Tea leaves contain a lot of tannic acid, theophylline, tea sesame oil and multiple vitamins. It is more suitable to brew with boiling water at about 80 degrees Celsius. If you use a vacuum flask to soak the tea in high temperature water for a long time, it will be like decoction with a low fire , It will destroy all the vitamins in the tea, and the tea sesame oil will also volatilize in a large amount; tannic acid and theophylline will be leached out in a large amount. This not only reduces the nutritional value of tea, but also loses the fragrance of tea and increases harmful substances.
