Thin film that forms on the surface of strong brewed tea, according to the sign of a good quality of the drink, the measure of stiffness and water pollution.
To date, unambiguous answer the origin of the film on the tea, there is - there are several versions explaining its origin.
Experts advise to pay attention to externalfilm look. Uniform color plaque or tiny specks in it suggests that the cause of formation of the film has become too hard tap water. The high content of calcium carbonate in water when combined with organic substances contained in tea, causes the film. If you add a slice of lemon in a drink or a drop of lemon juice, the film disappears.
There is also a view that the film formation reason - the oxidation of iron contained in water.
Rainbow in a cup
The thin iridescent film, homogeneous and easilycrashing while stirring the beverage formed essential oils and tannins contained in tea and give it a unique flavor and tart taste. If tea is brewed for a while will stand untouched, oils and tannins are oxidized - the result of oxidation and becomes iridescent film on the surface of the liquid. The stronger the tea, so it will be more noticeable.
Another cause of brownish filmAccording to specialists - oxidation of mineral and organic compounds, including caffeine and catechins contained in tea are exposed to oxygen in the air. The composition of this film is very difficult - it includes protein compounds, purines, tannins, iron, calcium and other substances and compounds.
Harmful or helpful?
The views of experts on the impact of tea on the filmhealth diverge. On the one hand, it is an indication of a high content of mineral oils, on the other - forms an insoluble coating, which when consumed regularly brewed tea is firmly deposited on the mucosa of the stomach and intestine, inhibit the absorption of nutrients.
It is found that the worst effect onhealth human use of long-standing tea - after brewing black tea should drink for a few hours, in any case, leaving the tea leaves for the night. Thereafter the beverage loses useful properties, increased content of harmful substances in it, including toxic guanidine benign formed by oxidation of guanine contained in tea.
High concentrations of guanidine are extremely dangerous, and for the emergence of symptoms of poisoning is enough to drink a few cups of strong tea leaves yesterday.
On the walls of the cups of poorly formed filmwashable plaque, get rid of which sometimes does not help, even washed in a dishwasher. If the tap water in your area contains a lot of calcium, magnesium and iron, it is better to get a special filter or use tea pure drinking bottled water. Do not forget that distilled water is too hard, does not bear any good body.