Nugget ice, produced in a continuous production cycle, can range in size and consistency from an opaque, semi-hard nugget to a semi-clear, hard, formed shape that rivals the cooling capacity of cubes. In most nugget ice production cycles, water freezes on the inside wall of a cylindrical evaporator. A slowly rotating auger harvests ice from the evaporator wall and moves it to the top of the evaporator where it is then extruded as a nugget form.

Compressed nugget, called Chewblet® ice by one company, goes one step further to compress the exiting ice at the top of the evaporator to remove excess water. This process delivers an ice that has a 90% quality rating - harder and clearer than traditional nugget ice but still not quite as hard as cube ice. Compressed nugget ice has a high cooling capacity and low meltage factor. An additional advantage of compressed nugget ice is that it has a distinctly customer-preferred “chewable” texture. These qualities make compressed nugget ice superior for water and beverage service.

How nugget and compressed nugget ice are made
All ice machines use a process of alternate compression and expansion of a refrigerant fluid to make ice. The major components in a nugget 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 in the evaporator barrel. The vaporized refrigerant is now returned to the compressor where it is compressed and the cycle begins again.

During this cycle, the cold refrigerant chills the evaporator barrel to cause water in the evaporator to freeze to its inside walls. A slowly rotating auger harvests ice from the evaporator wall and moves it to the top of the evaporator where it is then extruded as a nugget form.

Compressed nugget ice machines go one step further and compress the exiting ice at the top of the evaporator assembly to remove excess water. This process delivers an ice that has a 90% quality rating - harder and clearer than nugget but still not quite as hard as cube ice. Compressed nugget ice has a high cooling capacity, a low meltage factor, and superior displacement to cube ice. An additional advantage of compressed nugget ice is that it has a distinctly customer-preferred “chewable” texture. These qualities make compressed nugget ice ideal for water and non-alcoholic beverage service.

Nugget ice will not be quite as clear or hard as cube but compressed nugget ice can come very close to cube ice quality. In addition, because there is no defrost cycle, both nugget and compressed nugget ice makers are quieter and use considerably less electricity and water than cube ice makers to make the same quantity of ice.

Utility consumption to produce nugget and compressed nugget
Unlike cube ice machines that must melt the ice off the evaporator plate for each batch of ice made, nugget machines have no “heating” cycle. Instead, ice is continuously harvested from the evaporator walls by a rotating auger. Because of this, nugget ice makers use significantly less electricity and water than cube ice makers to produce the same amount of ice.

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 ice machines consume about 33% more water and 25% more electricity than a comparably-sized flake or nugget ice maker. 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 consumed to produce the ice.

Nugget and compressed nugget ice applications:

• Hospitals and nursing home facilities - where it is the ice of choice for on-floor patient care. Unlike cube ice, nugget and compressed nugget ice is chewable without chipping or cracking teeth and is less likely to cause choking. Nugget and compressed nugget machines are also valued in hospitals and nursing homes because of their quiet operation. This is because, unlike cubers, they have no sudden release of ice off the evaporator plate. (Anyone who has occupied a hotel room adjacent to the ice machine knows how noisy that batch release of ice can be.)
  
• Rehab facilities - in ice baths and ice bags. Nugget ice conforms well to body contours and does not melt as rapidly as flake ice.
  
• Restaurants - for water and beverage offerings because it rivals the cooling capacity of cube ice, is chewable and costs substantially less to make than cube producing ice makers.
  
• Convenience stores - for fountain programs because it rivals the cooling capacity of cube ice, is chewable and costs substantially less to operate than cube producing ice makers.