Winter beers are more than a marketing whim. Barley sown in winter and harvested early the following September needs about six weeks of 'dormancy' and up to 10 days of steeping, germinating and drying to become malt. Brewing can then begin in late October, and the beer will be mature in November for drinking in December. The timetable, which dates to the days of the farmer- brewers, remains much the same today.
Most winter beers are accented towards the sweet, sustaining malt - rather than the dry, appetising hop - usually with a good belt of alcohol to create at least the pleasant illusion of warmth.
Of the more than 200 breweries in Britain, about 130 are offering a winter special this year. They range from the Ancient Druids pub in Cambridge, which makes a malty draught ale called Frostbiter, to John Willie Lees, the local brewery in Middleton, near Manchester, with its creamy, delicious, vintage-dated 1992 Harvest Ale in the bottle; from St Austell, in Cornwall, with its sweetish draught Winter Warmer, to Borve House at Ruthven, Tayside, with its wood-aged, whiskyish, Extra Strong, again in the bottle.
Some even make two seasonal brews: one specifically for Christmas, the other to see us through the winter. You could argue that Fuller's of London has no fewer than three winter ales. This brewery, which seems to have become a specialist in the field, used to make a strong dark ale for the season, but it was metamorphosed into a Winter Bitter in 1969, and was renamed ESB in 1971.
This famous Extra Special Bitter proved so popular that it was soon made available all the year round, though that does not dilute the pleasure of such a pint at Christmas.
If any other ale so deftly balances the sweetness of the barley malt, the dryness of the hop and fruitiness of the yeast, I have yet to find it.
It is the particular procedure in the last stage, the drying, that defines a malt's taste. The principal malt in most English bitter is slowly 'cured' to create a biscuity character. But Fuller's is one of the breweries that also uses malt 'stewed' to a sweeter, crystalline, nutty flavour.
Like most of Fuller's ales, ESB starts from a grist comprising about 90 per cent barley malt, the rest being maize and a tiny amount of sugar and caramel. Maize lightens beer, though the percentage used by Fuller's seems so small as to be barely significant. British brewers began to use sugar during the colonisation of the Caribbean. It lightens beer, and can impart a slightly rummy taste.
Fuller's hops come from Kent, Worcester and Hereford, and the water it uses is fairly low in bicarbonates and higher in chlorides, making for a fuller flavour. The yeast the brewery has used for at least 50 years seems to impart a honey-flower character.
These ingredients, and Fuller's vessels, do not differ greatly from those for many other British ales, the magic is in the skill and style of the brewer. In some respects the making of beer is a form of cooking: even with the same ingredients and recipe, two chefs can produce different results.
When ESB lost its seasonal exclusivity, Fuller's came up with Mr Harry, an ale named after an imaginary connoisseur. It contains no sugar or maize, and has a higher proportion of 'crystal' malt, making for a specially sweet, nutty flavour. Mr Harry, which began as a bit of fun to brighten the winter months, has become a seasonal fixture.
This year, the good news is that Fuller's is offering on draught its extremely strong Golden Pride 'barley wine', usually available only in the bottle. The bad news is that this beer is on sale - from next week - in fewer than 20 pubs, all in the South-east, and in tiny quantities. Some of the publicans are even proposing to conduct draws to determine which customers will be allowed a glass.
I think great beers are insufficiently prized, and applaud this stroke of anti-marketing. Of course, such sentiments come easily if you live near, for example, the Rossetti in St John's Wood, London, the Flowing Spring near Reading, or The Boat at Berkhamsted, in Hertfordshire.
Which is best, the draught or bottled? It depends on personal taste, but the distinction becomes much more evident at the stronger end of the range. The draught barley wine pours relatively flat, and has a pinkish- russet, rather than golden, colour, a huge, malty-nutty bouquet and palate, a leafy hop taste and warming alcohol in the finish.
It is astonishing how much colour is lost in filtration for the bottled version. It is much paler, somewhere between golden and bronze, and seems to have a drier, more flowery hoppiness. Bottled beers require much more carbonation to protect them from staleness through oxidation, and the bubbles not only deliver a tingle but also carry the hop flavours to the nose and tongue.
In considering such delights, one has to be aware of their alcoholic power. An ordinary bitter contains about 3.5 per cent alcohol by volume. Fuller's Mr Harry has 4 to 4.5 per cent, the renowned ESB 5.5 per cent, and Golden Pride barley wine just over 9 per cent (still less strong than most grape counterparts, though they tend to be consumed in smaller servings).
Drinkers with a serious understanding of ESB are inclined to stick at one pint, at their local, and not to drive home. The barley wine I like to have in a burgundy glass. It is an utterly English accompaniment to a roast- goose Christmas dinner.