The “Scientific” Ratio of Coffee to Water

in Brewing Coffee

Email from Peter Rudolph:”In your frequently asked questions, I believe there is an error. You stated, “32 tablespoons per pound.” I believe you are confusing fluid oz. and weight oz. There are 2 tablespoons per 1 fluid oz. However, there is 16 oz weight in 1 pound. The only way to assert 32 tablespoons (volume) equals 1 pound (weight) is to assume that 1 fluid oz. equals 1 oz. weight. 32T(1fl-oz/2T)(1oz/1fl-oz)(1lb/16oz)= 1 pound. However, it is unlikely 1 fluid oz equals 1 oz weight.” – Peter Rudolph


I appreciate the e-mail.  I remember at the time looking for some “scientific” way that I could calculate the perfect ratio of water:coffee and you definitely caught the flaw in my thinking.

The “perfect” amount of coffee to water gets tossed around a lot, so I’ll tell you what I do in my kitchen as a rule of thumb.  You will either load a certain amount of whole beans into your grinder, or your coffee is already ground and you’re loading a certain amount of it into your coffee maker.

There is more pre-ground coffee in a scoop than whole beans because of the air in between beans taking up space in the scoop.  I have what I believe is the “standard coffee scoop” that I see with any coffee container.  My understanding is that it corresponds to a tablespoon but it seems to me to be bigger than a tablespoon.  My method…

I put one even coffee scoop of ground coffee per cup of coffee I’m making, or one generous scoop of whole beans per cup of coffee I’m making.  I’m not using “cup” as in metric cup, but rather as a “standard mug” of coffee, or what corresponds to a small-size cup of coffee at most retail coffee places.  Many coffee maker carafes today show you a number of cups, but these are metric cups, so that a 10-cup coffee maker actually makes five cups of coffee per pot – one metric cup of coffee in my opinion fills up only half of a standard mug of coffee.

I hope that makes sense and clarifies.  Thank you for your e-mail.


  1. does a scoop of ground coffee = 1 tablespoon?

    Comment by buzzie — February 4, 2011 @ 4:18 pm

  2. Yes, buzzie, I would suggest a heaping tablespoon of whole beans. The coffee scoop is better than a standard kitchen tablespoon as it is deeper and will hold more of a generous portion.

    Comment by Marc Wortman — February 5, 2011 @ 12:15 pm

  3. starbucks suggest 2Tbsp (10 g) of ground coffee for every 6 fl oz (180 ml) water.

    its printed on the bags of their ground coffee.

    Comment by michael — February 22, 2011 @ 7:30 pm

  4. Thanks, Michael. My sugestion is to experiment and find the coffee strength you like, starting on the generous side with coffee and adjusting to taste. The 2Tbsp suggestion from SB is good, with 6 fl oz being the typical amount of water in a “mug” of coffee.

    Comment by Marc Wortman — February 25, 2011 @ 1:38 pm

  5. Sorry for the lateness of the reply but I really appreciated the info. I also checked the blog by the way.

    Comment by Alex — May 8, 2011 @ 11:55 am

  6. No problem Alex, I hope it helped.

    Comment by Marc Wortman — May 10, 2011 @ 8:46 pm

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