What exactly is One Serving or Unit of Alcohol?
Alcoholic beverages are kind of funny when it comes to serving sizes and measurements, and there does seem to be a persisting belief that all drinks containing alcohol contain the exact same amount of inebriant. To many, a glass of wine, a glass of scotch, a glass of alcopop, and a glass of beer will all have the same effect, and this can and does quite often lead to disastrous results.
After downing a glass of hard liquor, a person might claim “I’m not drunk, I’ve only had one drink”, but their behaviour and blood alcohol levels will beg to differ. Likewise, a person who is naive about alcohol may emphatically state “I’m so wasted, I’ve had an entire glass of beer” and may delude themselves into thinking that they are indeed drunk.
There is a lot of confusion in the media and in the general public about what constitutes “one serving” of alcohol, and the confusion gets even worse when some official organizations start talking about “units” of alcohol. Here we will define exactly what one “serving” and one “unit” mean so that you can make wiser choices when going out with friends or staying at home and enjoying a few drinks in good company.
Alcohol by Volume (ABV) versus Proof
First of all, while it may be common sense to some, one glass of beer does not equal one glass of wine or a glass of hard liquor; each type of drink contains different alcohol content. This is why you won’t feel much if you have a glass of beer but will feel very drunk if you have a glass of undiluted, straight gin or vodka. Beer usually has 4.7 percent alcohol by volume, or ABV. Wine contains anywhere from 11 percent to 14 percent alcohol by volume, and hard liquor such as vodka, gin, rum, and tequila will contain 35 to 40 percent ABV. Some hard liquor and liqueurs will contain even more, with some being up to 54 percent ABV. This means that a glass of rum will contain far more alcohol than a glass of beer or wine.
In the United States, along with the ABV measurement, they will sometimes use the term “proof”, which is defines as being twice the ABV. Hence, a rum that has a 40 percent ABV may also be called “80 proof”. The famous Bacardi 151 is 151 proof and contains 75.5 percent ABV. The high concentration of alcohol is what makes it flammable.
One Serving Measure
One serving or one standard drink of alcohol will contain 0.6 fluid ounces or 17.8 millilitres of pure alcohol. This translates to:
• 12 ounces or 355 mlof standard 4.5 percent ABV beer or wine cooler
• 8 ounces or 237 ml of malt liquor
• 5 ounces or 178 ml of table wine
• 3.5 ounces or 103 ml of fortified wine such as sherry or port wine with a 17 percent ABV
• 2.5 ounces or 74 ml of cordial, liqueur, aperitif or digestif with a 24% ABV
• 1.5 ounces or 44 ml of “hard liquor” with 40 percent ABV such as most commercially available rum, gin, vodka, brandy, and tequila.
One Unit Measure – United Kingdom and Australia
In the United Kingdom and Australia, a unit of alcohol is defined as a measure of the volume of pure alcohol in an alcoholic beverage. In the U.K., one unit is equal to 10 millilitres of pure alcohol, while in Australia one unit is defined as 10 grams (12.7 ml) of alcohol. In Great Britain, the number of alcohol units will be published on the container’s label.
For a healthy adult, 75% of an Australian unit can be metabolized in an hour, and 95% of a U.K. unit can be metabolized in the same amount of time.
If you’re in the United Kingdom, and find yourself in a pub, you can do a quick calculation of the number of alcohol units. For example, a pint of beer contains 568 millilitres. Multiply the volume of the drink by the ABV percent, which, in this case, is 4 % (but keep in mind ABV varies from beer to beer). Then divide the number by 1000.
(568 X4) / 1000 = 2.3 units
Because most beers in the U.K. have an ABV of more than 4 percent, a pint will have almost 3 units of alcohol.
Here are the units of alcohol that typical popular beverages will contain:
• A large glass of wine will contain about 3 units, while a smaller glass (175 ml) will only have two.
• A small glass (50 ml) of sherry will contain approximately one unit of alcohol.
• A 25 ml measure of hard liquor such as vodka or rum will contain one unit.
• A 35 ml measure of hard liquor (common in pubs) will contain 1.4 units.
• Alcopops, which are pre-mixed cocktails consisting of hard liquor/grain alcohol and juice or pop, usually contain 1.4 to 1.5 units of alcohol per bottle.
The government of the U.K. recommends that men drink no more than four units of alcohol per day, while women should drink no more than three.
In Canada, the recommended maximum is two standard drinks per day for men, and two standard drinks per day for women with a weekly total of nine.
In the United States, for both men and women, it is recommended that no more than one standard drink per day is consumed.
In Australia, the government recommends no more than two Australian units per day for both men and women.
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