Course:FNH200/2011w Team18 Tea

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Introduction

The finished product: A cup of green tea [1]
Leaves of Camellia sinensis (L.) O. Kuntze plant leaves before processing into green tea [2]

Next to water, tea is the most highly consumed beverage in the world. Tea is produced in three main forms with the majority of tea produced as black tea (78%), followed by green tea (20%) and finally Oolong tea (2%).[3] While black tea remains one of the most popular caffeinated beverages worldwide, green tea is gaining popularity globally. Although green tea is generally synonymous with Chinese and Japanese cultures, where the hot drink is primarily consumed, it is also a staple of some North African and Middle Eastern Countries.[3] Originally manufactured by hand in China and later in Japan, green tea is currently machine produced and exported by at least seven other countries, including Indonesia and Russia.[3] So why is green tea becoming the new trendy hot beverage worldwide? Does the tea’s current popularity have to do with new processing and storage techniques? Or is it simply a change in packaging and marketing techniques? We explore these questions by looking at the overall picture of green tea production, from the hot beverage’s history of hand processing to machine manufacturing. We also examine how packaging, storage, quality control and regulations may effect the production process.

Brief History

History of Green Tea Production in China

Tea consumption has its well-known heritages in China since around 2737 B.C.[4] The Han dynasty used tea as medicine. According to Cha Jing (Classics of Tea), which was written around 760 by Lu Yu (729-804), tea drinking was widespread during the Tang Dynasty. [5]


Steaming Process in the 8th Century (Tang Dynasty)

The steaming process was introduced during 8th Century (Tang Dynasty). The nature of the beverage and style of tea preparation was quite different from the way we experience tea today. Tea leaves were processed into cakes. The dried teacake, generally called “brick tea” was ground in a stone mortar [5]. Hot water was added to the powered teacake, or the powdered teacake was boiled in earthenware kettles then consumed as a hot beverage.


Tea Culture in the 12th Century (Song Dynasty)

Production and preparation of all tea changed during the Song Dynasty (960-1279). The tea of Song included many loose-leaf styles. Tea leaves were picked and quickly steamed to preserve their colour and fresh character. After steaming, the leaves were dried. The finished tea was then ground into fine powders that were whisked in wide bowls. The resulting beverage was highly regarded for its deep emerald colour and its rejuvenating and healthy energy[5]. Tea culture reached a high peak during Song Dynasty. The Song style of tea preparation known as the Song tea ceremony was introduced to Japan by that time.


Tea Roasting Process in the 13th Century (Ming Dynasty)

In China, steaming tea leaves was the primary process used for centuries in the preparation of brewed tea. After the transition from compressed tea to the powdered form, the production of tea for trade and distribution changed once again. The Chinese learned to process tea in a different way in the mid-13th century. Tea leaves were roasted and then crumbled rather than steamed. This is the origin of today’s loose teas and the practice of brewed tea[5].


Tea Fermentation Process in the 17th Century

In 17th Century, various types of tea plants were grown in different regions and numerous advances were made in tea production. In the southern part of China, tea leaves were sun dried and tea fermentation process was first introduced. However, this method was not common in the rest of China.[5]


Mass Production in the 18th and 19th Centuries

In late 18th and 19th Century, Chinese tea was losing its popularity in taste to Assam tea. The Chinese could not compete with mass agricultural production and rational processing methods adopted elsewhere particularly by the British in its other colonies. Therefore, mass production of tea was introduced into China by that time, especially in white tea production.[5]


History of Green Tea Production in Japan

Importing Tea Culture in the 9th Century

Green tea became a drink of the religious classes in Japan when Japanese monks travelling to China learned about its culture and brought tea to Japan in the 9th century. The first form of tea brought from China was probably in a teacake.[6]


Roasting Process Introduced to Japan in the 13th Century

The roasting process was introduced to Japan in the 13th century when southern China and Japan enjoyed much cultural exchange at that time. Teas that were processed in 13th century tasted completely distinct from these were processed before 13th since the steaming (9th century) and roasting (13th century) methods were brought to japan during two different time periods.[6]


Modern Japanese Green Tea in the 18th Century

Japanese green tea (known as Sencha) was developed in 1740. This type of tea uses dried crumbled tea leaves rather than being ground and mixed with hot water, steamed tea leaves are pressed, rolled and dried into loose tea.[6]


Machines Replace Hand Rolling in the 19th Century

At the end of the Meiji period (1868-1912), machine manufacturing of green tea was introduced and began replacing handmade tea. Machines took over the processes of primary drying, tea rolling, secondary drying, final rolling, and steaming.[6]


Automation Creates Superior Tea in the 20th Century

Automation contributed to improved quality control and reduced labor. Sensor and computer controls were introduced to machine automation. Unskilled workers can now produce superior tea without compromising the quality. Today, roasted green tea is not as common in Japan but the powdered form is often used in a ceremonial fashion.[6]

History of Green Tea Production in the Western World

Portugal was the first to export tea to the West followed by the Dutch and the English through their colonial holdings in the Far East in the middle of the sixteenth century. In 1610, the Holland United East Indian Company bought their first crop of Japanese tea in Hirado and Chinese tea in Macao from a Portuguese merchant. In 17th century, England had the exclusive right to import Chinese tea. The English preferred partially fermented green tea.[6]

Processing

Processing of the tea plant is very essential since it can determine the type of tea.[7] Variations in the methods will produce different types of tea. There are five general steps in processing the tea leaves.

Schematic representation of the processes involved to make different kinds of tea

Green tea processing machines [8]

Picking

This is done either by hand or using a machine. Buds of tea are plucked straight from the plant. A common principle in picking tea leaves is to get 2-3 leaves and one bud.[9]

Withering

The newly picked tea leaves usually contain a lot of fluid. The goal is to decrease the moisture content of the tea leaves to prevent deterioration and maintain quality.[10] The tea leaves are usually laid on a trough for several hours until they dry up and lose most of their moisture. White tea leaves stop here and do not undergo the next two steps.[7] They are dried immediately after the withering process to preserve some of their flavour, making them unique compared to other types of tea.

Rolling

This is the process of physically breaking down the tea leaves at the molecular level to free up the enzymes such as catechins which are primarily responsible for many of the health protective properties associated with tea, including anti-oxidative, anti-inflammatory, neuro-protective, anti-cancer, antimicrobial and anti-atherosclerotic properties.[11][12] Special machines called rollers press and break down the tea leaves, freeing up some of the chemicals stored in the plant.[12] There are different methods and machines to do this, but the basic goal is to crush the tea leaves to open up the hidden enzymes inside to react with the air.[12]

Fermentation

Now that the tea leaves are broken down and the enzymes are freed up, the next step is implemented. Fermentation involves the oxidation of the tea leaves. The leaves are placed in open troughs to facilitate contact with the oxygen molecules in the air.[12] This process changes the tea leaves from green to a dark brown color in about a few hours.[10] Variations in the length of time of oxidation will produce different types of tea.[7] Oolong Tea takes a shorter time to ferment than Black tea, thus having a lighter flavour.[7] Green tea does not undergo this stage, enabling it to retain the natural color and flavour by avoiding oxidation.[7]

Tea leaves being air dried on trough [13]

Drying

Drying is the last process for most tea leaves. This process halts the oxidation of enzymes by decreasing the moisture content to minimal levels of around 3%.[10] Some methods of air drying include using either a machine or the sun.[9]

Quality Control Through Blending

Once the tea leaves are processed, they are sold wholesale to tea processing plants worldwide. Brands, such as Tetley, Twinings, and Stash, have their panel of in house tea experts who can carefully blend these different wholesale tea batches, into the consistent taste and aroma with every box manufactured.[14]

Tea Blending, is the process of combing dried, processed tea leaves from many harvests to ensure consistent taste and aroma qualities. Tea blending was initially intended to mask the inconsistencies in the flavour of batches of tea [15]. Commercial tea manufactures source their tea leaves from different world wide harvesters. Every crop will yield different qualities, based on the soil content, the appearance of the batch, the structure of the leaf, the time of year it was picked, the quality of the leaf picked, and the moisture content within the dried tea leaf. Through a process of blending different tea batches, an ideal taste and aroma quality can be achieved.[14]

The Tea Blending Process

  • The tea batches are weighed to 2.68 grams per cup of tea.[14]
  • Steeping time is 5 minutes to ensure a very intense flavour. A stronger flavour will bring forth the full flavour charasteristics for easy identification.[14]
  • Once brewed, the tea is slurped to ensure exposure to oxygen in and around the tongue, mouth and gums. These are the most sensitive elements of the blender's taste perception palate. This allows identification of the quality profile of the tea batch.[14]
Blended tea [16]

Packaging

Current technology helps retain the quality and flavour of tea leaves. Factories and machines now package tea in an environment with minimal exposure to air, and seal tea inside tin cans, plastic wrap, boxes, and other materials.[17]

Tea bags

This method originated in 1908 by a New York tea importer who packaged his tea in small silk bags. His buyers would soak the entire bag in water, which they preferred over getting tea in loose form. Eventually, the method became rather popular, and in addition to silk, gauze sacks were also used.[17]

Small bits of tea leaves, called tea fannings, and tea dust are often used to fill tea bags because of their small size. As a result, fannings and dust have a greater surface area exposed to air, which may lead to quality and flavour loss. However, tea bags are commonly used today for their convenience, portability, and simplicity in brewing.[17]

Tea bags [18]

Loose tea leaves

Loose tea leaves are typically packaged in airtight or vacuum sealed containers, and are therefore able to keep its quality and flavour for longer.[17] This method of packaging allows consumers to decide on the amount of tea leaves to use for a brewing and hence, the concentration and strength of flavours. Tea pots, strainers, and infusion bags are often used so that bits of tea leaves can be separated from the drink.[17]

Instant and bottled tea

Instant tea is made by drying tea to a powdered formed by methods such as freezing, drying, spray-drying and vacuum-drying.[19] Low temperatures are used during the manufacturing process to minimize the loss of flavour. Instant tea can be turned into a drink with either cold or hot water, but are known to be lower in antioxidants.[20] Instant tea is stored in airtight containers.[19]

Bottled ready-to-drink tea originated from Japan:

  • The Pros: It is the most convenient method for consumers because no preparation is required, and allows for customization of flavours (sugar, added fruit flavours) or for adding nutrients like Vitamin C.[21]
  • The Cons: Because of more processing steps, the costs are greater. In addition, the tea is not “fresh” and natural flavour may be lacking.[21]

Storage

Tea containers protect against humidity and light [22]

It is important to store green tea in ideal conditions to keep its quality and flavour. There are several key factors to keep in mind for the storage of green tea: humidity, oxygen, temperature, light and odours.[23]

  • Humidity is the main culprit for spoiling tea during storage. With added moisture content, chlorophyll and antioxidants in the tea start to oxidize, causing the tea to degrade. To prevent moisture in the air from entering the tea leaves, the use of airtight containers is recommended.[24]
  • Another factor is oxygen. In green tea production, green tea goes through minimal oxidation to retain its natural colour and flavour, so it is best to prevent any oxidation during storage as well. An airtight container helps to prevent additional contact with oxygen.[24]
  • Temperature is another factor to consider because high temperatures increase the rate of chemical reactions and enzymes. To counter this, it is recommended that tea is stored in a cool place or even in the fridge.[24]
  • Light, like ultra-violet rays from sunlight or indoor lights, can cause an increase in temperature, changing the chemical composition of the tea. For this reason, tea should be in an opaque container stored in a location without light.[24]
  • Tea leaves are capable of absorbing odours from its surroundings. Keeping tea leaves far away from strong-smelling foods or even other teas will help it retain its own natural flavour.[24]

To summarize the storage suggestions, green tea should be kept in an dry airtight container, placed in a location that is cool, dark and dry. Tea in proper storage can last up to six months or a year without significant loss of flavour.[25] [23]

Canadian Regulations and Standards

Agriculture and Agri-Food Canada is the branch of Health Canada that oversees regulation of tea. [26] A subdivision of Agriculture and Agri-Food Canada, The Canadian Tea Industry, is primarily engaged in manufacturing of tea extracts and concentrates, including instant and freeze dried, blended and herbal tea. [26]

The Canadian Food Inspection Agency (CFIA) is responsible for monitoring and enforcement of food and drug regulations set out by Health Canada. The CFIA is also involved in the labelling and packaging regulations of the finished product. [27]

Organic Tea

According to The Canadian Tea Industry, Tea represents approximately 12% of the non-alcoholic beverages consumed in Canada and organic tea is an emerging market that is showing potential for growth.[26]

An organic product is an agricultural product that has been certified as organic. A product can be certified if it is produced using the methods outlined by the Canadian Organic Standards.[28]

The standards can be found here:

http://www.tpsgc-pwgsc.gc.ca/ongc-cgsb/programme-program/norms-standards/internet/bio-org/index-eng.html

Products that make an organic claim must be certified by a Certification Body that has been accredited, based upon the recommendation of a CFIA designated Conformity Verification Body. [28]

As of June 30, 2009, any product with an organic claim must comply with the requirements of the Organic Products Regulations: [28]

  • Only products with organic content greater than or equal to 95% may be labelled as: "Organic" or bear the organic logo.
  • Multi-ingredient products with 70-95% organic content may have the declaration: "contains x% organic ingredients." These products may not use the organic logo and/or the claim "Organic".
  • Multi-ingredient products with less than 70% organic content may only contain organic claims in the product's ingredient list. These products may not use the organic logo.

Certified organic products must also bear the name of the approval body that has certified the product as organic.[28]

Imported products must meet the requirements of the Canada Organic Regime. Should imported products bear the Canada Organic logo, the statement "Product of", immediately preceding the name of the country of origin, or the statement "Imported from", must appear in close proximity to the logo or the designations.[28]

Fair Trade Tea

Farmers and workers within the fair trade system are guaranteed a minimum price for their products and work under safe conditions. Challenges to further growth include lack of infrastructure, capacity and financing at the cooperative level, limited consumer demand in North America, and quality issues. [26]

Fairly traded tea is available at retail and, in the case of foodservice, in tea houses in Canada. There is a small but growing specialty market among consumers who are concerned about the ethics of traditional tea production and harvesting practices in developing countries. In Canada and in other developed countries, these consumers are willing to pay a premium for fairly traded products. [26]

Reflection and Conclusion

The rising trend of green tea production is due in large part to improved horticultural practices and the development of higher yielding tea plants[3]; however, improved processing, packaging and storage techniques also play an integral role in this hot drink’s popularity. For example, tea leaves were once produced only by hand, but now the majority of tea manufacturing is done by machine, from the leaf plucking, to the steaming or pan firing, as well as the rolling and air drying.[3] Furthermore, turn of the century packaging techniques, such as using silk or gauze-like tea bags has also helped the popularity of green tea globally, making the beverage more portable and convenient to prepare compared to the loose leaf varieties. Green tea may also be consumed in larger quantities due to global marketing trends that promote the beverage as beneficial to one’s health. For instance, green tea is being marketed as an antioxidant and weight loss aid.[29] It is not surprising that green tea is receiving so much attention globally, especially now that the science community has identified the beneficial antioxidant as epigallocatechin-3 gallate ( EGCG), found only in the green variety, which prevents free radicals[29]. The EGCG antioxidant is lost during the fermenting process of black and Oolong varieties[29], which may ultimately make green tea more desirable to tea drinkers but also those who are health conscious.

References

  1. ↑ Green Tea for Weight loss: Increases Metabolism and Burns Fat http://http://www.benefitsofgreen-tea.com/Green-Tea-for-Weight-loss.html Retrieved on 23 March, 2012
  2. ↑ Fusion Tea Room. Green Tea Collection http://http://www.fusiontearoom.com/Green-Tea.html Retrieved on 23 March, 2012
  3. ↑ 3.0 3.1 3.2 3.3 3.4 Graham, H. N. (1992). Green tea composition, consumption, and polyphenol chemistry. Preventive Medicine, 21, 334-350. Retrieved 8 March 2012.
  4. ↑ About.com. The history of tea-tea bags and makers http://inventors.about.com/od/tstartinventions/ss/tea.htm Retrieved on 22 March, 2012
  5. ↑ 5.0 5.1 5.2 5.3 5.4 5.5 Green tea lovers. Tea history - China (2005) http://greentealovers.com/greenteahistorychina.htm Retrieved on 22 March, 2012
  6. ↑ 6.0 6.1 6.2 6.3 6.4 6.5 Green tea lovers. Tea history - Japan (2005) http://greentealovers.com/greenteahistoryjapan.htm Retrieved on 22 March, 2012
  7. ↑ 7.0 7.1 7.2 7.3 7.4 Tea Growing and Tea Production. Wissotzky Tea (2007) http://www.wtea.com/about-tea_growth.aspx Retrieved on 20 March 2012
  8. ↑ Stir fixation green tea production line http://http://www.mycotrade.com/english/machine/production%20lines/Chaoqinglvcha/Stir%20fixation%20green%20tea%20production%20line.html Retrieved on 22 March, 2012
  9. ↑ 9.0 9.1 Processing of Sencha Green Tea. All About Green Tea. ITO EN LTD (2007) http://www.itoen.co.jp/eng/allabout_greentea/production/index.html Retrieved on 16 March 2012
  10. ↑ 10.0 10.1 10.2 Tea Production. Food-Info (2009) http://www.food-info.net/uk/products/tea/production.htm Retrieved on 15 March 2012
  11. ↑ Unachukwu, U. J., Ahmed, S., Kavalier, A., Lyles, J. T., Kennelly, E. J. (2010) White and Green Teas ( Camellia sinensis var. sinensis): Variation in Phenolic, Methylxanthine, and Antioxidant Profiles) and flavours locked inside. Journal of Food Science, 75 (6), C541-C548. Retrieved 23 March 2012.
  12. ↑ 12.0 12.1 12.2 12.3 How Tea is Produced. GreenField http://www.greenfieldtea.co.uk/e/how-tea-is-produced/ Retrieved on 16 March 2012
  13. ↑ Barenostrum. Green Tea Kakigori Shaved Ice Recipe. http://http://www.barenostrum.com/tea-machines/green-tea-kakigori-shaved-ice-recipe Retrieved on 23 March, 2012
  14. ↑ 14.0 14.1 14.2 14.3 14.4 Tea Taster. TeaGschwendner http://www.teagschwendner.com/US/en/teataster.TG?activeID=1683 Retrieved 23 March 2012
  15. ↑ Tea Era. Fusing Favours - The Art of Blending tea (2012) http://www.looseteasales.com/tea-blending Retrieved on 22 March, 2012
  16. ↑ The World of Fine Teas. The art of tea blending http://http://blog.worldoffineteas.com/2010/07/art-of-tea-blending.html
  17. ↑ 17.0 17.1 17.2 17.3 17.4 History of the Tea Bag. Learn About Tea http://www.learn-about-tea.com/tea-bag-history.html Retrieved on 22 March 2012
  18. ↑ Tips and Tricks for Puffy Eyes http://http://www.joseibi.com/tips-tricks-for-puffy-eyes/ Retrieved on 23 March, 2012
  19. ↑ 19.0 19.1 Instant Tea Plant. SSP PVT Limited http://www.foodprocessingequipments.com/instant-tea-plant.html Retrieved on 22 March 2012
  20. ↑ What is Instant Tea. eHow food http://www.ehow.com/facts_5764513_instant-tea_.html Retrieved on 22 March 2012
  21. ↑ 21.0 21.1 Food scientists pinpoint why bottled green tea is inferior to fresh brewed. Cornell Chronicle (2000) http://www.news.cornell.edu/Chronicle/00/3.30.00/ACS-green_tea.html Retrieved on 22 March 2012
  22. ↑ Art of Tea. Washi Sashi Tea Storage Tins http://http://www.artoftea.com/catalog/washi-sashi-storage-tins-p-189.html Retrieved on 23 March, 2012
  23. ↑ 23.0 23.1 Tea Storage and Packaging. In Pursuit of Tea http://www.inpursuitoftea.com/category_s/114.htm Retrieved on 22 March 2012
  24. ↑ 24.0 24.1 24.2 24.3 24.4 Green Tea Storage. Amazing Green Tea (2011) http://www.amazing-green-tea.com/green-tea-storage.html Retrieved on 22 March 2012
  25. ↑ Tea. Times Topics. The New York Times http://topics.nytimes.com/top/reference/timestopics/subjects/t/tea/index.html Retrieved on 22 March 2012
  26. ↑ 26.0 26.1 26.2 26.3 26.4 Agriculture and Agri-Food Canada. The Canadian Tea Industry (2011) http://www4.agr.gc.ca/AAFC-AAC/display-afficher.do?id=1298047470064&lang=eng Retrieved on 22 March, 2012
  27. ↑ Canadian Food Inspection Agency. Science and regulation… working together for Canadians (2010) http://www.inspection.gc.ca/english/agen/broch/broche.shtml Retrieved on 22 March, 2012
  28. ↑ 28.0 28.1 28.2 28.3 28.4 Canadian Food Inspection Agency. Canada Organic Regime: A Certified Choice (2012) http://www.inspection.gc.ca/food/organic-products/labelling-and-general-information/certified-choice/eng/1328082717777/1328082783032 Retrieved on 22 March, 2012
  29. ↑ 29.0 29.1 29.2 Health. O-Cha http://www.o-cha.com/greentea.htm Retrieved on 8 March, 2012
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