You know, I have often wondered about the odd measurement of alcohol strength that the UK uses - aka "the unit" - because it is so obscure. For me, I would like to see the number of ml of pure alcohol listed on every bottle. Wouldn't that be the easiest thing to do? Instead, we in Canada get percentage meaning we have to do simple math. Such a task can leave a simple soul like me lost.
But the British take it one step of abstraction further with this "unit" stuff. I have in front of me a 500 ml bottle of the overly-named "Duchy Originals from Waitrose Organic Old Ruby Ale 1905" and see two diagrams. One has a glass with "1.4 UK units" in the drawing of the glass and 284 ml below it. The other has "2.5 UK units" super imposed on a silhouette of a bottle. I don't know what the 284 ml exactly means but I presume it is a half pint. So, it suggests that I need to consume 500 ml bottles of beer in 284 ml portions. Silly advice #1. These measures each seem to be two "units" of procurement and consumption. But neither are a whole "unit" in the sense of the health warning, if only because each diagram displays a number with a decimal. So what is this sort of "unit"?
Pete Brown to the rescue. He sent me a set of the new paperback editions of his three books on beer. I plan to give the autographed set as a gift in the 2010 Christmas photo contest but, as Man Walks Into A Pub is now in its second edition with new material added (and a far less ugly cover) since I reviewed it back in 2003 - actually before this blog separated off of the mothership - MWIAP will be presented with a dog-eared gift. First passage I read? It's about "units" at page 392:
The invention of safe limits for alcohol unit consumption was one such "unverified fact". A unit is ten millimetres of ethyl alcohol, the amount the average healthy adult can break down in an hour. In 1987 the Health Education Authority and Alcohol Concern agreed that units were a good way of teaching people about alcohol consumption, and recommended that men should drink no more than twenty-one units a week, and women no more than fourteen. Above that level, they claimed, the risk of alcohol-related harm increased exponentially. What they didn't see fit to mention was that only five years earlier, the Royal College of Physicians and the British Medical Journal had been advising that the safe limit for men was fifty-one units a week.. There was no new research to back up the reduction to twenty-one units five years later, and not reason for doing so.
What I find extraordinary about this passage is not the shift in official advice during the 1980s but the confirmation that a unit is "the amount the average healthy adult can break down in an hour." Because it gets me wondering what that means in terms of comparison to drunk driving standards. Here in Canada was happily have a dual law. 
You can be, generally speaking, convicted for driving while intoxicated or convicted for blowing into a breathalyzer and being found to have over 0.08 mg (I think "mg") of alcohol per "X" litres of blood. So, on the one hand, you can be intoxicated and be under the scientific test if you have low tolerance. You can also be not intoxicated but have too much booze in you to drive if you have high tolerance. As a public standard for safe driving, it works as far as I am concerned. I am, after all, a Beer Blogger Against Drunk Driving.
The thing is, I am not sure that you come anywhere near those limits by sticking to "the amount the average healthy adult can break down in an hour" and I thought for some reason you would have to. Let's review. The bottle of "1905" says as part of the UK warning that it is recommended that I have no more than 4 "units" - or one litre of 5% beer - a day. Two bottles of "1905". According to this blood alcohol calculator, that would give a 200 lb man an level of 0.047 after one hour since the first drink. Me, I am bigger so the level is lower. Please check my math. Have I got this right?
Now, I am quite a happy taxi hirer and have absolutely no issue with grabbing a cab at any occasion. I would have to sit a bit longer for two pints of 5% to be comfortable driving and, still, probably would not. Personal decision. But I would in no way think that I have done myself a long term physical injury by having a third pint over a span of two hours. Yet that is what the UK standard of "units" suggests. I think I might feel dragged out if I did that every day Monday to Friday. I might even start to tweet too much as we all are witnessing from the Great American Beer Festival right now. But even if I did have three pints for five days in a row, I am still well under the pre-1987 recommended level for weekly intake and would feel my best again after a couple of days on black tea and cucumber sandwiches. Check my math. Is that correct?
What does this tell us? First, that the medical advice for, what shall we call it, "drinking and living" presents a significantly stricter standard than the criminal one for "drinking and driving." Second, it tells me that I want to know much more about the difference between 20 and 51 units a week. What exactly does it mean? Is the liver so fragile that it cannot take a pace of alcohol consumption that is greater than "the amount the average healthy adult can break down in an hour"? How is it that the body is born with a capacity to break down a naturally occurring substance like ethyl alcohol and yet it is prone to being damaged by it at a level of consumption far lower than the level that causes the minimum level of motor control disfunction requiring legal intervention for the safety of others?
Third, it tells me that you need to get the second edition of Pete's first book even if you bought the first one seven years ago. It's full of handy stuff that gets your unaddled brain going.
Comments
Barm - September 18, 2010 2:46 PM
The unit isn't obscure at all. It's 10mL of pure alcohol. It's just that the government thinks we are too stupid to deal with this simple bit of information and refuses to explain it in its publications, preferring to use vague phrases like "half a pint of standard-strength beer" instead.
Alan - September 18, 2010 3:13 PM
It does remain obscure because it is not stated to be 10mL of pure alcohol on the label. It is also obscure in that there is no explanation - let alone supporting evidence - that 10mL of pure alcohol is at all significant.
Jon K - September 19, 2010 1:18 PM
The "unit" isn't used in the UK as a measurement of alcohol strength. We use alcohol percentage by volume (alc % vol). The "unit" is, as Barm points out, equivalent to a quantity of alcohol. I suppose the idea is that this helps people to keep an eye on their intake without having to do a load of maths. So it's an option for the producer to label units per "serving" and per container, or both. Or neither.
Me, I stop when I'm drunk, and don't start again until I've shifted the hangover.
Alan - September 19, 2010 1:28 PM
I am touched by your concern as to my personal grasp of the concept but it was more in the nature of a literary device - but I was not aware that this labeling is optional. Which is interesting. If it is optional is there anything to read into which brewers do and do not include it in their packaging?
Jon K - September 19, 2010 2:20 PM
Use of "unit" implies that the producer is probably paying attention to the Portman Group guidelines (pdf), or to the British Retail Consortium, or something.
Alan - September 19, 2010 8:34 PM
Ah, so they are complicit.
Gary Gillman - September 20, 2010 7:59 AM
As applicable to Canada and I would say the U.S., the concept of the alcohol unit derives I believe from the practice, still current but changing in certain areas, of selling beer in 12 oz. containers at 5% ABV (Gay Lussac system), the standard for many years in Canada and still applicable to a large degree. As all beer fans know, the U.S. calculated the alcohol content by weight and its 4% when translated to GL came out to about 4.8% ABV, an odd-seeming level you sometimes see in Canada too now. I still think in Imperial measures, and the old unit system here was derived from that, so I'll stick with that. So, .6 of an ounce of that amount was pure alcohol. 5 ounces of wine was ditto (5 X 12% ABV) and 1.5 oz. spirits at 40% ABV the same. Two of any such drinks was two units. Many people informally used that as the basis to determine consumption ("two is my limit" or whatever). Of course, that approach does not reveal any medical system or value. At one time, I believe two units did not put you over the limit for the Criminal Code's breathaliser limit, but I think that has changed in recent years. Three units in the sense indicated seems to equate to four in the U.K., but I did not check the numbers on this. I believe though I've seen similar medical advice given here, i.e., 3 drinks per day or 21 per week should not be exceeded. Just based on the effects that amount of drink has on one's overall sobriety, I would say that is reasonable advice (if perhaps too generous), but that is just my opinion. As for whether it reflects good medical advice, i.e. in terms of whether the human organism can physically take that safely over time, I just don't know. Everyone must decide for themself but it is good to have this guides I think because many people don't think of it, a drink to them might be a pint of 6% ale or two ounces of U.S. proof bourbon (50% ABV, thus one ounce per alcohol), and a limit must be drawn somewhere.
Gary
Gary Gillman - September 20, 2010 8:09 AM
It's early in the morning (after a Sunday which did not exceed the 3 unit per day level!)) and I need my coffee. I meant in my last remarks to state that a unit system such as Britain has is a useful guide, and of course 2 oz. of 50% ABV bourbon would come out to 1 oz. pure alcohol.
I should add that accordingly, when I count drinks, I always convert to the unit system I mentioned. And so 20 oz. of 5% ABV beer is just short of two standard drinks. 12 oz. of beer at 10% ABV is two drinks, and so forth.
Gary
Alan - September 20, 2010 8:56 AM
All that math - and you follow my same shorthand for converting to a 12 oz 5% beer! But is the question really not this one:
"...whether the human organism can physically take that safely over time, I just don't know."
but this one
"...whether the human organism is bothered over time, I just don't know."
See, I get the beer makes you fat thing but that is a net result. Too many calories and not enough exercise. But what the "units" and other forms of analysis promotes is thinking in gross. I am a very large person - and not only in terms of overweight. How does the "male" "female" division apply when me at very big drinks next to my pal who is a foot shorter and half my size? Do the 4 units a day really apply to the tiny? Or are the tiny being sacrificed to the median?
Gary Gillman - September 20, 2010 9:14 AM
Safely, bothered, I'd read these as similar or at any rate I didn't mean anything really different to bothered.
Point well taken re the issues of average application. These systems are guides and we all have to adapt them to our weight, our other habits and frankly our proclivities (some are more risk tolerant, some less..). But overall I think these systems have values. Looking now too at that PDF, I think the British system is less generous than ours, i.e., our 3 units per day would be their 4.8. But anyway, I use the Canadian system as a rough guide, I find it helpful.
Gary