Batch freezers perform as the name suggests by creating a large volume of ice cream, frozen yogurt, gelato, sorbet, custard or other frozen dessert in a designated period of time. These units can make anything that can freeze from a liquid to a semisolid state.
Most commercial batch freezers are rated by the barrel size, which is typically in quarts. Sizes range from 3 to 40 quarts, with 4, 10, 12, 15, 20 and 24 quarts the most popular sizes. It’s important to note that the size of the barrel does not necessarily equate to the amount of product the units will produce. This is because the amount of air that goes into a mix, or the overrun, impacts the finished product’s volume. The more butterfat in the concoction, the faster it takes on air. For example, frozen dessert that is 10 percent butterfat or more would only produce half the barrel size since the other half will take on air. If too much of this product is put in the machine, it won’t freeze properly.
The most critical component in this equipment is the beater or dasher, which serves the dual purpose of adding air to the mixture while simultaneously scraping product from the barrel’s sides. The beater resides in the coldest part of the cylinder and rotates between 100 and 120 revolutions per minute. Bars protect operators from the potentially dangerous moving part. The beater creates the proper consistency by pushing product into the barrel center and whipping it at the same time. These blades tend to be plastic and may be replaceable.
Batch freezers also include stainless steel or plastic doors with grills on the front, along with two chutes. Users pour the liquid mixture in the product chute, located at the top of the door. The frozen product exits the unit through the extraction chute. Most machines include alarms or prompts that alert operators when the product is ready.
There are not many options with these machines, although newer combination batch freezers that heat and freeze product are available. With a traditional unit, an operator takes a cold base, like milk, adds flavor and freezes it. In a combo freezer, the base and flavor are combined and heated, which infuses flavor to create a flavor base. The heated product is transferred immediately into another cylinder, which freezes the mixture. Because these units have separate cylinders for heating and freezing the solution, chefs have more control over the variety of products produced. Also, hot milk dissolves powdered mix faster, which accomplishes better fusing and eliminates lumps.
When it comes to ice cream and gelato freezers used for storage and display, there are a number of options. With gelato freezers, the design tends to be more about aesthetics than function.
For ice cream, upright storage freezers are available in a variety of sizes and widths. Most common are one-, two- and three-door units. While some emphasize storage capacity with solid doors, others are designed with glass doors for display and merchandising in the front of house. Dipping cabinets often have glass in front so customers can view ice cream flavors. These are typically horizontal and range from three to eight feet wide. By comparison, storage dipping cabinets are used in the back of house and have flat stainless-steel tops with flip lids.
The ideal ice cream holding temperature is -10 degrees F to prevent separation of the product and butterfat, which can work its way to the surface in warmer temperatures. The cold also freezes out much of the product moisture, which prevents crystallization. Because gelato is a creamier consistency, it is held at about -20 degrees F.
Standard features for these storage freezers include shelves or baskets for holding novelty items and dividers for separating product. Options include door locks and graphics for front-of-house merchandising. Dipping cabinets may offer night covers, frost shields on the interior for better viewing, water wells for rinsing utensils and a choice of casters or legs.
The U.S. Department of Energy recently released new standards for commercial horizontal and vertical refrigeration cabinets, which include ice cream/gelato units. The rules encompass equipment that operates at chilled, frozen, combination or variable temperature modes and that displays or stores merchandise and other perishable materials. The units can have transparent or solid doors, sliding or hinged or a combination. The standards cover equipment designed for pull-down temperature applications or holding temperature applications that are connected to a self-contained or remote condensing unit. This is an update to the department’s 2009 standards and will make the average commercial refrigeration unit about 30 percent more efficient.