, tannins, theaflavins [TFs], pectins, and thearubigins [TRs], sugars, noncaffeine nitrogenous compounds, lipids, and minerals.
3. Sensory qualities of tea leaves
The major sensory qualities for assessing the final brew’s goodness are quality, color, strength, flavors, briskness, etc.
4. Packaging and storage of tea leaves
Black tea leaves are stored for around 300 days, which leads to the flavor retention at a relative humidity of around 32% at 20°C.
To say it finally, tea is among one of the top beverage consumed in many countries, and different people prefer different types of tea as per their choice and taste.
However, the food technologists and scientists are continuously aiming to develop new products to serve the growing demands of tea lover consumers.