"Of course it's good for you, it's got Red Wine in it!"

Or, why Wine is amazingly good and what's in it.

To make clear why wine is so manifoldly beneficial I'll highlight what's in it that makes it so.
Lets start with the obvious bit - Wine is mostly Water, and of course everyone knows water is essential (to be truly flippant you could say that its technically juice and so one of your 5-a-day). In your average bottle there'll be around 85% water. The other 15% or so is what's interesting though.

After water comes Alcohol, both the demon and the angel of this magnificent drink. Legally it has to be over 8.5% to be called Wine, and whilst the average percentage has been creeping up over the passed 30 years (predominately due to better viticultural practises, such as picking later, and better vinification, like using the right strains of yeast) most wine sits around 13%. Alcohol is angelic purely because its a depressant, it depresses those parts of your brain that control prudence and embarrassment and make for a wonderfully relaxing fun time. Demonic for much the same reason, it depresses the brain further inhibiting reason, sense of responsibility, sense of decorum and ultimately sense of coordination. Recently thanks to the wonders of science there have been several excellent contradictory studies showing that alcohol is both good for you and bad for you, in moderation and in excess. As with many things the best advice is "little and often" (As a small aside, often is the key, as your body produces Alcohol Dehydrogenase to break down alcohol as soon as it enters your system. If you keep your ADH topped up, you break alcohol down more efficiently and thus more healthy.)

As well as alcohol, the key ingredient that makes wine work (especially in regards to accompanying food) is Acidity. Generally wine will have a pH between 3 and 4 (7 is neutral for those of you who didn't do the litmus-test in school). Acidity is key in making wine refreshing and cleansing, it causes the tongue to salivate and helps cut through fatty and rich dishes.
There is an interesting interplay between acidity and sweetness, that is often not appreciated.
Sugar is less of a factor in wines these days than in the passed centuries, when most wine had over 50 grams per litre. Today nearly all wine drunk is dry, that is with a residual sugar level of under 4g/litre (to give you an indication of sweetness in common drinks, Coca-cola has 114 g/litre, it doesn't feel massively sweet due to the high acidity). Without a high acidity wine would feel flabby and sickly.
Tied in with sugar is Glycerol, and technically more abundant than both sugar and acidity combined. Glycerol is a by-product of fermentation and originally comes from the sugar in the grape juice, thus wines from the new world, where grapes are riper and have higher sugar tend to have more. Its a key component as it gives wine weight and body, the viscosity (as I always say to my trainees when asked how full bodied a wine is: does it feel more like water or milk in the mouth).

Finally, Tannins (although mainly in red wine), are the last essential component in a good glass. Tannins come from the skin and stalk of the grapes and give that drying-of-the-tongue-and-gums sensation (for those too embarrassed to ask but always wanted to know: White wine is made by fermenting just the juice of white/grey skinned grapes, whilst Red wine you leave the crushed grapes in; hence white wine not having tannins). The reason why tannins are so cunningly useful is that they bind with protein molecules upon contact, such that when you have a good steak they help tenderise the meat, while the meat helps the wine seem less harsh. (Additionally as a wine ages the tannins bind with colour compounds, like reservatrol, and fall out of solution, which is why you get sediment in old red wine and why the wine looses it's colour).

What's left in the bottle besides the above, are flavour compounds or phenolics, trace elements such as iron and sodium, and sulphur dioxide. Now poor SO2 is the latest in a long line to get the media bashing, and the greens up in arms, as some people are allergic to it. It is an essential element in wine-making. Firstly, without it you cannot make wine and secondly it is naturally produced in wine-making. Mostly it's been blamed for "That terrible headache" you get the following morning. Let me be the first to say that this is complete horse-shit! Dehydration and methanol are what cause headaches, and although I have no evidence to back up this claim I firmly believe its the quality of beverage you consume that affects how you feel afterwards (Consider drinking 75cl of gut-rot cider versus 75cl of Puligny Montrachet 1er Cru). Whilst a move away from high levels of SO2 is naturally a good thing, this was mostly done several decades ago, as wine-technology advanced.

So wine is made from water, alcohol, glycerol, acidity, residual sugar and tannins (with some SO2 to make it drinkable). Really that's it. When people talk of nasty additives and natural wine they don't have a clue.

Fill ev'ry glass, for wine inspires us,
And fires us
With courage, love and joy.
Women and wine should life employ.
Is there ought else on earth desirous?
John Gay The Beggar's Opera 1728

Suggested wine-style to try this week: Dry Fino Sherry (since we're continuing backwards with what's been in vogue - Sack, as the Elizabethans called Sherry)

As an aside, the latest Health Office way to bully people into stopping drinking is calorie counting; so good news ladies its all a lie.