I work at a coffee shop that has a couple locations.  The one that I mainly work at is at a hospital.  There's a huuuuuuuuuuge difference in taste of coffee from the hospital location to the other store.  I found out that the hospital over filters the water and then goes through our filters to the machines. I've noticed that the coffee is more bitter and than our other shops.  Can over filtering change the flavor that much?  And how would you correct it?  I've already tried different grinds and different amounts of coffee with better results, but still not what I'm looking for. Any feed back would be greatly appreciated.  THANKS in advanced!!!