I have been wondering lately what exactly is the difference between drinking a higher alcohol beer and a lower alcohol one besides the obvious, that there is more alcohol involved. What I mean is ... what is the affect of having a couple of 6% beers versus a couple regular 5% beers.
Each beer has on its label the amount of alcohol by volume (APV). APV is the amount of alcohol contained in the amount of fluid in a bottle. For instance, a 12 oz (355ml) bottle of 5% beer, has 0.6 oz (17.75 ml) of alcohol in it which is 55% of the beer's volume. A 6% beer has 0.72 oz (21.3 ml) of alcohol in it.
OK, so now we know the alcohol increases steadily and not on a graduated scale.
But this does not explain the affect of drinking a higher alcohol beer versus a lower one? To do this, we must bring the amount of alcohol in a drink down to a common denominator.
I researched a few websites that bring about the idea of a "Standard Drink". They determine that a standard drink has 0.5 oz of alcohol in it. Interestingly enough this is the amount of alcohol in a 1.25 ounce shot of regular rum, whiskey or vodka, without mix. Now that we have a standard to measure against, we need a formula to determine how many standard drinks are in various alcohol levels of beer of the same size.
For the formula, we need to multiply the serving size by the amount of alcohol per volume to get the total number of ounces of alcohol in your beer. We then divide this by a standard drink of 0.5 oz of alcohol to see how many standard drinks a serving is.
That is the long version. The formula is a lot more simple. It is (number of ounces served) times APV x 2.
So for a 12 oz bottle of 4.2% alcohol it is 12 oz x .042 x 2 = 1.008 or close enough to call 1 standard drink for beer.
Let's see how the standard number of drinks grows as the alcohol content rises. We'll use the same 12 oz bottle (355 ml)
APV = Standard Drink
4.0% = .96
4.2% = 1
5.0% = 1.2
5.2% = 1.25
5.5% = 1.32
6.0% = 1.44
So if I am sitting at home and having three of Black Oak Brewery's delicious Nutcracker Porters (341ml or 11.5 oz @ 5.8%), it would have the same affect of my having 4 beers at 4.2%, or drinking 3.6 regular 5% beers.
I have some bottles of Grand River Russian Gun Imperial Stout in my fridge. Have to be careful with this one. It comes in a 500 ml bottle (16.9 oz) and weighs in at 8% APV so by the time I finish one bottle of this, it is like having almost 2.75 beers. Don't want to be pounding this one back! Even if they packaged it in a regular 12 oz (355ml) bottle, which they really should do for a potent beer like this, each 12oz bottle would still be like drinking almost 2 beers.
Really, this all makes great sense.
Here are some regular bottle and can sizes broken down from millilitres to ounces in case you wish to play with this formula.
341 ml = 11.5 oz
355 ml = 12.0 oz
473 ml = 16.0 oz (cans)
500 ml = 16.9 oz
The question here, though, is measuring the affect of drinking higher alcoholic beers. We can do this by measuring Blood Alcohol Level (BAL) using this pretty good calculator I found and the Standard Drink formula (a different chart is pictured to the right). You can use this calculator in different ways. What I am doing is feeding in standard drink sizes at 4.2% for a 12 oz bottle.
Lets take a 200 lb (91 KG) male. He has 4 - 4.2% APV 12 oz lagers over a two hour period. This comes to 4 standard drinks. His BAL comes in at .047%
Now, let's say this same person has the same number of 12 oz beers over the same period of time. He starts with a nice 4.2% lager, then has a nice 5% ale, followed by a 5.8% porter then finishes with an excellent 6% IPA. The number of standard drinks here is a little over 5, so really just one more. His BAL jumps to .066% which is 40% higher.
There is the affect! Just the equivalent of one more beer over a two hour period.
So the original question was what is the affect of having a couple of 6% beers vs a couple regular 5% beers? We'll do this over a 1 hour period. The 6% is equal to having 2.88 standard drinks and gives an approximate BAL of .04%. The 5% is like have 2.4 beers gives a BAL of .031%. This person has drank just under a half a standard drink more with the 6% yet the blood alcohol is 22.5% higher!
So as always, don't drink and drive and, if you are sitting at home having a couple of 6% ales and feel a buzz before you expected, that is why.