Some eggnog is aged in the fridge for a month, allowing time for the booze to break down the proteins. The result is a less fluffy concoction that goes down easy. Of course, I went a step further and aged mine for a year and lived to blog about it.
If you choose to age it, follow the guidelines that bartenders use. Use pasteurized eggs. You can also buy dairy with a far-off expiration date, store the eggnog at 45 degrees and serve it before the dairy’s expiration date. Here is the tough part: You can’t open the jar for a taste and try to seal it again. It has to be sealed tightly until day-of-drinking. (If you wanna geek out on this topic, here’s a defense of aged eggnog.)