Caffeine content of coffee is not a standard unit. Variables include:
• instant generally contains less caffeine than fresh
• type of coffee bean
• grinding
• how the coffee was made e.g. filter verses percolated
• where it was made
Where it was made? In 2005, a university study measured the caffeine content of 97 short blacks from restaurants on the Gold Coast, Queensland, Australia. The strongest sample contained nearly nine times as much caffeine as the weakest.
Ben Desbrow et al: "An examination of consumer exposure to caffeine from retail coffee outlets": http://www.academia.edu/1879395/An_examination_of_consumer_exposure_to_caffeine_from_retail_coffee_outlets / caffeine coffee variability consumer exposure objective analyse distribution caffeine doses obtainable espresso coffee sold sample commercial coffee vendors Gold Coast Qld Australia design espresso short black coffee samples purchased analysed caffeine content micellar electrokinetic capillary chromatography MEKC coffees systematic cluster sampling five major retail centres centers results ninety-seven espresso samples analysed considerable variation caffeine content range per serve concentration range contained 120 mg caffeine samples exceeded 167 mg per serve conclusions implications heavily caffeinated samples findings frequently cited caffeine values similar data recently collected accuracy previous intake modelling regarding caffeine use Australian population probability consumer exposure high caffeine doses greater sample numbers variability variance within retail ground coffees caffe latte caffè caffé lattè latté mocha cappuccino ground coffee beans brewing dripfilter French press cafetière percolator /
