Brewing -- the European Standard:
This Brewing Control Chart reflects the European standard and taste in brewed coffee. The important thing to note about this chart from the Special Coffee Association of Europe is that the same extraction is preferred even though the SCAE strength standard is higher. The American region of optimum balance is shown as an orange rectangle.
Of course, the SCAE standard is in metric units. The diagonal brew ratio line approximately though the center of the optimum balance region is 60 grams/liter, equal closely to 4.0 ounces/1/2 gallon.