It is in the writing of one of Thomas Sutherland’s (1772-1850) great-nephews that I found the account of this family tradition, which the great-nephew maintains was practiced by all Sutherland men going back several generations, including Thomas. Here he describes his own father’s version:
As the midnight hour of the last day of the year approached he proceeded to prepare a decoction known as the Egg-Flip. He had a large pot brought from the kitchen to the dining-room fire and into this he poured the contents of several bottles of beer, a bottle of stout, and a half-a-dozen eggs, which he had beaten up. After simmering for a while, and being allowed to reach almost to the boiling point, a few glasses of whisky were added, then the whole was poured into large jugs and ready for consumption by those who cared for it. We boys hated it, which is not surprising; and our guests—for a few neighbours always popped in—while professing to think it excellent, never partook freely of it. The result was that almost all the stuff had to be thrown out, but this fact did not deter my father from repeating the process year after year, with the same invariable result. Even the additional fact that in the process of manufacture the hearth rug was almost always, much to the distress of my mother, seriously damaged, did not suffice to stop the custom, which was certainly one to be more honoured in the breach than in the observance.
As a beverage, the Egg Flip can be dated back to the late 1690s apparently, and enjoyed some popularity in the Victorian era. More reliable recipes are available online, if anyone is interested. But as far as family traditions go, this does seem to be in keeping with earlier descriptions of Sutherland and his well-stocked cellar.