All their flavor is quickly dispersed. Decaffeinating tea bags is less effective because the tannins release almost as quickly as the caffeine. The only way to tell is to taste it. Don't rely on the color unless you are familiar with a specific tea. There are some general guidelines for steeping tea, but, in the end, personal preference should be your guide.
Tea has a wide range of caffeine depending upon the type of tea, plant varietal, and brewing style.
By comparison, a typical cup of coffee has roughly 125-185 milligrams of caffeine. They are then separated during the day. This process is repeated several times. This is the one flavored tea in which high qualities of both tea and jasmine are occasionally used to create a wonderful beverage. There are no agreed-upon standards for organic farming in Asia.