Our coffee maker instructions often refer to a "cup" of coffee. These cups are whats marked on the side of the coffee maker showing how much water is in the reservoir. The instructions never define what a "cup" actually equates to. It appears to about 6 oz. An old coffee maker seems to also have had this definition of "cup". The coffee beans we got from the local coffee shop also have instructions indicating one scoop of beans per 6 oz cup.
To be clear — Is a "cup" to a coffee maker always 6oz? and therefore it has nothing to do with the Imperial unit "cup" which is 8oz? Its more a notion of a typical serving size of coffee?
Best Answer
Assuming you're talking about USA usage, you're correct, a "cup" is usually 6oz. In the USA, the standard size for a "cup" of coffee is 6oz, even though nobody drinks cups of coffee that small (12oz to 20oz is more common). For that matter, the size of a "cup" of tea can be 5oz or 6oz when the number of "cups" a teapot holds is listed; a "6 cup" teapot is only 32oz.
However, be careful how the word is used in American recipes. If a recipe calls for a "cup" of coffee, they are more likely to be calling for an 8oz cup, rather than a 6oz cup.
I can't find a clear reference as to where the unrealistic 6oz measurement for a cup of coffee started. Possibly the result of Mr. Coffee, but we're stuck with it as customary now.
However, even though a 6oz cup of coffee may be customary, specific coffee maker manufacturers may use different measurements on different models, including cups as small as 4.2oz. So don't assume unless you've checked.
Oh, and also note that the 8oz cup is American, rather than Imperial measurement. An Imperial cup is around 10oz, although you're unlikely to encounter this measurement in any recipe published after World War I.
Confused yet?