The Nog Before

• Cooked egg nog features the same ingredients as the raw version -- eggs, sugar, salt, vanilla and milk. The cooked version requires adding the mixture to a pan and gently heating it -- without boiling -- until it's thickened. The egg nog is cooked and safe when the liquid reaches 160 degrees F, according to the American Egg Board. Once cooled, add vanilla and cold milk to the mixture. The mixture is then ready for the refrigerator and will store safely overnight to enjoy the next day.

The Alcohol Factor

• If you're making non-alcoholic egg nog, then cooking the eggs is the safest way to make the drink. Keep in mind, however, that adding alcohol to the recipe doesn't automatically make it safe. If you cook it the night before and add alcohol, you still need to properly store and refrigerate the egg nog to avoid the risk of food poisoning.

Drink It Soon

• You may store homemade egg nog in the refrigerator for two to four days before it goes bad, according to the government's Food Safety website. The mixture isn't suitable for freezing. If you prepare your cooked egg nog the night before, then serve within the next couple of days. The closer to party time you can make your egg nog, the better. You may find that the quality and texture deteriorates after the first day.

Fresh Eggs and Refrigerators

• When making egg nog, ensure that you use eggs well within their expiration date. Discard cracked eggs, and always store eggs at home in a refrigerator set lower than 45 degrees F. When you take your cooked egg nog out to serve, pour only what you plan to serve soon and refrigerate the rest. Egg nog left at room temperature for two hours or more can quickly become home to potentially harmful bacteria.