Understanding How a Commercial Ice Machine Works
The ice maker is one of the most complex pieces of equipment in your kitchen, and it's the only piece that actually produces an edible product without any active input from staff. That's why it's especially important that it's given the proper attention needed to keep it clean and maintained. Understanding the basics of how a commercial ice machine works will help you clean the equipment and better communicate with service technicians when it's time to tune up or repair the unit. Here's a rundown of the major components and what they do.
Welcome to the Food Zone
The FDA defines ice as a food and expects restaurant operators to treat it as such. That's why manufacturers design the parts that touch ice and the water used to make it with a strong focus on sanitation and cleanability. The area that houses those components is called the food zone, and to improve the sanitation of those pieces, the food zone is separated from the other parts of the machine.
To begin the ice making process in a cube or half-cube machine, water is pumped into the food zone and into the water trough, which acts as a reservoir for the water used in ice production. From there, it flows through a water distributor that cascades the water evenly over the machine's evaporator plate, which is responsible for freezing the water into ice (more on that important component in a moment). Water that doesn't freeze to the plate falls back into the trough to begin the cycle again. Shielding the evaporator to prevent water from splashing onto the rest of the components in the food zone is a large plastic piece called the curtain.
The evaporator plate is where the magic happens inside a commercial ice maker. In cube-style ice machines, it consists of a vertically-mounted metal plate attached to a grid. Refrigerant lines just below the surface of the plate remove heat, lowering its temperature to below freezing. Water flows over the plate in the process described above, and gradually the water will freeze until cubes of ice have formed inside the grid.
When the Food Zone Becomes a Hot Zone
Unfortunately, the wet, dark conditions of an ice machine food zone are ideal for all sorts of potentially harmful life forms to grow and reproduce, including mold, slime, yeast, and bacteria. This is how ice machines have earned a reputation for being one of the filthiest places in the kitchen. Fortunately, the majority of commercial ice machines are designed with easy-to-use cleaning routines that require minimum labor and downtime, and components in the food zone are designed to be easily removed for a good soaking and deep cleaning. Ice machine cleaning involves a few simple steps, which you can read more about in our article on how to clean your ice maker
The second major enemy of an ice machine's well-being is limescale, a naturally occurring residue left behind by hard water. Over time, those minerals can build up on the evaporator plate and other critical ice machine parts and make the machine inefficient or even cause it to break down. Fortunately, manufacturers lay out proper deliming procedures in user manuals. The biggest thing to keep in mind is to only use deliming chemicals that have been approved for use by the manufacturer. Many evaporators are made with nickel coatings to protect them from rust. Unapproved cleaners can strip away that protective layer and expose the underlying steel to corrosion.
As an additional safeguard against ice contamination, many ice machine manufacturers are making food-zone components with molded-in antimicrobial compounds. These compounds don't kill the lifeforms or prevent them from growing outright, but they do create an environment that's not ideal for microscopic organisms to thrive on, so they grow more slowly. An ice machine built with these components can remain more sanitary between cleanings, helping to protect ice from developing an off taste and your patrons from becoming ill.
Harvest Assist Technology
If you've ever struggled to remove ice from an ice cube tray at home, you understand how difficult ice can be to remove from a cold surface. The same challenge is present for removing ice from the evaporator plate. That process occurs in the harvest cycle and is accomplished in one of two ways.
The traditional way of freeing ice cubes from an evaporator plate involves temporarily reversing the refrigeration cycle so that the evaporator plate is heated rather than cooled. Akin to running hot water over the bottom of an ice cube tray to release the cubes, this process loosens the ice stuck to the evaporator so it will fall into the ice bin.
Manufacturers have found a way to speed up the harvest cycle by introducing a mechanical component that pushes the ice away from the evaporator after the plate has become warm enough to release it. This process shortens the ice making cycle, meaning you can produce a higher volume of ice in a given period of time compared to ice makers without the technology. A harvest assist mechanism can also help conserve energy, since running the mechanism that pushes ice off of the evaporator requires less electricity than running the compressor in reverse long enough to melt the ice until it is loose enough to fall from the plate under the force of gravity alone.
Outside of the Food Zone
Other ice machine parts that it pays to understand are the ones responsible for the refrigeration cycle. The most vital of these is the compressor, which is the component that controls the flow of refrigerant through the system so it can remove heat from inside the unit and exhaust it into the air outside the machine. Another important component of the refrigeration system is the condenser. The same way the evaporator removes heat from inside the ice machine to create cold conditions, the condenser dumps that heat outside the machine.
As long as you stick to the ice machine maintenance and cleaning schedule outlined by the manufacturer, the refrigeration components should give you very little trouble. Really, the only component that requires regular attention is the air filter that protects the condenser from collecting dust and debris. That component must be kept clean to ensure that air can flow freely across the condenser to remove heat from the machine's refrigerant. Condensers that aren't shielded by an air filter should be cleaned with a dry soft-bristled brush during your regular ice machine cleaning routine.