Ice cream requires very little other than preparing a simple custard base made up of milk, heavy cream, eggs, sugar, vanilla, and salt, and then churning and freezing it until firm. At least that is what most home cooks think until they turn out ice cream that is marred by ice crystals or doesn’t have the super-rich and creamy texture of artisanal store-bought (or parlor-made) ice cream. It turns out that commercial ice cream makers spend thousands of dollars on churners and fast and powerful freezers that eliminate the problems faced by home cooks, namely ice crystals—the enemy of smooth ice cream.