Cube ice is a clear, hard ice made by spraying water over a freezing evaporator plate until a sufficient thickness of ice has developed. A defrost cycle then warms the evaporator plate, allowing the cubes to separate from it. Because the entire batch production of cubes releases at one time and falls into either an ice storage bin or an ice dispenser, making cube ice is noisy and less suitable for applications where quiet operation is required.

Each manufacturer of cube ice machines produces distinctive cube shapes and sizes, resulting from differently shaped grids and indentations on the evaporator plate. Depending on the evaporator grid design, the cubes can have a wide range of sizes and shapes. Manufacturers call their cubes by a variety of names - cube, cubelet, diced ice, half dice, pillow cubes, crescent ice, and gourmet ice, to name a few.

How cube ice is made
All ice machines use a process of alternate compression and expansion of a refrigerant fluid to make ice. The major components in a cube ice maker include the compressor, condenser, evaporator and some type of water supply system. A motor within the compressor drives a pump which compresses the refrigerant and in so doing raises its pressure and temperature. The compressed refrigerant gas is then passed through the water- or air-cooled metal coils of the condenser where it gives up its heat to the outside and condenses (becomes a liquid). The liquid refrigerant then flows through an expansion valve where it is allowed to expand into a gas, dropping the temperature of the refrigerant and taking up heat from the water running over the evaporator plate. The vaporized refrigerant is now returned to the compressor where it is compressed and the cycle begins again.

During this cycle, water is pumped over the cold evaporator plate and freezes into the depressions in the evaporator. Water not frozen collects in a sump and is recycled back over the evaporator. When the ice has reached the desired thickness, a defrost cycle loosens the ice from the evaporator plate and allows it to fall into the storage receptacle, usually a bin or dispenser on which the ice machine sits.

Cube ice is clear because the process of running water over an evaporator plate allows dissolved minerals, which could cloud the ice, to fall to the sump before they can freeze into the ice. It is hard because very little air or impurities (which produce softer ice) are trapped in the ice during the freezing cycle. This hardness means that cubes melt more slowly than other types of ice. Cube ice is said to have a high “ice quality”, meaning that a very high percentage of the cube is ice.

Utility consumption to produce cube ice
Ice makers that produce cubes (“cubers”) must reverse the refrigeration cycle that forms the ice and then melt the ice off the plate for each batch of ice made. Because of this, to produce the same amount of ice, cubers use significantly more electricity and water and generate more waste water than nugget and flake ice makers, which do not have a defrost cycle.

When deciding whether a cuber or nugget machine would be best for your operation, be sure to factor in the operating costs. Remember that, in general, cube type ice makers consume about 33% more water and 25% more electricity than a comparably sized flake or nugget machine. Be sure to check the manufacturer's specification sheets for the actual production capacity of the machine, as well as the amount of water and energy consumer top produce the ice.

Cube ice applications:

• Bar use - Cubes are the ice of choice for bar use because their clarity enhances the appearance of alcoholic drinks.
  
• Restaurants and other foodservice operations - Cube ice is also often used for water and beverages in foodservice operations, but nugget and compressed nugget ice makers, with their lower operating costs and chewable ice, will serve equally well. Indeed, the industry has seen a growing preferance for chewable ice for soft drinks.
  
• Convenience stores - Cube ice makers are often top mounted on ice and beverage dispensers in convenience store fountain programs. However, nugget and compressed nugget ice makers, with their lower operating costs and chewable ice, would serve equally well for this application.