This is the question I get most often. The answer is it depends. At MoonBeans Coffee we weigh our coffee for consistency, but does that mean you have use the same process at home in order to achieve a great cup of coffee? I believe the brewing of coffee should be kept simple. Use high quality coffee with filtered water and measure an amount that produces the flavor profile you prefer. When using an inexpensive scale however you will get predictable results over and over again. Unless you are a coffee connisuer and in the business of coffee cupping for a living, 3 table spoons would be a good place to initially start. This will yield approximately 21-25 grams. I say approximate because this will depend on a couple of factors. The grind setting, course takes up more volume while fine will actually yield more coffee also producing a different outcome in flavor. The second, wether you use a heaping or rounded measurement. For some the difference of 3-4 grams will not make or break the cup while for others it will be the difference of a good morning or having mr. grumpy show up. The final decision is yours, to weigh or wing it.
These coffee measurements are base on a 12oz (340g) of water.