What’s the Difference Between Green and Black Tea?

Tea the most popular beverage. 

Tea is the most widely consumed beverage in the world next to water. Of all types of tea consumed, Ceylon black tea, produced in Sri Lanka, is considered the best tea in the world and the most popular. Sri Lanka green tea is not far behind. Green tea has been gaining popularity over the years and becoming the second most consumed type of tea worldwide. 

So, what’s the difference between the two? 

On a physical and sensual level, black and green teas appear different from each other in color, odor and taste which are unique to each tea, based on manufacture

 

Black Tea is the result of a lengthy process that includes Withering, Rolling, Fermentation, Firing (drying), Grading and Packing. 

A good leaf standard of tender shoots of 2-3 leaves and bud is sine qua non for production of high quality teas. 

The first step in back tea manufacture is Withering. It was, at one time, erroneously believed thst the sole purpose of withering was to reduce moisture content and produce a leaf which was sufficiently limp for Rolling. It is now known that several biochemical changes of great importance occur during withering. The majority of these changes is completed in 6-10 hours and it may therefore be true that the prolongation of the wither beyond this period is necessary mainly for the loss of moisture and concentration of the polyphenols and the polyphenoloxidase to facilitate Fermentation. Among the many important biochemical changes which occur during withering are:

  1. Increase in polyphenoloxidase activity for Fermentation.
  2. Breakdown of proteins to amino acids and these amino acids are important for the development of colour, flavour and bouquet of tea liquors.
  3. The breakdown of Chlorophyll, which progresses during the subsequent stages.
  4. Increase in caffeine, which is important for physiological activity (health) of tea.
  5. Increase in simple carbohydrates e.g glucose.
  6. Breakdown of carotenoids important for flavour and play a decisive role in he valuation of a tea.

Rolling

Certainly the loss of moisture makes the leaf sufficiently limp, which helps rolling. It helps to give the twist to the leaf particles, which in turn improves the made tea appearance. Also, some of the biochemical and chemical  changes initiated during withering, continue during preconditioning and proceed at an accelerated rate during rolling. The maceration that takes place during rolling helps to breakdown the leaf particles, and bring the substrate- the polyphenols present in the inner palisade layer come in contact with the enzyme- polyphenoloxidase present in the epidermal layer, thereby facilitating fermentation.

Fermentation

 

The principal reaction that occur during fermentation is the reaction between the polyphenols and the polyphenoloxidase (enzyme). The oxidation of the unoxidiced polyphenols is brought about by the enzyme polyphenoloxidase in the presence of oxygen (air). The theaflavins produced have antioxidant properties accounting for the health benefits of tea and are also known to provide the full development of aroma and flavour. They undergo polymerization to give the thearubigins that would provide colour and strength to the brew. 

Firing or drying

Firing arrests fermentation by denaturing (killing) the enzymes and helps to reduce the moisture of the tea to 3%, which helps the keepability of tea. Further, the flavour of the tea is 'balanced' during firing because some of the lesser desirable low boiling compounds are removed thus accentuating the presence of the more useful higher boiling compounds. 

Grading and packing

Grading is the process of separating the fired tea into particles of different sizes by the use of mechanically oscillated sieves fitted with mesh of various sizes. The grade is defined, on the one hand, by the mesh size of the sieve through which the tea passes, and on the other, by the size on which it is retained. This grade specification is entirely artificial to meet buyer requirements. The various grades are stored in air tight bins until a sufficiene quantity has accumulated to pack an invoiuce.

Green Tea

The first step in the manufacture of green tea is the heat destruction of the enzyme polyphenoloxidase by steaming (Japan) or pan firing (China). The leaf is thereafter semi dried, rolled, fired graded and packed as in black tea manufacture.

The primary difference between black tea and green tea is that the former contains a mixture of native unoxidiced polyphenols, together with the theaflavins and the oxidiced/polymerized thearubigins whereas green tea contains only the unoxidiced polyphenols. It was at one time assumed that green tea has more antioxidant properties (health benefits) than black tea. However, the theaflavins produced during fermentation is now known to be having more antioxidant properties than the unoxidiced polyphenols, as such both black tea and green tea is known to have the same health benefits.

What some don’t know however is that both black and green tea comes from the same plant Camellia sinensis.

Which is better for you, green tea or black tea?

For centuries, tea has been known for its medicinal properties. Its caloric value is very low as it contains minute amounts of carbohydrates, protein and fat.

 But tea is mostly known for its antioxidant value. The tea plant is rich in antioxidant flavonoids that have the ability to limit damage caused to our bodies. Antioxidants have been found to reduce risks of non-communicable diseases such as heart disease, stroke and diabetes where the development of the disease is associated with inflammation. Both black and green tea contains higher levels of antioxidants compared with other food items. 

Up until recently it was believed that green tea was the most effective antioxidant-containing tea and that green-tea catechins (the unoxidized polyphenols present in tea leaf) alone were the antioxidants giving tea its health-giving attributes. But this view has changed. Research has shown that the theaflavins and thearubigins produced by the condensation of oxidized catechins, during the fermentation stage of black tea manufacture, are equally effective antioxidants (Leung et al 2001). 

Oxidation during black tea processing only changes the color and flavor of the tea. It doesn’t make any difference to the amounts of antioxidants and minerals found in either tea. Both green and black teas are equally healthy for any tea lover.

Does green tea or back tea taste better?

Depending on where tea is grown, tea will take its own unique strengths, colors and tastes.  The climate, the soil, the water level and other conditions affect the quality of the tea plant and its resulting tea shoots.

The difference of processing black tea and green tea makes each tea different in chemical composition which in return gives their distinctive tastes. The conversion of catechins to theaflavins and thearubigins during oxidation is the main reason for the change in taste.

Black tea is generally sweeter than green tea, as the transition accentuated by the drying process brings out the sweetness in the tea leaf. By retaining the original flavor and chemical composition of the camellia leaf, green tea gives a fresher, leafy and natural taste.

Is black tea hard on your stomach? 

Tea, as in the case of most beverages contain caffeine, which speeds up bowel movements. A cup or serving of tea (180 ml) is said to contain approximately 60 mg of caffeine as against 100 mg in 180 ml of coffee (Ashihara et al 1997). Caffeine stimulates gastric secretions. In active peptic ulcer patients coffee produced a sustained elevation of gastric acid secretion (rise was only transitory in normal subjects), but tea has no such problem.