It's eight o'clock on Christmas morning and we're already onto our second bottle of Champagne. It's a family ritual. Opening presents, scoffing panettone, guzzling the bubbly. Happens every year. And because it's Christmas, and because it's a family ritual, none of us thinks twice about the fact we're drinking at dawn.
Funny, isn't it? If I popped the cork on a bottle of fizz at 7:30am at any other time of the year, my wife would accuse me of being a hopeless alcoholic. Again. And she'd probably be right. But somehow our family - and many others I know - have decided that boozing at breakfast is perfectly okay on Christmas Day. (Indeed, my wife is one of the staunchest defenders of the ritual.) It's far from the only example of how complex and often contradictory the rules can be about when and where it's fine to drink.
Sip pinot from fine crystal at the dinner table and everyone thinks you're sophisticated. Sip pinot from plastic cups on a park bench (come on, we've all done it) and everyone thinks you're a plonko. Same wine, same person; different setting, different assumptions.
Pass around the hip flask of single-malt at a funeral on a cold winter's day and you're a legend. Try the same at the office next Monday and you'll be fired. Drinking vodka before midday is bad for you; mix it with tomato juice and Tabasco and suddenly it's bloody good for you.
In many ways the guidelines about when to start drinking are culturally determined. There's a tradition in this country, for instance, of pubs opening early for thirsty hard-working blokes. Think of the classic Carlton Ale ad featuring a whiskery bushman nursing a glass at the bar with the tag line: "I allus has wan at eleven". It's an enduring image - although most Australians now, I suspect, consider 5pm, not 11am, the acceptable boundary between the working and the drinking day.
The guidelines are flexible, though. Most Australians on holiday would bring that line forward: how often in some exotic location have you heard, at the stroke of noon, someone jauntily announce: "Right, the sun's over the yardarm - who's for a G&T?" And how many times has that someone been you? Acceptable start times for drinking - and tipples of choice - vary from country to country.
In roadside bistros in northern France, for example, truckies commonly wash down breakfast galettes - egg, cheese and ham-stuffed buckwheat crêpes - with glasses of moderately alcoholic local golden cider. And it's not uncommon for their Italian counterparts to add a shot of grappa to their morning coffee order.
Hungover Danes are partial to a breakfast glass of Gammel Dansk, a Jägermeister-like bitter liqueur, which, according to the label, is "Enjoyable in the morning... hunting or fishing". In Barcelona, the old Sunday pre-lunch habit of drinking a glass of local vermouth is enjoying a renaissance - and not just on a Sunday. And the Italian mid-afternoon habit of having an Aperol or Campari Spritz has become enormously fashionable around the world in the past few years.
The English do mid-morning and mid-afternoon drinks particularly well. Elevenses (a marvellous institution) simply must, if you're observing the ritual properly, include a glass of dry sherry or Madeira - especially if you're serving seed cake (which you should). And British wine expert Michael Broadbent, renowned for tasting more great old bottles than anyone, has frequently extolled the virtues of a low-alcohol, sweet Italian moscato to keep one company during the slow hours between lunch and dinner.
Then there's the question of late-night drinking. Again, it's all about context. If, after an abstemious night in, you decide at midnight to crack open a tinnie of pale ale, the accusations of alcoholism would come thick and fast - even though you're well within what health professionals would consider safe drinking limits. But if you've just finished a wine-soaked dégustation and partake in a cleansing ale it's socially acceptable - even though you exceeded the safe drinking limits hours ago.
You could, of course, just follow the example set by chef Fergus Henderson of London's St John, a great believer in both the preventative and curative effects of the notoriously bitter Italian digestivo, Fernet Branca, who recommends a small glass last thing at night and first thing in the morning.
Especially if you're going to tuck into Champagne over breakfast.