Basic Physics

• The base for almost any ice cream recipe consists of flavored cream, sweetened with sugar and thickened with either eggs -- the classic version -- or with gelatin. The mixture is almost always heated, for a number of reasons. It unwinds or "denatures" the protein molecules in the cream, giving a smoother texture. It also helps dissolve the sugar, and both eggs and gelatin require heat to do their work of thickening the mixture. This means the base is usually hot or at least warm, when it's finished. For your finished ice cream to have the best possible texture, it must freeze quickly, and a well-chilled base helps with that. It's just basic physics.

The Flavor Thing

• One of the reasons for ice cream's enduring popularity is that it's available in flavors to suit almost any taste, from classic vanilla, strawberry and chocolate to exotic options such as bacon-flavored or saffron-flavored. Whatever recipe you've chosen to make, an essential part of the process is infusing your flavors into the base mixture. For example vanilla beans must be simmered in the cream, while flavoring extracts are added late in the process after the base is cooked. In either case, letting the base rest and cool before it's frozen gives the flavorings extra time to infuse throughout the base and improve its taste.

The Egg Thing

• Classic ice cream recipes are made from a custard base, thickened with whole eggs and extra egg yolks. These are among the richest of ice creams, and it's the yolks that give French vanilla ice cream its characteristic pale yellow color. Most recipes for egg-based ice creams recommend refrigerating the base overnight before churning, though few explain why. The emulsifiers in the egg yolks continue to work as the custard sits, binding the fats and liquids together in a smoother texture. It's not always detectable by taste testers -- it's good ice cream, either way -- but the aged base will usually freeze to a lighter, smoother texture.

Finishing the Job

• If you have an ice cream maker, the final freezing is a simple process. Models with built-in refrigeration only need to be plugged in and turned on. Lower-cost models use a gel-filled reservoir to freeze the ice cream by contact, with a manual or motor-driven paddle scraping the frozen custard from the sides of the unit. Without an ice cream maker, you can simply freeze the base in a shallow bowl or container. It will be dense and hard, but you can lighten it by processing it for a few seconds in your food processor. Alternatively, beat it in your stand mixer with a chilled bowl and paddle. Either technique adds air, lightening and softening the ice cream.