When looking for a caffeine jolt, should one turn to coffee or tea? Some may tell you coffee has more caffeine than tea, and some may say the tea contains more caffeine than coffee. Believe everyone! They are both right! Gram per gram, tea leaves contain more caffeine than coffee beans, (Tea leaves contain about 3.5% caffeine, coffee beans contain 1.1% to 2.2% caffeine - Arabica 1.1% and Robusta 2.2%). Liter per liter however, brewed coffee contains more caffeine than brewed tea. This occurs because tea is properly made with about 15grams leaves per liter water, and for coffee about 50grams beans per liter water.