Your tea is totally chemical! And this is normal

Green tea comes from the leaves of the same plant as black tea does. They become different after they are harvested, and human intervention determines what the drink will be like.

Original photo [Depositphotos]

Green tea comes from the leaves of the same plant as black tea does. They be­come dif­fer­ent af­ter they are har­vest­ed, and hu­man in­ter­ven­tion de­ter­mines what the drink will be like. Tea con­sists of the dried leaves and buds of the plant Camel­lia sinen­sis. Polyphe­nols con­sti­tute up to 40% of the mass of a tea leaf. The oth­er 60% is made up of amino acids, pro­teins and methylx­an­thines (for ex­am­ple caf­feine), vi­ta­mins and non-or­gan­ic sub­stances. Tea also con­tains trace amounts of volatile or­gan­ic sub­stances. They have a strong in­flu­ence on the fla­vor and aro­ma of the drink.

Many volatile or­gan­ic sub­stances that de­ter­mine the aro­ma of tea only arise in the course of en­zymic ox­i­da­tion. This is the stage of treat­ing the leaves which de­ter­mines whether the tea will be black or green. Slight­ly dried tea leaves are placed in a room with a con­trolled cli­mate for a cer­tain time. The polyphe­nols con­tained in the tea leaf are ox­i­dized by the oxy­gen in the air in the pres­ence of spe­cial en­zymes – ox­i­das­es. Two of these polyphe­nols – epi­gal­lo­cat­e­chin and epi­gal­lo­cat­e­chin gal­late (the most pow­er­ful an­tiox­i­dants in tea) trans­form into thearu­bi­gins. These sub­stances also have an­tiox­i­dant prop­er­ties. And they also give black tea its red­dish col­or.

Green tea [Depositphotos]

This means that the col­or of the tea de­pends on the length of en­zymic ox­i­da­tion. For ex­am­ple, tea that is in­tend­ed to be green is bare­ly ox­i­dized at all. Al­most im­me­di­ate­ly af­ter the leaves are picked, they are treat­ed with a jet of steam va­por, or some­times sim­ply heat­ed in a pan. The high tem­per­a­tures de­ac­ti­vate the ox­i­das­es. White tea is in sec­ond place by its de­gree of ox­i­da­tion. It gets its name from the ap­pear­ance of the tea bud, which is thick­ly coat­ed with white fluff.

In third place is yel­low tea. This rare sort is made from the finest leaves, and only in Chi­na. It is made in a very sim­i­lar way to green tea, but with an ad­di­tion­al step: the leaves are treat­ed with steam un­der a wet fab­ric. This process is what makes them yel­low.

Next in the rat­ings comes oo­long tea. To make oo­long tea, fer­men­ta­tion is not car­ried out com­plete­ly, and the en­tire tea leaf is not ox­i­dized, only the edges and part of the sur­face. Nev­er­the­less, ide­al­ly about half of the leaf should be ox­i­dized. It is thought that oo­long com­bines the prop­er­ties of green tea (a strik­ing aro­ma) and black tea (a rich fla­vor).

To make black tea, leaves are ox­i­dized by tra­di­tion­al tech­nol­o­gy from two weeks to one month. In Chi­na, this tea is called red (af­ter the col­or of the drink), while the Eu­ro­pean name came from the col­or of the leaves be­fore they are brewed.

And fi­nal­ly, the most fer­ment­ed tea is pu’er. It is in­ten­tion­al­ly aged, to give it a char­ac­ter­is­tic earthy taste. There are sev­er­al ways of do­ing this. One method is to gath­er the tea leaves in a bunch, sprin­kle them with wa­ter, and cov­er them with a cloth. Some mold fun­gi are also in­volved in the treat­ment process. The process of pre­par­ing qual­i­ty pu’er tea lasts at least a year. This sort of tea is called black tea by the Chi­nese.

Pu-erh [Depositphotos]

Syn­thet­ic reagents or sol­vents are not used in the man­u­fac­ture of tea. The only sec­ondary prod­ucts of ox­i­da­tion are wa­ter and car­bon diox­ide. So tea can be con­sid­ered to be the purest prod­uct of all the ones that we con­sume.

Be­sides its treat­ment, the taste and aro­ma of tea de­pends on the place where it grows. For ex­am­ple, in Chi­na the sub­species of the tea plant Camel­lia sinen­sis sinen­sis grows, which prefers high al­ti­tudes and rel­a­tive­ly low tem­per­a­tures. The plant from the In­di­an state of As­sam be­longs to the sub­species Camel­lia sinen­sis as­sam­i­ca. It grows in val­leys, at high tem­per­a­tures and in high hu­mid­i­ty. All of this af­fects its chem­i­cal com­po­si­tion. As­sam tea is con­sid­ered to have a tarter and harsh­er fla­vor than tea made from the leaves of Camel­lia sinen­sis sinen­sis.


A cup of tea

The chem­i­cal com­po­si­tion of treat­ed tea leaves also de­pends on whether the leaves are knead­ed (mac­er­at­ed) by hand or ma­chine. The pur­pose of the process is to de­stroy the cel­lu­lar struc­ture in­side the leaves and pro­vide greater con­tact of polyphe­nols, ox­i­das­es and oxy­gen. There are two types of mac­er­a­tion: tra­di­tion­al, when peo­ple rub the leaves man­u­al­ly on bam­boo trays or in bas­kets, and me­chan­i­cal, when the tea leaves are rolled, crum­pled and torn by spe­cial equip­ment. In the sec­ond case the cel­lu­lar walls are de­stroyed less del­i­cate­ly, and the dam­age is much greater, Ox­i­da­tion takes place more ac­tive­ly. As a re­sult, tea made of leaves that are treat­ed man­u­al­ly is more aro­mat­ic but lighter in col­or, while tea that is treat­ed me­chan­i­cal­ly is strong­ly col­ored, but has a weak­er aro­ma. Of course, me­chan­i­cal­ly treat­ed tea is cheap­er, while man­u­al­ly treat­ed tea is con­sid­ered to be of high-qual­i­ty, and is ac­cord­ing­ly more ex­pen­sive.

Tea bags are some­times filled with so-called screen­ings (very fine par­ti­cles of tea leaves), or even tea pow­der – the finest and cheap­est sort of tea. Al­though this pow­der gives a cup of tea a good col­or (and also the cup it­self), it usu­al­ly doesn’t stand out for its fla­vor and aro­ma.


Tea with cream

Adding milk to tea re­duces its health prop­er­ties. The pro­teins con­tained in milk, ca­seins, form com­pounds with the polyphe­nols of tea, mak­ing them dif­fi­cult to di­gest. But at least the milk cools the tea down. And let’s ad­mit it: we like this mix­ture of tan­nins, methylx­an­thines and ox­i­dized polyphe­nols most of all for its taste, while its health ben­e­fits take sec­ond place.