Eggnog

One US cup of eggnog weighs 254 grams. Going the other way, 100 grams is about 0.39 cups.

Also called eggnog, egg nog, commercial eggnog, holiday eggnog, traditional eggnog, dairy eggnog.

One cup of standard commercial eggnog weighs about 254 grams (1.074 g/mL), a bit heavier than whole milk (242 g/cup) or half-and-half (242 g/cup) because added sugar and egg yolk solids raise the density beyond what fat alone would produce. Multiple USDA records (FoodData Central generic 'Eggnog' at 254 g/cup, 'Eggnog, regular' at 256 g/cup, Home and Garden Bulletin No. 72 at 254 g/cup) converge tightly at this figure for non-alcoholic commercial dairy eggnog.

Commercial eggnog is a dairy blend of milk, cream, egg yolks, sugar or corn syrup, natural and artificial flavorings (typically nutmeg, vanilla, cinnamon), and stabilizers (guar gum, carrageenan, mono- and diglycerides). FDA does not define a standard of identity for eggnog the way 21 CFR § 131.110 defines milk, so commercial products vary somewhat in composition: fat typically 6-8%, added sugars 12-18%, egg yolk 1-2% by mass. Southern Comfort Traditional Eggnog, Organic Valley Eggnog, Hood Golden Eggnog, Turkey Hill Original Egg Nog, Borden Egg Nog, and most other US retail brands sit within this range and match the 254 g/cup figure for physical density.

Producer nutrition labels systematically understate eggnog's true density because of an FDA labeling convention rather than a measurement of the product. Southern Comfort's label states the serving size as '1 cup (240 mL) = 240 g,' and most other brands do the same. This is the 21 CFR § 101.12 reference amount customarily consumed for beverages, which treats fluid milliliters as if they were grams. If you actually weigh 240 mL of eggnog, it comes to about 258 grams (240 × 1.074), matching the USDA measurement. This is a milder version of the same fluid-ounce-as-mass-ounce labeling artifact seen more dramatically elsewhere (King Arthur listing cream at 8 fl oz = 227 g, for example). Neither the FDA convention nor the KA chart error is a measurement — both treat volume units as mass units. For weight-based recipes, use the 254 g figure, not the label serving size.

Product variation across the eggnog category is real and worth understanding when choosing a substitute. Regular commercial eggnog (this entry) runs 1.07-1.08 g/mL and 254 g/cup. Light or low-fat eggnog reduces cream and sugar; density drops closer to milk, roughly 245 g/cup. Alcoholic pre-mixed eggnog (rum-based holiday products, some higher-end offerings) has spirits added, which lowers density substantially because ethanol is 0.79 g/mL; USDA's 'Eggnog, alcoholic' record measures 240 g per US cup (1.014 g/mL), close to water. Non-dairy eggnog products (Silk Nog on soy or almond base, Califia Farms Almondmilk Nog, So Delicious Coconutmilk Nog, Elmhurst Milked Cashews Nog) build on a plant-milk base and range 240-250 g/cup depending on how much fat and sugar the formulation adds; these are distinct products with their own density profiles.

Homemade traditional eggnog varies with recipe. A classic ratio (equal parts egg yolk, heavy cream, whole milk, with sugar around 15% and spirits around 20% by volume) produces a beverage that runs 1.02-1.05 g/mL, lighter than commercial versions because spirits displace sugar and dairy mass. Aged eggnog (weeks or months in the refrigerator, a traditional practice) does not change density meaningfully; the mechanism is flavor development and mild alcohol-driven pasteurization, not compositional change. For recipes calling for eggnog as an ingredient (French toast batter, eggnog cake, bread pudding, custards, panna cotta, holiday ice cream), commercial regular at 254 g/cup is the anchor most published recipes assume.