Air is the invisible a-nd cheapest ingredient in ice cream. It makes ice cream softer a-nd creamier. The tiny air cells whipped into the base mix are largely responsible for the general consistency of ice cream, a-nd greatly affect texture a-nd volume of ice cream. The more air bubbles there are a-nd the smaller they are, the smoother the ice cream will be. The word "overrun" is the technical terminology used to indicate how much air an ice cream holds. The finished ice cream must weigh at least 4.5 pounds per gallon, a-nd there must be at least 1.6 pounds of total solids (fat + protein + lactose + minerals + added sugar) per gallon, thereby limiting the maximum amount of air (called overrun) that can be incorporated into ice cream. But because the air is free, a-nd it can increase the volume, some non-premium commercial ice creams could well have an overrun sometimes even exceeding 100 %.

Continue freezer is a kind of ice cream machine be applied to freezing, mixing a-nd whipping of ice cream mix a-nd air to produce ice cream. The ice cream mix is metered into the freezing cylinder by a gear pump. A constant airflow is fed into the cylinder together with the ice cream mix. The freezing cylinder is cooled by the refrigeration plant. During the passage through the cylinder, the air is whipped into the mix by a dasher. The stainless steel blades mounted on the dasher continuously scrape the frozen ice cream from the inside wall of the cylinder. Then the ice cream passes to the outlet pump. There are 150L, 300L, 600L, 1000L, 2000L continue ice cream freezers, a-nd so on.