The Beer Babe does the math – what craft ABV %s can mean for drinking and driving
I went to a defensive driving course a few months ago as a requirement for one of my jobs. I wasn’t surprised, but the video that they played was from about 1985 (complete with yellow suits with hideous shoulder pads – yikes!) and that I had seen it several times before in other trainings. As it should be, there was a section of the course on drinking and driving.
The slide that was shown at the training had the all-too-familiar “1beer=1wine=1shot” memory trick, so that you could count on your BAC (blood-alcohol content) going up by .02 BAC with each of those, and lasting for about an hour in your metabolism. And, that after several of the same kind of drink, you could still do a rough calculation in your head about what you’d consumed in one night, and make your determination about whether or not you are able to make decisions, or drive home safely. There’s a little math, but it isn’t too bad.
So, for example, we’ll take Joe, the college drinker.
If Joe has 3 “light” beers (the typical .02 BAC increase for each x 3 = .06 BAC) when he shows up and then plays a videogame for two hours (-.04 BAC), he’s only have about one beer left in his system and would be well under the legal limit to drive home (.02 BAC). However, if Joe drinks 5 beers in an hour (.02 x 5) and then drives home immediately, his BAC of .10 would be over the limit in all 50 states and dangerous.
Those scenarios are pretty straightforward. In the end, its all about time, and quantity. This is very simple, and for years was a useful “mental check” of whether or not driving home was advisable. But, this calculation is can be dangerously wrong if you’re drinking pretty much anything other than Coors/Bud (which come in at 4.2% ABV for Bud Light and Coors Light respectively). Most of my craft beer drinking friends don’t pause to consider how wrong this rule is.
For example, the average beer from Red Hook Brewery is 5.7% ABV, Sam Adams (not including Utopias) is 6.25%, and Stone Brewing is a whopping 6.9% ABV on average [1].
So if we do a few more calculations, this variation could begin to cause a huge problem:
If a beer is 5% ABV, each drink will raise the BAC about .024
If a beer is 6% ABV, each drink will raise the BAC about .028
If a beer is 7% ABV, each drink will raise the BAC about .033
What does that equate to?
If Joe suddenly turns into a craft beer lover, and drinks 3 craft beers in a night, then plays a video game for two hours (same as in the previous scenario) if he’s drinking a 7% ABV (that’s .033 x 3 = .099 BAC) he’ll start off with a .099 BAC, and after two hours be down to a blood alcohol content of .059– which is not a great number.
At .05% BAC or more, “impairment occurs consistently in eye movements, glare resistance, visual perception, reaction time, certain types of steering tasks, information processing and other aspects of psychomotor performance” [2].
If you do the math, a small variation in ABV can have a huge effect overall on sobriety – especially as far as beer is concerned. Additionally, extreme beers, Belgian beers and others can have ABVs in excess of 9%. Which, in our scenario with Joe, would give him a BAC of .088 after 3 9% ABV drinks and two hours – he’s surpassing the legal limit for drunk driving in 50 states.
So why bring this up? This holiday season there are lots of reasons to celebrate, and lots of great holiday beers to be had. But I thought it was important to share my revelation with you that I had in the back of an otherwise unremarkable driver’s education class. The 1beer=1shot=1wine rule should be stricken from the record, because it is no longer applicable to most beer available. Please be careful this holiday season when making drinking and driving decisions, especially all of you craft beer fans out there.
Happy Holidays!
14 Comments to “The Beer Babe does the math – what craft ABV %s can mean for drinking and driving”
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Thanks.
It’s true that you have to be careful with some of the craft brews. Some go down very quickly and you end up feeling oozy almost by surprise. We have an interesting link in my part of the world that is a little blood alcohol calculator. http://www.educalcool.qc.ca/en/evening-planner/ The only beer is 5% but you only have to do some simple math to get the number of single 5% 12 oz beers any other type of beer gives (count 5 beers in a 750 ml bottle of 10% beer for example). Good article.
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And even that general rule of thumb you put forth in regards to craft beers, is hard to use as the label might give you an overall average of 5, 6 or 7 percent, but the style can be where the issue really is. IPA’s tend to be a little higher.
While a lager or porter might run around 6 percent. IPA’s might run 7 to 8. A quick look in my fridge reveals the following:
Leinenkugel’s Nut Brown: 4.9
River Horse Hopalotamus DIPA: 8.5
Bear Republic Red Rocket Ale: 6.8
Flying Dog Raging Bitch Belgian IPA: 8.3
Sierra Nevada Torpedo: 7.2
Of course, by the same token – that 1 beer = 1 shot = 1 wine rule is also based on the idea that one shot is 80 proof. I have single malts that are as high as 113, and I won’t even get into the people thinking that a shot of 180 proof rum was the same as having a single beer.
Given that I have always wondered a bit about it, thanks for finally doing the math.
Excellent article! This is exactly why, when Mike and I attend a beer festival or beer dinner, we either arrange to stay at a hotel if it’s more than an hour away, or use public transit or taxis if it’s closer. When we visit Portland, for example, we’re staying in walking distance to the Maine Brewers Fest, and use the local buses or cabs to get to and from places like Gritty’s, Sebago, and The Great Lost Bear. It’s not really fair for one of us to have to not drink in order to be a designated driver. It’s definitely worth the extra money, as even one DUI can and does ruin many lives.
As for the holidaze…we’re staying at home. Winter brews are often much higher octane than others, so it’s just safer to buy them at the store and enjoy them at home. Also, at home, we are safe from those who do not drink responsibly!
Cheers!
This was a great article on a topic that all too often goes unmentioned in the beer blogging circles. I tend to think most craft beer drinkers are responsible drinkers – drinking not to get drunk but to enjoy the beer – but it’s always good to have a refreshing reminder.
ps – Dogfish Head’s beers on average are 9% abv!!!
I like the article. The math doesn’t seem accurate to me for some reason. I once saw an episode of Mythbusters where they were comparing talking on a cell phone vs drinking and driving (to see which was more dangerous, linky below). Both Adam and Kari only had like two beers and their BAC was .08. Scary stuff. Since I saw that episode I am VERY careful to have more than two beers before driving.
http://kwc.org/mythbusters/2005/06/mythbusters_killer_brace_posit.html
Another alternative is to buy an inexpensive breathalizer. I bought one once, but I went REALLY cheap and it didn’t work. Has anyone had any luck buying one that works and is semi-accurate?
-Lost
Carla,
Nice article. Curious though? I thought weight of the individual played a large part as well? Am I wrong?
Thank you so much for sharing this. You never know when you something you write might change the outcome of someone’s evening. I’ve said for a long time that after college my love of beer switched from quantity to quality. I am still re-learning how to drink (12 years later) and struggling with pacing myself correctly. Great story for all! Cheers, DA
Great article Carla! The quantitative geek in me loves the work you did.
I agree with John that crafties probably are a bit more responsible – both in terms of volume (my sessions are usually one to two tops because you can’t discern tastes too well after that) and location (I usually do the tastings at home or someone’s house as opposed to a bar).
A good rule is if you can’t figure out the math on if you should drive, don’t drive!
Also, if you’re out at a bar, tack on an extra factor of 1.33 as you’re served pints, not 12 oz bottles.
Great article Carla.
Just remember, 1 BrewDog Tactical Nuclear Penguin (32% ABV) 12oz is the equivalent of an entire 6 pack. Always check the ABV before partaking. You may have only had 1 drink but it can add up to more than you think. Nice article Carla – happy holidays!
yeah, i certainly have realized that six good Belgians certainly can creep on you during that ride home. That said, they usually only give you 8 oz or something smaller, making the 1 beer = 1 drink equation still applicable.