This is probably the third batch that this has happened to. Once brew is transfered into a keg via filter and force carbonated for a week the flavoure and bitterness is right. After about 2 weeks the beer goes extremely bitter and thick (viscosity) to the point where it becomes undrinkable. I thought it might be some sort of infection so i have pulled all of my kegs apart cleaned and put new seals in them and cleaned all of my beer lines still no luck. It only seems to be happening to my ale style beers. Dose anyone have any advice?