How Much Caffeine Is In A Cup Of Coffee?


how much caffeine is in a cup of coffee

If we were going to compile a list of the most frequently asked questions about coffee, Question #1 would probably be:

How much caffeine is in a cup of coffee?


Pop Quiz

How much caffeine is in a cup of coffee?

a)      2 to 12 mg per cup

b)      140 mg per cup

c)       330 mg per cup

d)      It depends

If you answered “A”—you are drinking decaf. Answer “B” is the average caffeine content for an average size cup of brewed coffee. Answer “C” is a 16 ounce cup of Starbucks’s Pike Place Brewed. Answer “D” reflects the uncertainty that comes with making these estimates.


The Estimates

As answers do vary, we compiled the following range of estimates:

{To keep a lid on our tendency to take coffee-related research to the master’s degree level, we limited ourselves to a maximum of five sources: two online references and three journal articles.}

Mayo Clinic: 95-200 mg  per 8 ounce cup of generic brewed coffee

UK Food Standards Agency: 140 mg per mug of filter coffee)

Bunker and McWilliams (1979): 107 to 151 mg per cup

Gilbert et al (1976): 29 to 176 mg per cup

McKusker et al. (2003): 72 to 130 mg per 8 ounces of brewed coffee


Why Is There A Range of Answers?

There is no one straightforward answer because of the number of factors, from bean to cup, that impact caffeine content.

The British Coffee Association lists the following factors that affect the caffeine content in a cup of coffee: the type of coffee bean, the roast, the grind, the amount of coffee used, the brewing process and the size of the cup.

To start with the intuitive parts first, the larger your cup, the more caffeine is in there. In terms of the grind and the amount of coffee used, research on the effect of grinding and brewing techniques on the caffeine content of coffee concluded that a finer grind and a higher coffee to water ratio both increase the amount of caffeine in the cup.

The counterintuitive part? The caffeine content is highest in light to medium roasts.


how much caffeine is in a cup of coffee

Caffeine Myths

We have a perception that coffee that “tastes strong” (like a dark roast) is higher in caffeine. Caffeine itself is odorless and tasteless. Intensified roasting does produce a different flavor profile, but it has an inverse effect on caffeine content.

An espresso drink will not (on average) contain more caffeine than a cup of brewed coffee. The espresso brewing technique translates to the water being in contact with the grounds for a much shorter period of time, which will extract less caffeine. The Mayo Clinic estimates that a one ounce serving of espresso will contain 40 to 75 mg of caffeine, on average. Empirical research on espresso drinks indicates a range of caffeine contents between 51 to 322 mg per drink. The ranges are similar to brewed coffee estimates, with the same six-fold spread in variability.

Another myth is that decaf is synonymous with no caffeine. The EU standard requires that decaffeinated coffee be 99.9% caffeine-free. This translates to a 0.10% residual caffeine level. There will be caffeine in a cup of decaf coffee, anywhere between 2 to 12 mg per cup on average.


How Much Is Too Much?

The Mayo Clinic defines “heavy daily caffeine use” as 500 to 600 mg per day, and cautions against exceeding this level.

Worried about your consumption? The Energy Fiend website has tables listing caffeine contents of beverages and other products, as well as a tool to calculate the toxicity level by beverage type and the consumer’s weight.

What is your favorite caffeine myth? Share it with us in the comments below!


Main Photo: Greg_Rodgers

Content Photo: tonx


Robyn is a freelance writer, editor and a serious foodie. A native of Seattle, she has found a new home in Northern California where she splits her time about equally between hiking in the redwoods and typing in local coffee shops. In addition to writing for CoffeeKrave, Robyn is currently working on a project to produce a short animated documentary—"Clipped and Tucked"—about her adventures in cooking recipes from antique cookbooks.

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