Though few Americans still bother with it, the burning of the yule log was at one time one of the most firmly entrenched customs of Christmas. Everything to do with them was fraught with ritual — certain formulas had to be followed very carefully lest disaster befall the household in the upcoming year.
It was unlucky to buy a yule log. Lucky ones were obtained from one's own land or from a neighbor's wood. Often a stump or a root (not necessarily a proper log at all), it was brought home on Christmas Eve and laid in the hearth.
The first step towards lighting the yule log was fetching the carefully-preserved scrap of the previous year's log from under the homeowner's bed. Having done its job of keeping the house safe from fire and lightning since the last festive season, it was now used to light the new log. The new log had to catch fire during the first attempt at lighting it; its failure to do so was a sign of misfortune coming to the family. Such an important duty had to be handled gravely. And clean hands only, please — to attempt to light the log with dirty hands would have been an unforgivable sign of disrespect.
Once lit, the log had to be kept burning for twelve hours. This was not always an easy task, as special caution was given against stirring the embers during the lengthy Christmas Eve supper. The log could not be tended as long as any scrap of the dinner remained on the table, or while anyone was still eating.
As the log burned, people told ghost stories and tales of olden times whilst drinking cider. Shadows cast upon the wall were carefully scrutinized, for it was well known that a "headless" shadow foretold the death of the person casting it within the year.
Similar to the yule log was the Christmas candle. It too was lit on Christmas Eve, usually just at dusk. Care was taken to keep it burning at least as long as the hosts were still up (if not all night, depending on regional custom). Like the yule log, a proper Christmas candle could not be bought, so grocers made a practice of handing them out to customers. A bit of the burnt-down candle was also preserved from one year to the next as a lucky charm for the household.
A much more popular version of the yule log is available to modern society — the "buche de noel." Rolled, frosted in chocolate, and decorated to look like a yule log, this sponge cake is served as part of the Christmas Eve meal in France called reveillon, which takes place after midnight Mass.