Egg yolks
Cholesterol-laden home recipes for nog call for six to 12 eggs per quart of milk. This version—which shows up in stores for the holidays—contains far fewer. Based on the total cholesterol content, we estimate that it has just two large egg yolks per quart. Because eggnog contains dairy and eggs, it's regulated by the FDA, which requires commercial nog to contain 1 percent "egg yolk solids."
Carrageenan
Homemade eggnog has a custardy texture (a dozen eggs, remember). But instead of adding more expensive eggs, food manufacturers rely on additives like this seaweed extract to thicken their beverage to a familiar consistency.
Guar gum
This ground-up endosperm of the guar bean is used here as another thickener.
Milk
As we all know, milk can contain colonies of live bacteria that can cause it to spoil quickly. Back in the old days, a bit of alcohol may have helped kill off some of those bugs. (Alas, there's no actual Southern Comfort in Southern Comfort Egg Nog, so you will have to refrigerate.) Hundreds of years ago in pre-refrigeration Britain, milk was sometimes consumed as posset, a potion of milk, eggs, figs, and wine or ale—call it proto-nog.
Cream
The FDA dictates that US nog have at least 6 percent milk fat. Since whole milk is only about 3.5 percent, many manufacturers add a dollop of cream to boost the lipids.
Corn syrup
Early Roman nog-like drinks were often sweetened with honey. Using corn syrup might be a poor attempt to re-create a thick, homemade texture of honey or sugar while simultaneously feeding our sweet tooth. Or it could be a way to save money: Sugar is about 1.4 times more expensive than this stuff.
Spice
Nutmeg is the preferred eggnog seasoning, though there are commercial varieties built around nearly every yuletide spice. (The Southern Comfort-branded stuff, made by US eggnog titan HP Hood, also comes in a vanilla-spiked version. Hood offers pumpkin-, caramel-, and sugar-cookie-flavored concoctions too.) Online reviews note that Southern Comfort nog has clear clove overtones, with at least a touch of cinnamon. In merrie olde England, nutmeg was costly enough to help make a mug of nog an expensive holiday treat.
Natural and artificial flavor
These ingredients likely account for the eggnog's "Southern Comfort" note. According to flavor expert David Dafoe, a whiskey-bourbon taste can be engineered from a mixture of oak extracts (conjuring the oak barrels in which the spirits are aged), a touch of vanilla, and the fruity esters ethyl acetate and ethyl-2-methyl butyrate. How can makers of nonalcoholic beverages like this replicate the "burn" of alcohol on the tongue? A tiny bit of capsicum pepper—just enough to bite, not enough to taste.
Annatto and turmeric (for color)
The use of these two natural food colorings—which add a yellow tone—is technically forbidden in eggnogs under federal regulation (it might make revelers think the drink contains more egg than it really does). But eggnog makers pushed back, and that rule has been stayed—pending a public hearing—for the past 30 years! The FDA is now looking into it.
