title_body: Is diluting filter concentrate after the brew the same as brewing with the additional water?
upvoted_answer: No it is not the same. The brew ratio is important to extract the right amount of solubles from the coffee, ideally all the pleasant ones and only few of the unpleasant ones.
  If you brew with less water, you'll dissolve less of the coffee's goodness, and diluting that will lead to a thin coffee compared to a correctly brewed one.
  Conversely, if you brew with too much water, you'll extract bitter substances you won't like, so if you like a thinner coffe (like an americano) it's best to brew normally and then dilute.
  Unfortunately, the Aeropress is not really suitable to serve multiple guests.