Background Notes on Measures - 6
The Alcohol Content of Drinks
Subject Headings are:
What's it all About?
What Standards?
Country Standards
How Much Alcohol? (AbV)
What Size Drink?
Sensible Drinking
Binge Drinking
Blood Alcohol Concentration (BAC)
Drinking & Driving
What is Proof?
Alcohol and Calories
A Personal Audit
Note that in all of this work, all figures have been rounded to *reasonable* degree of accuracy.
Ethanol or Ethyl alcohol. C2H5OH
Boiling Point 78.3C     Relative Density 0.789 @ 20C
A colourless flammable liquid, having a mild odour and a burning taste. Generally known as alcohol, it is the active constituent of alcoholic drinks.
It is also used as a fuel and a solvent.
Caution The main purpose of this work is to enable those interested to "get their sums right".
These 'Background Notes' are only that. The facts and figures given here have been collected
from many sources and NO guarantee as to their accuracy is given or implied.

What's it all About?
There is now a considerable body of opinion supporting the view that alcohol, in 'reasonable' amounts, can be of benefit to the health and general well-being of the human body. And there is unaminous support for the idea that an 'excess' of alcohol is harmful. But the big question is, what is 'reasonable'? Which prompts the question how much alcohol do people consume anyway? Which, in its turn, makes one ponder on how can you measure it? Particularly, how can you measure it in such a way that results are comparable? Whilst it was easy for medical/scientific people to refer to millilitres or grams of alcohol, these were not the sort of units to be using when trying to convey messages about alcohol consumption and its effects on health, to the general public. It was thoughts like these in the late 1970's and early 80's which led to the idea of creating a *unit of alcohol* or a *standard drink*. Various names are used but all are referring to a unit which contains a specific amount of alcohol.
What Standards?
So, how much should that specific amount be?
With no overall world-wide guidance, each country was free to set its own standards and so, in 2002, it is possible to identify 16 different countries which have (between them) set 10 different values ranging from 10 to 25 millilitres of alcohol as the size of their basic unit.
Clearly it does not matter what the *standard* is set at, within any particular country, but it does seem a pity that they could not have agreed on an international standard.
As a further help(?), some set their standard in grams, others in millilitres. At least they all appear to be talking about the same alcohol (of known density) which makes it easy to change from one to the other..
Country Standards
Here is a table showing the sizes of a *standard* unit of alcohol in various countries.
The values are given in both grams and millilitres [mL]
Sizes of Standard Units
CountrygramsmL       CountrygramsmL
Finland1113.9New Zealand1012.7
How Much Alcohol? (AbV)
The above information would be enough if we drank our alcohol neat! It would be so easy then to know exactly what our intake was.
But we drink our alcohol mixed with water. It may be coloured and flavoured water but, for our purposes here it is still water. And what we now need to know is, just how much alcohol is there in the water?
The simplest way of measuring this is by saying there is a particular quantity of alcohol in a particular quantity of water. The quantities could be given by weight or by volume. It is usual to use the same units for both and the most often used is volume. One further refinement is to dispense with naming the units at all and express it as a percentage. This is known as the %AbV (or AbV) meaning percentage of alcohol by volume.
The value of the %AbV can vary from 0 (what alcohol?) to 100 in theory. In practice, anything above 90 makes for a rather unstable drink since it has a very high rate of evaporation.
Unfortunately, the alcohol content is still given by its "proof" value in many places. For an explanation of this, see What is Proof? below.
The following values are a very rough guide as to what may be expected:
beers 2-7   %AbV
wines 10-15
sherries & ports 20
spirits & liquers 20-40
but much higher values do exist, and are marketed.
Tequila and absinthe can be over 70 %AbV for instance.

In the metric system, it is very convenient to know that the %AbV multiplied by 10 immediately tells us how many millilitres of alcohol there are in 1 litre of the mixture. But other measures are much used and the arithmetic is not so easy. A separate calculator (AbV and Equivalent Values) is available to deal with this.
Go to the top OR the AbV and Equivalent Values Calculator
What Size Drink?
Unfortunately, we do not order our drinks in millilitres [mL] and that makes it difficult to make direct use of the above information.
When asking for a drink we indicate the size in a wide variety of ways. A list would include words like: bottle, can, fifth, gill, glass, jigger, middy, nip, ounce, pint, pony, pot, schooner, shot, stein, stoup, stubby, tinny, and many more. Note that very few of those are specific measures. There may a general acceptance (nationally or locally) of what is meant, but they are not covered by legislation. And even where they are you must remember which standard is being used. For instance, a pint(UK) is not the same size as a pint(US).
To help in this, the idea of a *standard drink* has been established in the countries listed above. It is based on the *standard unit of alcohol* used in that country and is generally explained in words such as, "A standard drink is one pint of beer, or one glass of wine." And you can't make it much simpler than that!
Even allowing for the fact that such explanations are only intended to be used within the country in which they are issued, the shortcomings of such simplicity must very apparent. (Like how big is that glass and how strong is the beer?) But, bearing in mind that its principal purpose is to help people become AWARE, then it is a good starting-point and, very often, there is more detail available in the small-print of the footnotes.
There are two calculators which are intended to give precise values of the number of *standard drinks* or *units of alcohol* in any given quantity of liquid, provided that the %AbV is known. One deals with all the above listed countries, and the other is specific to the UK. They can be called from here.
Units of Alcohol Worldwide
Units of Alcohol in the UK

When dealing with lots of data (statistics) there is a compulsion to reduce all those numbers to a much smaller collection that the mind can more easily grasp and even, whenever possible, to a single figure. The best known example of that is the average.
But it should never be forgotten that it is only ever a rough approximation trying to represent a whole conglomeration of values. And it is essential to remember that, particularly in this work, where statements are made about people, who are very variable creatures indeed. The word average has its own health warning attached.
For instance, the statement may be made that "the body of the average person can deal with 6 grams of alcohol per hour". But that has to be seen only as a guide to the size of the amount one would be looking for. It actually depends upon the internal make-up of the person, as well as their weight, health, sex, and several other factors. Some can deal with a lot more than others.

Sensible Drinking

The principal reason for knowing about *units of alcohol* and *standard drinks* is so that advice may be given on drinking without damaging the body.
The part of the body which is most at risk from alcohol is the liver. On this organ falls the major work of disposing of nearly all the alcohol consumed. If the liver is overworked it will fail, and the consequence of that is death.
Think of the liver as a filter and, just like any filter, the rate at which liquid (alcohol in this case) can flow through it is determined by its size and condition. On average, the liver of a *full-sized normal healthy adult* can process 8 to 10 mL (about 1 UK unit) of alcohol per hour.
BUT, don't think that it can keep that up for 24 hours a day, 7 days a week. There are certain other effects which are cumulative, and bad!
Advice on sensible drinking is usually given in the form of the maximum number of *units of alcohol* or *standard drinks* which should be consumed in a day with another maximum for the week. Somewhat surprisingly, considering the variation in sizes of the respective units, it does not vary widely over the different countries. Very broadly it is
Men 3-4 *units* per day with a weekly maximum of 28
Women 2-3 *units* per day with a weekly maximum of 21
Lots of other advice is available. Like, have at least one 'alcohol-free' day a week, use lower limits with age, never have more than 6 units in any one session, and so on. Best of all, "Less is Better!"
Perhaps most important is the fact that women appear to be much more at risk than men. That is, for the same quantity of alcohol, on average women's health will suffer more than men's.
Heavy Drinking
A recent (July 2003) paper on the relationship between drinking and earnings defined heavy drinking as being more than 50 units (men) or 35 units (women) per week.
The overall conclusion was that (on average!) drinkers earned more than teetotallers. But, for those who regularly exceeded the usual guide figures, 28(m) or 21(w) per week, and especially those who became regular heavy drinkers, the earnings dropped off.
Could be summed up as: "Being sociable pays off, being a drunk doesn't!"

Binge Drinking
What is 'binge drinking'?
There is no *official* definition. Most people have some idea what the term implies. Like "Drinking too much, too fast!" But trying to turn that into a clinical definition is just about impossible. How much is "too much" and how fast (how long it took) is "too fast".
Looking at extremes, we would surely not consider someone drinking enough to become mildly intoxicated after 4 hours as having been on a binge, but someone who became paralytic (regardless of the time it took) certainly had!
A reasonable starting definition is "a binge involves the consumption of 8 units (for men, 6 for women) or more, of alcohol in a single drinking session." But it comes with all sorts of queries and caveats. How long is a session? What is the condition of the person being assessed? Are they used to it? Are they large or small? Are they in good medical shape? What is their mental state? Was food being consumed at the same time? And so on.
No matter what the definition is, binge drinking is certainly bad for one's health. In the short term it could mean death from alcohol poisoning (or by choking on their own vomit whilst unconscious), and in the long term, a general deterioration of health at a faster rate than it might otherwise.
Avoid it!

Blood Alcohol Concentration (BAC)

After all that we can get around to actually drinking the stuff, so that the alcohol is, at long last, inside your body. What happens next?
Well most of it is absorbed by the blood stream and is carried around the body, performing its work as it goes. As a part of that process, and important to our survival, it is also being taken out of the blood by the liver.
The fact that it is in the blood stream, and that the amount can be measured, enables it to be used to express the degree of intoxication. This measure is known as the Blood Alcohol Content [BAC]. It is usually given as milligrams of alcohol per 100 millilitres of blood, written as
mg/100 mL or, in SI terms, mg dL-1
(dL = decilitre = 100 mL)
The take-up of alcohol by the blood is quite fast. Typically, any alcohol taken into the body appears in the blood within 30 minutes. An important figure is the rate at which it converts into BAC. Very roughly, 10 grams (12.5 mL) of alcohol increases the BAC of an average person by 20 mg/100 mL
Note that the increase in the BAC depends only upon the amount of alcohol taken in, and time does not come into it. Its elimination is another matter. No matter how much is present in the blood, the liver can only process it at a given rate. On average the BAC will drop by 15 mg/100 mL in every hour.
The consequence of that is, even several hours after the last drink the BAC can still be at a level which may be unacceptable.
Remember these figures are only a guide, and will vary with individuals.
Drinking and Driving
It is the BAC which determines whether a driver is legally allowed to drive or not. Some countries allow only 0 (zero) BAC.
A BAC of 10 mg/100 mL is found in some places, also 20 (for certain categories) but a BAC of 50 mg/100 mL seems to be the limit most often used.
The UK has one of the highest limits. It is 80 mg/100 mL. There is strong support for reducing it to 50 and it will probably happen in time.
Ireland, Italy and Luxembourg also have a limit of 80.
Some countries have different limits in different states or regions. Or different categories, like "Learners", "P-plate drivers", "HGV drivers" who are set lower limits than ordinary motorists.
As usual it is not the rules themselves which achieve anything but their implementation. There is every indication that this is exceedingly variable from "catching" to "sentencing" to "punishment".
Try adopting the motto "DDD"
Drinking? Don't Drive! or Driving? Don't Drink!
What is Proof?
Proof is another (older) measure of the strength of an alcoholic liquid.
It had its origins in days when a simple test was needed that the liquor did indeed contain a *correct* measure (or more) of alcohol. And it was indeed a simple test.
Some of the liquor was poured over a little gunpowder and ignited. If the alcohol content was adequate, then it would burn 'just right' with a steady blue flame and eventually ignite the gunpowder. If there was insufficient alcohol then it would fizzle out and the gunpowder would be too wet to burn. The 'just right' condition 'proved' the liquor and it was declared to be '100 degrees proof'.
This simple test was clearly cumbersome to perform and was later replaced by using a specially graduated hydrometer to measure the specific gravity. This was far more objective and allowed precise statements to be made as to how much different it was from being 100 degrees  proof. This gave rise to "under-proof" and "over-proof" measures.
In the US a very simple relationship is defined between 'proof' and %AbV. It is that
proof = 2 %AbV
So, 180 proof (US) = 90 %AbV.

It the UK it was laid down by an Act of Parliament in 1816 that "a quantity of 100 degrees proof liquor would have the same weight as 12/13 ths of the same volume of pure water at 51F." (That is twelve thirteenths)
100 proof (UK) = 57.06 %AbV
200 proof (US) = 100 %AbV = 175.25 proof (UK)
100 proof (US) = 50 %AbV = 87.6 proof (UK)
These conversions are handled in the
AbV and Equivalent Values
Keep your powder dry (or wet it with the right stuff!)
At one time (in the days of sailing ships, cannons and gunpowder) the makers of Plymouth Gin distilled a special gin for the Royal Navy. It was 57%AbV or 100 degrees proof. Why?
In order to keep it secure it was stored in the magazine close by the gunpowder. So, even if it leaked and wetted the gunpowder, at 100 degrees proof the gunpowder would still explode.
Though that need has been long gone, they still market the stuff!
Alcohol and Calories
Bad News? Alcohol does contain Calories.
The energy content of pure alcohol is 29.3 kilojoules per gram. That is equivalent to 7 kilocalories. (1 kilocalorie = 1 Calorie of diet)
So there are 7 Calories in every gram. That is about 5.5 in every mL.
In a 75cL bottle of wine of 12% AbV we know it has (0.75  12  10  5.5 =) 90 mL of alcohol which is 495 Calories. At 6 glasses to the bottle that means just over 80 Calories to a glass. There are a few Calories in the rest of the liquid but usually not enough to bother with, though sweet wines (e.g. sherry) certainly have more.

Good News? They may not count!
In the latter part of the 90's interest was shown in determining how these Calories affected us in dietary matters. Assuming the drinking is done in moderation (say 2 or 3 glasses of wine per day) it seems that the alcohol does NOT have any affect at all in terms of putting on weight. The correctness of this conclusion and why it should be so is a matter for a lot more research. But note that it only applies to WINE.
BEER is a different matter. The total Calorie content there can be as much as twice the Calorie content of the alcohol on its own. This is particularly true of the stronger beers (say 5 or 6 %AbV), but less so for the medium beers. It is even possible to find 15 Calories in 100 mL of a non-alcoholic beer. But these *extra* Calories do contain some nutritional ingredients (which is not true for alcoholic Calories). That famous "brewer's paunch" has to come from somewhere!
A Personal Audit
Only for those who want to know!
If you really do want to know just how many units of alcohol you are taking into your body, do an audit. You may be surprised to find just how many you do actually consume. Of course you may choose to change nothing, but at least you know. And perhaps you may cut back one day, but not just yet!
How you do the audit is up to you, and will have to be adapted to your drinking habits. Are you a home or an away drinker, or both? Are your drinking habits regular or irregular?
The easiest audit to do is for the home drinker with a settled routine, and it is that case which is described here. Amend to suit.

First gather together samples of the containers used for the various drinks and establish their sizes.
This is best done using a kitchen measure and water. To gain as much accuracy as possible (especially for smaller ones) fill the container to its working/drinking level and pour it into the measure several times, counting them, until the measure has a reasonable quantity in it. Then divide that reading by the number of times the container was tipped in.
For instance, a liquer glass might need to be filled and poured out 10 times just to get a total reading of 300 mL and a glass size of 30 mL.
Next, find, and note, the %Abv of the different drinks.
Then, draw up a table on the lines of the one below. One of the alcohol calculators might be needed for the last column.

Large Wine Glass175Red Wine152.6
Large Wine Glass175White Wine122.1
Small Wine Glass125Red Wine151.9
Small Wine Glass125White Wine121.5
Half Bottle375Red Wine155.6
Third Bottle250Red Wine153.8
Half Bottle375White Wine124.5
Pint Beer52.8
Liquer Glass40Liquer401.6

Now at any time we can write out an audit, like this:
Sunday lunchHalf-bot.White
Monday lunch
2 Cider
Tuesday lunch2 Cider 2.42.4
Wednesday lunch2 Cider 2.42.4
Thursday lunch
2 Cider
Friday lunch
Pint Beer
Saturday lunch
2 Can Beer
Weekly Total38.8
It is 10 units more than the UK *official* recommended weekly intake. Which is a 37% increase.
And that from someone who considers he is a moderate drinker!
Perhaps he could declare himself an honorary citizen of Australia where it would only come to 30 units. Or (even better) the USofA to get down to 22 units?


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