In Episode 54 of the Vlog, Jane gives Rochester a glass of eggnog and he takes a sip. He immediately complains that it has no rum and thus isn’t consistent with his version of eggnog. He does have a point. Eggnog is a rich, chilled, sweetened, dairy-based beverage. It is traditionally made with milk, cream, sugar, whipped egg whites, and egg yolks (which gives it a frothy texture, and its name). In some contexts, distilled spirits such as brandy, rum, whiskey, or bourbon are added to the drink. While brandy is the most traditional add-in for eggnog, according to most recipes, experts recommend a mixture of dark rum and cognac. If you like your eggnog a little stronger, you can also add bourbon, though experts recommend sticking to rum and cognac to preserve the 'nog's flavors.
Throughout Canada and the United States, eggnog is traditionally consumed over the Christmas season from late November until the end of the holiday season. The first printed mention of Eggnog was in 1788 in “The Jersey Journal” that referred to a young man drinking a glass of Eggnog.