Are You Caffeinated Enough? How Much is in Your Favorite Brews?

Fuel for the engine of progress or a riotous corrupter of society? Debates over caffeine have brewed throughout history. Caffeine is the most abundant stimulant in the world, found in a variety of plants (tea, coffee, kola, cocao,…). The majority of the world consumes it in one form or another, but what forms are the most potent and how much is to much enough?

25 to 50 milligrams of caffeine is all the average human requires to begin feeling the effects, but that’s just slight alertness. It takes the average healthy human 45 minutes to metabolize caffeine and has a half-life of approximately 5 hours. In the excess, 9 mg/kg (~4mg/lb) has been shown to increase endurance by 51% (ref). X-ray vision comes around 50mg/kg.

Death by coffee is close to impossible which may surprise you when a single strong cup can give you the jitters. Here’s some Math for you: A healthy adult requires roughly 150-200mg/kg (~91mg/lb) of caffeine for a lethal dose. There is an average of 13mg/oz of caffeine in drip coffee. So if I’m 170lbs it should take about 15,470mg for a lethal dose, that’s equivalent to 1,190 ounces (~35 liters) of coffee or 148 8oz cups. Here’s the kicker, a normal resting kidney can only excrete 1 liter of water per hour, anything over that risks overdose. Baring all the other complications associated with drinking 148 cups of coffee, water will most certainly kill you first.

Variations in regional varieties, roasts and brewing methods can effect the amount of caffeine in each cup of coffee and cup of tea. Roasting coffee longer (darker roasts) causes more caffeine loss due to sublimation (changing from a solid to a gas). Tea is reversed, the more concentrated black teas are more caffeinated than the green and white. The caffeine molecule is a robust, bitter, white crystalline compound with a boiling point above 315 degree C (which is much higher than brewing and roasting methods) but sublimation can occur around 175 degree C.

However you enjoy to consume caffeine Cheers, and here’s a helpful chart for monitoring your intake.

Note: Some companies treat their coffee and/or tea with a chemical caffeine spray skewing the results.