Ice making equipment is practically a universal need in today’s foodservice kitchen. Every operation, no matter what the menu, serves beverages and requires ice. This month we will examine the types and capacities of ice makers on the market and give some recommended sizing guidelines. We will also look at some of the available features to consider when you are making an ice maker decision.
There are two types of ice made by two different types of machine processes. Each type—cube ice and flaked ice—has a specific application in foodservice. The classic ice type for beverage service is cube ice. Commercial quality cube ice differs from that made in ice trays in how it is produced.
Commercial cube ice can be made in one of two ways. One is by freezing running water over a chilled plate. Ice forms into a slab to be cut into cubes by grids of heated wires when it reaches the proper thickness.
A second method is becoming increasingly common. Streams of water are injected through nozzles into small, chilled cube-size cups until the ice reaches the desired size and is released to a bin below. The cube-sized cups are grouped in large trays usually mounted upside down or vertically, so water runs through and can be recirculated until frozen. The seemingly wasteful process of dumping or recirculating excess water is actually producing that appealing crystal-clear cube we like in a beverage. While pure water is freezing in these cups, many of the impurities frozen in our home ice, which make ice appear cloudy, are not freezing.
Flake ice is the second ice type. A flaker ice maker also has a freezing plate, typically a cylinder, with a device that scrapes ice from the plate as it is formed. Before the ice is deposited into the storage bin, excess water is squeezed from the ice. Hard, dry flakes are produced, which are ideal for rapid product cooling—as in icing down poultry or seafood. Flaked ice also is attractive for buffets, salad bars, or dining room food displays. Remember to provide adequate cooling to required temperatures. Maintaining the required temperatures often means supplementing ice with a refrigerated pan or display area.
Flaked ice can also be used in beverages, but most consumers tend to prefer cubes. The cube tends to melt more slowly than flaked ice because it has less surface area and water is not trapped inside the cube, as there is with flake ice. The slower melting of an ice cube results in an in-tact beverage and tends to fill a glass better—both of which are especially important in a bar.
Once the type of ice—cube or flake—is decided, machine size needs to be selected. Both cubers and flakers are available in a wide range of sizes and styles to match your specific operating needs. Ice makers are typically rated by production in pounds per 24-hour day. Cubers and flakers both range from less-than 100-pound capacities to more-than 1,000-pound capacities. Note that some manufacturers’ ice-making claims are based on a 50°F water temperature and 70°F air temperature in the vicinity of the ice maker. These temperatures are unrealistic because kitchens are usually hotter than 70°F, causing the machine’s capacity to decrease.
A number of manufacturers are now adopting the standards set by the Air-conditioning and Refrigeration Institute which prescribes more realistic operating conditions. The Institute compares machine production capacities at 90°F air temperature and 70°F water temperature, more like the kitchens we all know. When sizing your ice maker, be sure to take into account the air and water temperature to be certain enough ice can be produced. As a rule of thumb, a 10°F air temperature increase may reduce daily ice production by 10% when using an air-cooled machine. In addition the higher room temperature will melt ice in the bin quicker, requiring more ice making capacity to replenish and fill the bin. Using water-cooled ice makers, especially for larger machines, can reduce the amount of heat the ice maker itself adds to the kitchen. The amount of heat generated by air-cooled machines is significant, especially if located in a small, confined area or a space you may be trying to air-condition for the comfort of kitchen staff.
All ice makers employ either air or water to cool their refrigeration compressor/condenser systems. Each has advantages. The air-cooled condenser is cost-effective and involves no added water costs. In some areas, a water-cooled machine must be on closed loop systems, meaning no water can be dumped down a drain. A closed loop and cooling tower may or may not be feasible in your building. The water-cooled system does have some significant advantages in machine efficiency if water cooling is practical in the operation. Water-cooled units are also desirable in kitchen areas where there are high levels of grease or other contaminants. A variation of the air-cooled system, the remote condenser, offers some advantages of its own. The remote unit takes the heat-producing component, the condenser, out of the ice maker altogether. The remote approach does not require water and removes the heat from the kitchen. The compressor/condenser can be located up to 100 feet away outdoors or on the roof providing some advantages but at an added cost.
Some manufacturers make stackable ice cubers. The stacking feature is a good consideration if you expect business to grow over several years, and if you think you may want to increase ice production while using the same floor space. Another benefit with stacked cubers is that if one maker is out of order, the others will produce ice.
Equipment capacity sizing is an important factor in purchasing an ice maker. Ice machines are expensive, costing anywhere from $5 to $12 per daily pound of production capacity (total machine cost—24 hour ice-making production in pounds) in just the initial maker cost not including a bin or operating cost. Since ice cost can often approach the cost of the beverage being served, you should size the maker and bin carefully.
The classic method used by many foodservice operators and equipment dealers alike for sizing ice makers is to put in the largest machine that can fit in the available space. Their concern for having a machine with enough capacity is often well-founded, but money and space can be saved by using a quick sizing analysis formula. Your goal to have enough ice to fill peak demand can be met while not wasting equipment expense and energy usage by selecting oversized equipment.
To size the ice maker, you need to project your highest ice demand week of the year and apply the following formula:
Weekly volume ÷ seven days X 1.2 = Average daily ice usage
The 1.2 multiplier is a safety factor to allow for decreased capacity or increased ice demand.
Another sizing determination which is just as important as ice maker sizing is the sizing of the ice bin. Since most operations have peak days and lean days each week, bin sizing is crucial to be able to accommodate the peaks. It is also always more cost effective to store ice than to provide extra production capacity. It is two to three times more expensive to produce a pound of ice than it is to store it. Keeping costs in mind can maximize equipment efficiency and minimize capital expense.
For example, assume by using the above formula you calculated the average daily ice usage to be 300 pounds per day. If your ice usage was, in fact, a constant 300 pounds per each day, a 300-pound bin would suffice. However, that is not often the case. Let’s say in this example that Sunday through Thursday, your operation uses 250 pounds of ice, but on Friday and Saturday (your busiest days), 425 pounds of ice are used. If you were to use a 300-pound bin in this situation, you would be out of ice on your busiest days.
The best way to size the ice bin in the above example is to take the amount of ice usage above the determined ice maker capacity (300 pounds) and total the amounts. In our example, Friday and Saturday are both 125 pounds above capacity (425 pounds - 300 pounds = 125 pounds) for a total of 250 pounds over. Add the average to the daily capacity to determine bin size. If we size the bin for 550 pounds (300-pound ice maker size + 250 pounds peak usage = 550 pounds necessary bin size), we can go through the entire week with just the right amount of ice to take us through the peaks without over- or undersizing-equipment.
The above example gives us a relatively larger bin which is not needed five out of seven days of the week. But since the cost of making ice is several times the cost of storing ice, pound for pound, it is always a better buy to build in more storage capacity than ice maker capacity. Since your goal is happy patrons, provide them with the ice they will demand during the summer months and year-round. A properly-sized ice maker will also be one less headache for you, the operator.