Ancient Iranian used to drink coffee instead of tea. That is why the tea shops were called coffee shop of course in Farsi language. In 1901 King of Iran ordered the Deceased Kashef Ol Saltane the Council of Iran in India to learn how to plant, produce tea and to get familiar with different techniques of tea production. Kashe Ol Saltane was the first person to plant and produce black tea in Iran.
According to Iran National Standard Quality of tea is determined by taste and appearance. The experienced Panelists taste result is often the acceptable result by individual.
The taster’s judgment who has the credentials from one of the formal tea taster organization is valid.
Chemical and pesticide analysis is tested on all kind of teas. The ISIRI has introduced the specific factors for a good tea.
It is often thought the oil stain on the pot or cup, is coming from the water using for brewing tea. So after referring to documents and facts the following result has derived from the tea producers.
The Tannin and caffeine in the tea is a strong stimulant which increases alertness, energy and concentration in one. When tea gets cold and its temperature decreases to less than 17 degrees, tannin and caffeine in the tea react AND the new element as Tanat caffeine appears which also produces Poly fennel THAT cannot be oxidized.
Tanat Caffeine which is a kind of residue, appears as hanging particles and makes the color of tea dull. Non Oxide poly fennels also appears as free round oil stains on the surface of tea and sticks around the cup.
Dark color tea or Dull color tea
It has been shown in the water analysis that more hardness in water the duller the brewed tea and the more alkaline solution in water the darker brewed tea will be. Zinc is one of the nutritional elements which is absorbed by food ingredients. The normal amount in the surface water is 0.1 and in the underground water is 0.5mg per liter. Zinc might exceed in the old galvanized pipes. If Zinc exceeds more than 4mg per liter (zinc sulfate) the water will have an unpleasant taste of acrid. This component can cause oil stains and milky color on the boiling water if is about 3 to 5 mg per liter.
The World Health Organization, has suggested the allowed concentration of zinc in drinking water is up to 3mg per liter, which then you can have a good and tasty tea.