I LOVE EGGNOG!
Ingredient lists omit the physical behavior of starches under varying moisture loads. Instant vanilla pudding relies on modified food starches that set rapidly when exposed to cold dairy liquids. Substituting heavy cream for milk alters the fat-to-protein ratio, yielding a denser mouthfeel but slowing down the initial thickening phase during the two-minute whisking window. Similarly, using commercially pasteurized eggnog introduces stabilizers that prevent curdling, whereas raw farm-fresh holiday beverages can separate if not tempered correctly with additional dairy.
Preserved baking components offer predictable hydration rates. Instant pudding mixes absorb exactly the amount of liquid specified because manufacturers pre-hydrate and dry the starches for uniform performance. Conversely, substituting homemade caramel sauce for individually melted caramels changes the moisture content at the base of the crust. Liquid caramel introduces extra water that can soften the graham cracker crust prematurely. To maintain structural integrity when substituting fresh components, reduce added liquids by one tablespoon for every half-cup of high-moisture additions.