The amount of caffeine in tea can vary greatly – everything from the time of harvest, the variety of tea bush cultivated, the amount of tea used in brewing, the length of infusion and the quality of the water all play a role in how much can be extracted from the leaf.
There isn’t a dramatic difference in caffeine content between the different types of tea (white, green, black, etc). Below is the range of caffeine that each type generally has?
Black Tea: 25-110 mg in 5 oz of water
Green Tea: 16-60 mg in 5 oz of water
White Tea: 12-50 mg in 4 oz of water
Herbal Tea: 0 mg naturally decaf