There is much controversy surrounding caffeine and its effects. Taken in moderation, caffeine increases alertness, reviving the spirits of the tea drinker. However, caffeine has also been claimed to be a substance of abuse, with many people addicted to an early morning jolt, particularly from coffee. It is not surprising that heavy users of caffeine are also associated with other unhealthy practices, such as excessive smoking and poor diets.
Tea contains caffeine.
Per pound of tea leaf, tea contains more caffeine than coffee per pound of bean, but because more ground coffee is typically used to brew a cup of coffee than tea is used for a cuppa, the average cup of tea contains less caffeine than the average cup of coffee. Caffeine does have a slight bitter taste distinct from the mouth-drying, puckery taste of tea, known as astringency, but one cannot generally tell the amount of caffeine based on the taste of the brew. Caffeine contents in tea depend on the method or style of brewing, the type of tea, and the temperature of the water. Contrary to popular opinion, green tea does not necessarily contain less caffeine than black tea, although because green tea leaves are generally larger-leaf teas and from var. Sinensis Chinese shrubs, they will sometimes produce a beverage which has lower amounts of caffeine than black teas, typically produced from var.