Caffeine content

The caffeine content of a cup of coffee varies depending mainly on the brewing method, and also on the variety of seed.^[169]

According to an article in the Journal of the American Dietetic Association, coffee has the following caffeine content, depending on how it is prepared:^[170]

	Serving size	Caffeine content
Brewed	7 oz, 207 ml	80–135 mg
Drip	7 oz, 207 ml	115–175 mg
Espresso	1.5–2 oz, 45–60 ml	100 mg

While the percent of caffeine content in coffee seeds themselves diminishes with increased roast level, the opposite is true for coffee brewed from different grinds and brewing methods using the same proportion of coffee to water volume. The coffee sack (similar to the French press and other steeping methods) extracts more caffeine from dark roasted seeds; the percolator and espresso methods extract more caffeine from light roasted seeds.^[171]

	Light roast	Medium roast	Dark roast
Coffee sack – coarse grind	0.046	0.045	0.054
Percolator – coarse grind	0.068	0.065	0.060
Espresso – fine grind	0.069	0.062	0.061