In the meantime, lower altitudes have more insects, resulting in more concentrated caffeine. The caffeine content also depends on more familiar factors, such as: One 8-oz serving size of brewed coffee ...
Here's a breakdown for reference. An average, 12-ounce can of soda contains 30 to 40 mg of caffeine. An 8-ounce cup of green or black tea contains somewhere between 30 to 50 mg of caffeine (green tea ...