Item — HN Reader

Observation: Coffee studies often report (in headlines and abstract and body) consumption in terms of cups.

At best, this refers to a standardized 250 ml or 8 oz measuring cup (unfortunately, still rarely what "a cup of coffee" generally means to those who read these headlines and adjust behaviour as a result).

At worst, the term is used to allow for ambiguity and variance expected in self-reporting.

I recognize there are many other variables that are even harder to measure than beverage volume, like mg of caffeine or diterpenes or antioxidants. But "cups" just seems so loose.

Related question: Is there a somewhat accurate amateur method of measuring caffeine content? I vary my beans and roasts and method a fair bit for fun and taste. e.g. various beans, light vs medium vs dark roasts, varying apparatus, mass of beans per "cup", filter types, and brewing time. I would like to have insight into how much caffeine I'm consuming.

1 comments

Ahh, now here comes the fun part. There is no standard.

250ml is 8.5 ounces. Some places in Europe standardized on this.

A cup of anything else is 8 ounces.

A "cup of coffee" (the actual unit) is 6 ounces, and this is the standard everywhere where 250ml isn't, and we're not in Japan; but even though the US follows the 6 ounce standard, the USDA considers a cup 8 ounces on their nutrition table.

Japan has standardized on 200ml (or about 6.7 oz).

What SHOULD be measured is not liquid volume, but bean weight (measured in grams; even Ameicans measure it in grams when they're the type to weigh it instead of just throwing ambiguously heaped tablespoons in); and then shifted according to that blend's particular caffeine content (outside of specialty products with high-caffeine bean variants, caffeine content can vary about +/- 50% depending on the origin of the beans (roasting does not effect caffeine content meaningfully, although the myth lives on)).