<P> Tea contains more caffeine than coffee by dry weight . A typical serving, however, contains much less, since tea is normally brewed more weakly than coffee . Also contributing to caffeine content are growing conditions, processing techniques, and other variables . Thus, teas contain varying amounts of caffeine . </P> <P> Tea contains small amounts of theobromine and slightly higher levels of theophylline than coffee . Preparation and many other factors have a significant impact on tea, and color is a very poor indicator of caffeine content . Teas like the pale Japanese green tea, gyokuro, for example, contain far more caffeine than much darker teas like lapsang souchong, which has very little . </P> <P> Caffeine is also a common ingredient of soft drinks, such as cola, originally prepared from kola nuts . Soft drinks typically contain 0 to 55 milligrams of caffeine per 12 ounce serving . By contrast, energy drinks, such as Red Bull, can start at 80 milligrams of caffeine per serving . The caffeine in these drinks either originates from the ingredients used or is an additive derived from the product of decaffeination or from chemical synthesis . Guarana, a prime ingredient of energy drinks, contains large amounts of caffeine with small amounts of theobromine and theophylline in a naturally occurring slow - release excipient . </P> <Ul> <Li> Mate is a drink popular in many parts of South America . Its preparation consists of filling a gourd with the leaves of the South American holly yerba mate, pouring hot but not boiling water over the leaves, and drinking with a straw, the bombilla, which acts as a filter so as to draw only the liquid and not the yerba leaves . </Li> <Li> Guaraná seeds ("beans") are used in making the commercially sold beverage Guaraná Antarctica, which originated in Brazil and is currently the fifteenth most popular soft drink in the world . </Li> <Li> The leaves of Ilex guayusa, the Ecuadorian holly tree, are placed in boiling water to make a guayusa tea, which is both brewed locally and sold commercially throughout the world . </Li> </Ul>

Where does caffeine come from in energy drinks