It takes about one hour for the human body to break down one unit of alcohol; one unit equals 8mg or 10ml of pure alcohol. To get an idea of units, there are approximately:
- 2.1 units in a standard glass (175ml) of average-strength wine (12%)
- 3 units in a large glass (250ml) of average-strength wine (12%)
- 2 units in a pint of low-strength lager, beer or cider (3.6%)
- 3 units in a pint of higher-strength lager, beer or cider (5.2%)
- 1 unit in a single measure of spirits (25ml)
Basically, the body will take about three hours to break down the alcohol from a large (250ml) glass of wine, and about two hours to break it down from one pint of beer. However, with stronger lager or beer, it would take longer since that's equal to three units.
However (and very important) - the length of time it takes a unit of alcohol to break down can vary due to many factors besides the type & strength of the alcohol, including the person's weight, age, and metabolism; whether male or female; how much food has been eaten; and whether one is on medication and, if so, what kind.
Also, those with liver problems or have livers that aren't functioning normally will take longer to break alcohol down than others without liver problems.
The National Health Service in the United Kingdom recommends that males not drink more than 3-4 units of alcohol per day; females, not more than 2-3 units. This recommendation is basically the same as recommended by US health officials.