It could have been decided that a unit was equal to an ounce or something else in imperial.

The problem isn’t with the name, it is with the products that don’t come in rounded metric sizes. For example, one can calculate that a “pint” of beer contains 56.8 “units” of beer. Now if the alcohol content was 5 %, the difficulty in estimating the amount of alcohol becomes difficult so no one bothers to figure it out. A quick estimate would be that 10 % would yield 5.68 units of alcohol, so 5 % would be half of 5.68 or 2.84 units.

It would be simpler to calculate 5 % of 600 mL and get 3 % or 5 % of 500 mL and get 2.5 %.

So, if there is a difficulty, then the solution should be to change the legal amounts of dispensed alcohol to rounded metric sizes.

E.g. with beer marked as alcohol: 4 ml per 100 ml, it would be effortless for just about anyone to work out that a 500 ml glassful contains 20 ml (or 2 cl if you prefer).

I know this amounts to the same thing but it wouldn’t demand that the consumer understands percentages. Presumably the practice of labelling nutrion information as per 100 g is for the same reason.

‘A 500 mL container with 500 mL beer, with alcohol content of 15 mL/3 % is a bit clearer than 500 mL with 3 cL.’

However, I am quite concerned about the introduction of the metric prefix, centi, into a context where it would be used everyday.

I have studied the progress of metrication attempts all around the world, and in many different industries, where I have observed that the use of the metric system prefix, centi, in the unit centimetre very dramatically delays the success of the metrication process. See http://www.metricationmatters.com/docs/centimetresORmillimetres.pdf

I have not specifically studied the places where centilitre is used, but on the basis of the enormous delays with centimetre I would not recommend its use without considerable study – and even then I would require massive evidence of its speed of adoption and of its non-transference to other industries – centilitres of oil, paint, or vinegar, are examples – before I could recommend its use.

Pat Naughtin
Geelong, Australia

500 mL beer, with alcohol content of 15 mL is a bit clearer than 500 mL with 1.5 cL. Of course its the same amount either way but its muddling up the magnitude of the units. It would make more sense to have 50 cL and 15 mL. No one says 10,000 m give or take 2 km do they? Maybe 10 km give or take 2000 m.

A 500 mL container with 500 mL beer, with alcohol content of 15 mL/3 % is a bit clearer than 500 mL with 3 cL. Of course its the same amount either way but its muddling up the magnitude of the units. It would make more sense to have 50 cL and 30 mL. No one says 10,000 m give or take 2 km do they? Maybe 10 km give or take 2000 m.

The average daily alcohol intake is about 4 units? so thats 40 mL and drinks are sold in mL. Drink two 500 mL beers with 15 mL alcohol content and 30 mL of alcohol has been consumed. Easy enough. No ambiguity.

The spokesman should have went one step further and suggested using mL instead and just forget about units altogether. The whole process could be simplified and made clearer. This is probably one of the reasons why people have no clue what units means and how much they are consuming and probably makes them not even care!