Im a new brewer and i decided to brew an american style pale ale. I used the extract recipe in "how to brew". It went through a vicious fermentation and after 2 weeks in the primary i bottled it and let them sit for a bit. When i opened my first bottle the flavor was just amazing...i was addicted to them. And now at the ass end of my batch i find the flavor going from full bodied to a glorified coors light. Any ideas of what could cause this? All i can think of is i may have introduced a small amount of oxygen to the beer when i siphoned it out of the fermenter. Any suggestions would be appreciated