|Photo from Serious Eats.|
Depending on who you ask, you will hear different accounts of the history behind the so called Christmas beers. The story I heard living in Belgium was that Christmas beers started after WW2. At the end of the harvest period, brewers would put freshly harvested hop into their barrels, together with the remains from the previous season. Autumn providing the perfect temperatures for the fermentation of beer, by December these Christmas beers would be ready to be sold/given as presents to the best customers. Each brewery would of course put its signature into their Christmas beer, adding spices of their liking.
But this story may not fly if you talk to a Brit: he will tell you that British brewers had been making Christmas beers for a very long time, well before Belgians copied this tradition. But then again, talk to Scandinavians, and they will tell you that they invented the tradition: hundreds of years ago, Scandinavians would celebrate Jolner in December, in honor of one of their gods, Thor. In preparation of that celebration, they would start preparing a special drink in September/October, for it to be ready in December. They called this drink Julol.
Personally I am inclined to go with a mixture of these stories: I think the Scandinavians did invent this, although it had nothing to do with Christmas; the British imported the whole affair in the UK, but the Belgians were those who relaunched the whole tradition after WW2. Do I have any ground to think that this is how it went? Nope.
Christmas beers are richer than "normal" beers: denser, more aromatic, spicier, with a higher alcohol content, they are made of two different types of malts. Although there are a couple of "blonde" Christmas beers, the vast majority are dark beers, some of them almost pitch-black.
As many things-Belgian, Christmas beers go strong in the US. The American beer scene is, even to a non-expert like me, pretty impressive: artisanal beers are pretty lively, but Belgian beers are dominating the import markets (+29% in 2011 compared to 2010...). However, next to many traditional Belgian Christmas beers (Delirium Noel, N'ice Chouffe, Fantome de Noel), you will also find American and Canadian Christmas beers that are very, very good.
Christmas beers are a wonderful thing, and make for a beautiful Christmas present, if you are still undecided about what to give. Here is a list of 8 Christmas beers, some Belgian, some North American chosen by the site Serious Eats. I have had a few of them (Fantome de Noel, Mad Elf), and they are very good.