Vacuum bottle are mostly adopt sealed type for heat preservation,due to the structure of the tea itself,can be fermented in airtight case,after fermentation of the tea will produce some harmful substances to human body.Tea is rich in protein,fat,sugar,vitamins and minerals and other nutrients,is a kind of natural health drink,containing tea polyphenols,caffeine,tannins,tea pigment and so on,and has many pharmacological effects.Tea leaves in hot water for a long time,like temperature decocting,tea polyphenol and tannin substances such as a large number of leaching,make tea color thick,with an indication.

Vitamin C and other nutrients in the water temperature exceeds 80℃ will be destroyed,high temperature and soaked for a long time will make its loss too much,which reduces the tea health care function.

At the same time,due to always maintain a high water temperature, the aromatic oil in tea can quickly a large number of volatile, tannic acid,theophylline,a large number of seepage,this not only reduces the nutritional value of tea,reduced the tea, also makes harmful substances.