Answer: A) 3 ounces. One serving is 3 ounces. But some restaurants pour triple that much into your glass. Over-indulging in alcohol not only adds empty calories, it creates danger for you and others if you get behind the wheel. The average person’s body can metabolize only 1 standard serving (10 grams) of alcohol an hour. That’s equal to 10 ounces of regular beer, 3-4 ounces of wine, or 1 ounce of hard liquor.