I'm a newbie with a question on carbonation. My first brew, an American IPA, sat in the bottle for about two weeks before refrigerating and I had great carbonation and an overall good beer. My second batch, a Fat Tire clone, was bottled for a week and I decided to crack open a bottle to test it following a day in the frig (just for this one bottle). Almost NO carbonation, very flat. Am I in trouble with this brew or simply impatient?