Alcohol metabolizes in the body at a real fast rate. In order to maintain a high or buzz from alcohol one has to keep the alcohol/blood ratio up at an intoxiced level. The buzz time on alcoholic drinks is about 1 hour to 1 hour and 1/2..depending on how much alcohol was consumed and the time taken to consum/body weight. However the upwanted after effects/hangover can last for hours.

You gotta drink alot to maintain a buzz is why I believe people drink so much.