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Comment by OJFord | Hacker News Reader

And surely the amount of water is inconsequential, why can't we just use grams of actual coffee? Then we don't have to worry about how many espressos are in a 10oz mug. (Nevermind what that person's considering a standard dose for the espresso!)

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Measuring extraction ratio on coffee is difficult and wildly varies based on preparation method. The standard “cup” assumes 4oz of coffee, using 5oz of brew water (so, 1oz stays in the coffee grounds as waste). I believe there’s also a standard amount of coffee grounds used as well, though.

Different brew methods extract differing amounts from the coffee, so the amount of water is indeed consequential. Same grams of coffee in to a pour-over vs espresso would result in different amounts of extracted coffee material consumed.

True. I'm inclined to think it would be closer than 'do whatever you want in order to end up with an Xoz drink' though!

Prep method matters so much though. For comparison, a standard double shot of espresso is typically 18g of coffee. This would yield approximately 110mg of caffeine.

By comparison, the same 18g brewed using a pour over method should yield an 8oz cup of coffee with … likely around 170mg of caffeine.

Check out this James Hoffmann video specifically on this topic: https://youtube.com/watch?v=etnMr8oUSDo

I remember reading somewhere that the amount of caffeine in the cup is also proportional to the brewing time, therefore an espresso may not actually contain that much caffeine in the end (for the same initial amount of ground coffee, of course)

When I was in Organic Chemistry in College we demonstrated this experimentally. A cup of drip coffee had more caffeine than a shot of espresso. We were college kids so I'm not sure how consistent our how methodology was but the result was pretty consistent across all of us.

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