How Many Beers Can a Average Human Body Metabolise in a hour?
On average it takes about 1.5 hours for a body to breakdown and pass one unit of alcohol, in most modern lagers there are about 3 units of alcohol in a pint, thus one pint of lager will take around 4.5 hours to leave your system entirely - obviously these are AVERAGE - everyone will differ slightly, and some will differ greatly.
One and a quarter pints of lager can put the average man over the legal drink/drive limit for the UK.