The experts say as long as possible. It can take the liver about an hour to metabolise one ounce of liquor or one standard drink, according to The University of California, Santa Cruz’s health centre , so at least that long if you’ve just had one glass. However, there are other factors that can impact the way you process alcohol and how intoxicated you are, such as gender or medications you’re on, according to guidance from Bowling Green State University. So it’s best to wait longer. Hokemeyer recommends at least four hours per drink to be safe.