It is simple math to figure out how much alcohol a glass of wine contains, with a few variations.
First of all, the question is: how much wine are we talking about?
A good serving of wine is 125 ml, meaning you should be able to get 6 glasses of wine out of a 750 ml bottle. I must confess I usually get a good five servings per bottle!
By the way, in Austria, when ordering wine, you would order an "Achtel" or a "Viertel", an eight or a quarter, which are respectively 125 ml and 250 ml, the latter one effectively being a double, always served with half in the glass and the other half in a carafe to the side.
As Germans tend to be a little more precise than others, they measure their servings and customers can verify that they were not shortchanged because in restaurants and bars glasses are required to have a fill line indicating the specified volume.
Assuming the 125 ml and a 12% of alcohol by volume, this would be 15 ml of alcohol.
Does a glass of whiskey contain more alcohol than a glass of wine?
A Scotsman may order a dram of whiskey (of course, not generic whiskey, but his particular preference) in a pub. He then gets 25 or 35 ml of whiskey. Let's hope for the best: 35 ml.
By the way, in the USA you might get a drink the size of a jigger, which is 44 ml.
So 35 ml with a 40% alcohol by volume makes for 14 ml of alcohol.
Now what are the effects of 15 ml of alcohol?
The effect of alcohol on the human body
First of all, opinions are in harmony about one thing: too much alcohol is a bad thing for your body in so many ways. Healthline gives you 23 reasons to moderate or stop your drinking: 23 Effects of Alcohol on Your Body (healthline.com).
OK, you are still reading. Let's do some math, but first define BAC: blood alcohol content.
Cutting a few corners, you could say that an adult may have about 5 liters of blood (male, average height, average size). Now assume you drink the whole drink at once, that the alcohol from your drink is immediately transferred to your blood and the alcohol is divided evenly throughout your blood. That would lead to a BAC of 15 ml divided by 5 l (5,000 ml) is 0.003 or 0.3%.
According to different sources, the liver can metabolize about one standard drink with 15 mg of alcohol per hour (I will pretend here that 1 ml of alcohol weighs 1 mg, which is not quite true). The good news is that some 10% of the alcohol intake disappears via breath, sweat and urine, but we will not take this into account.
Now, all this means that if you drink at a frequency higher than 1 drink per hour, your BAC will increase to higher levels. And at some point, it is going to affect your immediate functioning.
Dutch traffic laws state you are not allowed to drive with a BAC above 0.5 grams per liter. Which in itself is a strange unit, weight per volume. 0.5 grams per liter more or less equals 0.05% or, as it is commonly referred to, 0.5 promille (per thousand).
Apparently, British hold their drink better than others; the UK (with the exception of Scotland) has a 0.08% limit.
So the law assumes we are not in control at a BAC of 0.05%.
How much do you need to drink to accomplish a level of 0.05%?
Assuming one drink per hour (total of 3 drinks in 3 hours), we can calculate this (with all the assumptions mentioned):
A drink every 45 minutes (4 drinks in 3 hours) would lead to:
And a drink every 30 minutes ( drinks in 3 hours):
In this last case, it would take another three hours to get your BAC back to (almost) 0 g/l.