The news is buzzing with alcohol advice.

The Tories want to make drink labelling clearer, getting rid of the ubiquitous 'unit' and bringing in the maths. The World Cancer Research Fund has advised that drinking lower alcohol wine (at around 10%) could reduce the risk of getting related cancers by 7%.

It is all a confusing muddle for us drinkers. For example why does a few percentage ABV's either way make so much difference to my intoxication and therefore health? We have all had that slightly 'other' mushy head feeling after drinking a small glass of 14.5% ABV wine, which just does not seem to happen with 12% ABV. Can 2.5% make all that difference? Do people even bother to look at the strength of wine, especially as the alcohol percentages on bottles are rendered in a small window of intervals making them seemingly meaningless anyway?

So lets try and work out some practical examples of inebriation and how it affects us.

I pour a 175 ml glass full of 12%ABV wine (perhaps a nice Beaujolais or German Riesling)

Down the hatch...well moderately over 20 mins.

First of all ABV means Alcohol by Volume. Which in turn means the amount of alcohol (ethanol) mixed up in the essentially skillfully flavoured water that is wine. So 12% of my glass of flavoured water (err wine I mean) is alcohol.

Next we are familiar with the term 'unit' of alcohol. It actually means 10ml of alcohol (the Tories propose changing the term 'unit' to centilitres of alcohol as one unit is 1cl)

So how does that relate to my glass of wine?

Well to work out how many millilitres of alcohol are in my glass is easy. 1 litre of wine at 12 % ABV contains 10 x 12 ml (always 10 x the ABV) of alcohol which makes 120ml. So my 175 ml glass contains 0.175 x 120 which is 21ml.

There we have it, 21 ml of alcohol in my glass of wine (2.1 units)

To put that into context a small carton of Ribena is about 200ml, so about a tenth of that, or indeed a third of a 65 ml Yakult, which you may well need the following morning. Basically a small slurp of pure ethanol.

Let go a bit further, into the human body.

In about 30 mins the 21 ml of alcohol will be in my blood. This is where measurements get confusing. The BAC (Blood Alcohol Concentration) is measured in milligrams per 100 ml of blood. The quantity of alcohol that is in half of a Ribena carton sample of our blood (if I am not careful I may put you off Ribena for life). We need to get out our imaginary scales.

10ml of alcohol (1 unit) is 7.9 grams. So we divide our 21ml of alcohol by 10 and multiply by 7.9. This gives us 16.59 grams of alcohol coursing around our blood stream.

Roughly 10 grams of alcohol increases the BAC of an average person (whoever that is) by 20mg/100ml of blood.

So hey presto I have 16.59 grams in my blood, which equates to approx 33mg/100ml.

Finally.

Lets wait until all the alcohol has flushed from my system, at a less than impressive unwavering speed of 15mg/100ml blood per hour. So at least two hours of abstinence.

Now break open a 14.5% bottle of wine (perhaps a New World Pinot Noir or Old World Rhone) and pour into the same 175ml glass (obviously washing out the old wine dregs with water first as I do not claim to be a master blender)

Same calculation leaves us with 25.4 ml of alcohol in the glass which will lead to an 21% increase in the amount of alcohol in my blood compared to the 12% ABV wine.

This is 20.1 grams which equates to approx 40mg/100ml blood.

To fully see the implications of this difference from 10%ABV wine to 14.5% ABV wine, imagine we had two 175ml glasses of each at different times and compared -

2x 175ml glasses of 10% ABV wine = 35 ml of alcohol or 55mg/100ml blood
2x 175ml glasses of 12% ABV wine = 42ml of alcohol or 66mg/100ml blood
2 x175ml glasses of 14.5% ABV wine = 50.8 ml alcohol or 80mg/100ml blood

You can see the small ABV% difference has massively increased the BAC (Blood Alcohol Concentration for those of you that have had a drink to get you through the maths and cannot remember me expanding it before). You do not have to travel very far up the BAC scale to feel the effects of alcohol. Certainly at 50mg/100ml the word squiffy comes to mind, but I am a bit of a lightweight. Here is a good explanation of the progressive effects.

The drink drive limit in the UK is 80mg/100ml of blood, but I would not risk getting behind the wheel after two glasses of any wine.

If the Tories manage to get into power and make these labelling reforms, I hope they issue everyone with a comprehensive calculator. As I have demonstrated (I hope), it is a little complex to unravel.
It sounds like the World Cancer Research Fund has taken the stance that making people drink less is impossible, but changing the alcohol content and hopefully achieving the same thing is. I suppose there is a fine balance between 'other ' health benefits of drinking wine in moderation and the health risks. Of course we may just drink more to get round the lack of 'punch' if that is what we want from wine.

I am all for less alcoholic wines on the market. I am slightly fed up with the proliferation of big boozy bottles. We almost forget what wine is all about, the ethanol muddles up our heads before we can really appreciate it.

So what is 'proof' anyway?

18th century sailors who were paid in rum would 'proof' it by pouring the stuff on their gunpowder. If the gunpowder still burnt well then the rum was considered good enough as it was not too 'watered down' or 'under proof'.

Whereas I am keen on their being more variation of 'under proof' wine on the market, lets hope our choices are not all eventually too 'watered down', as where is the fun in that. Variety is the spice of life (much like a big Rhone).

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