The tradition of setting fire to the Yule Log dates prior to the medieval times. It initially used to be a Nordic tradition. The name of the old Winter Solstice festivals in Scandinavia is Yule. The same is true for other parts of northern Europe, for instance Germany.
Primitively an entire tree that was chosen cautiously, the Yule log was brought into the house with great celebration. The biggest extreme of the log would be fixed into the fireplace whilst the rest of the tree stuck out towards the room. The log was to be set alight from the remnants of the previous year's log which had been cautiously put away and gradually fed into the fire throughout the Twelve Days of Christmas. It was vital that the re-lighting process be done by someone with neat hands. It is very difficult to burn a tree nowadays since most people have central heating.
In case of Provence, France, it is customary that the whole family aids in cutting the log down and that a small portion is burnt every night. If any portion of the log is remaining after Twelfth Night, it is kept safely in the house for one year until the next Christmas. This is done to protect against lightning. This was also done in some parts of Holland, but the log had to be kept underneath a bed. The log was chopped down on Christmas Eve morning and set alight that evening, in some eastern European countries.
In the UK, in a place known as Cornwall, the log is named 'The Mock'. The log is dehydrated and then the bark is chopped off it before it comes inside the house to be scorched. Also in the UK, Coopers, the traditional name for barrel makers, provided their customers old logs that they could not utilize for constructing barrels for Yule logs.
The tradition of the Yule Log advanced all over Europe. Different types of wood are used in different countries. Oak is traditional in English. For Scotland, the wood is Birch, while it’s Cherry in case of France. Also, in France, the log is moistened with wine, prior to getting burnt, so that it gives off a nice fragrance when lit.
Some people possess a significant bunch of Ash twigs instead of the log, in Devon and Somerset in the UK. This comes from a local myth that Joseph, Mary and Jesus were extremely cold when the shepherds acquired them on Christmas Night. So the shepherds got hold of large bunches of twigs to set fire to and keep them warm.
Instead of a log, in some parts of Ireland, people have a large candle and this is only set alight on Twelfth Night and New Year's Eve.
Different chemicals can be smeared on the log like wine to make the log burn with different aroma and different colored flames.
The Yule log’s ashes are supposed to be very good for plants. This is a fact, because the cinders from burnt wood contain a lot of 'potash', which helps plants grow and bloom. But if you get rid of the cinders on Christmas day, it is considered to be very unlucky.
A 'bûche de Noël' or Chocolate Yule Log is now a famous Christmas pudding or dessert. It's commonly eaten in Belgium and France, where they are known, in Flemish, as 'Kerststronk'.
They are formed of a chocolate sponge roll coated with cream. The outside is covered with chocolate icing or just chocolate and festooned to appear like a bark-covered log. Some people like to put additional ornaments, for instance marzipan mushrooms.