About one drink/hour
The liver actually gets "revved up" the more you drink, and heavier drinkers can metabolize more alcohol
, but the alcohol ultimately causes damage.
Once that damage is severe, the liver can actually metabolize less alcohol. One drink per hour is about the rate we metabolize, if by one drink we mean a shot (1.5 oz) of 40 percent spirits, 12 oz 6% beer or 5 oz 10% wine.