Are we sure? The standard USA measure for a cup of coffee is a 6 ounces. (Evidence: search Google on how much grounds you use per cup of coffee.)
Speaking of, how much grounds are used per cup in the research, and what kinds of grounds are used?
This has perplexed me for years, and the looseness in the three factors makes a big difference in how much caffeine or other “coffee stuff” one consumes.
When researchers say X cups of coffee, they’re entirely relying on their respondents’ personal reporting. So the answer is your best bet is to assume a cup of coffee is about what the average person would call a cup.
Yes, you are not controlling for the amount of coffee consumed. But that should cancel out in a population based study. The null hypothesis should be that humans drink coffee in a gaussian distributed way (not like with alcohol where the consumption is exponentially distributed). If you then randomly sample from that coffee drinker population (again, gaussian distributed), you can then control for variations in the coffee consumption by comparing the averages of coffee drinkers to non-drinkers.
But, yes, this does center around the hypothesis that coffee consumption is normally distributed. To confirm that I'd assume that there has been some research done on coffee consumption. Research that I have not done, to be clear. But I with no priors, I'd assume a normal distribution, because, well, darn near everything in bio is normally distributed.
I've had espressos in Colombia and Portugal that probably had more caffeine than in a mug of what Americans drink.
So volume doesn't really say much.
Do we? How do Brazilians prepare a cup of coffee? Is the process different or do you just use a lot more grounds per amount of water?
> Do we?
An 'Americano' is literally watered down coffee.
Yes, I know, espresso is a kind of coffee, but it’s not what Americans are referring to as when they say “coffee”.
Do Brazilians drink what I call espresso and call it coffee?
I didn't mean my observation as some sort of criticism. It is just an observation. Every person should just drink it how they like it.
I don't know if these things are really 'standardised' at all. Who'd have responsibility to do that?