When using a drip coffee maker, there are basically two choices we make: the amount of water and the amount of coffee grounds.
If we use the same amount of coffee grounds but double the water, how much extra caffeine is in the resulting brew? Does all the available caffeine in the grounds get quickly liberated, so that there's not much of a difference between brewing with more water and diluting the brew with water afterwards? Or is it closer to the other extreme, where twice the water means twice the caffeine?
I saw on wikipedia that only about 20% of the caffeine is extracted for an 'optimal brew,' but I wasn't sure if that means we can extrapolate and say that the remaining 80% can be extracted just as easily.
I have the same question about the amount of coffee grounds. I only care to consider the 'normal brewing regime', that is with water at ~80-90C, 3-6 cups of water, and 1/4-1/2 a cup of grounds.