Buying The Right Commercial Dishwasher
e for high volume applications like cafeterias or institutions and can process over 400 racks per hour.
Booster Heaters - these stand-alone units pre-heat
water to the NSF required 180 degrees Fahrenheit for proper
sanitization. They operate independently of the dish machine and insure
that enough hot water is available for washing. Booster heaters are
typically used on large Conveyor or Flight dishwashers that process
large volumes of dishes per hour. Most undercounter and door type units
have a built-in booster heater. Check before you buy any dishwasher to
see if you'll need a booster heater or not.
Choosing the Right Unit
Selecting the right dishwashing unit depends on the amount of
dishes you need to wash in a given hour and the what you are washing.
Some units are specifically designed to only wash glassware or pots and
pans, and if your commercial kitchen has the space, it might be a good
idea to split dishwashing tasks between two specialized units.
You also need to account for volume. Keep in mind that when you
are calculating how many racks of dishes you produce per hour, you
should use the number produced at times of peak demand.
Don't forget about future growth and seasonal trends! A
dishwasher should last at least 5 years, and hopefully in that time
your business will be growing as well, meaning more dishes to wash.
Certain times of year can also be much busier. Make sure the dishwasher
you buy can handle these peak dishload times.
On the other hand, the larger the unit, the more energy and
water it consumes, and if dishes are processed too quickly then racks
tend to go through half empty, resulting in inefficient operation. Make
sure you take the time to accurately calculate dishload and select the
right sized dishwasher. The following chart is a general guideline:
| Meals/hour |
Washer type |
Max racks/hour |
| Up to 100 |
Undercounter |
35 |
| 100-500 |
Door |
125 |
| 500-2000 |
Conveyor |
450 |
| 2000+ |
Flight |
1000 |
Energy Efficiency
As energy and water costs continue to rise, selecting an energy
efficient dishwashing unit has become more and more important to
restaurants and commercial kitchens. Most commercial dishwashers employ
automatic fill and idle pump shutoff features, as well as a built in
booster heating unit to improve energy efficiency.
Energy Star, a government run agency, now rates commercial
dishwashers for their energy efficiency. Energy Star rated units will
operate more efficiently than non-rated ones, so look for the Energy
Star label when you're buying a commercial dishwasher.
High Temp vs. Low Temp
High temperature dishwashers:
- Use heat to sanitize dishes and glassware
- Must achieve 180 degrees Fahrenheit to meet NSF regulations
- Use slightly more energy than a low temp dishwasher
- Do not require the regular purchase of chemicals
- Do not damage flatware and plastics
- Is the most commonly used commercial dishwasher
Low temperature dishwashers:
- Use a chemical bath to sanitize dishes and glassware
- Are not as effective at removing grease
- Are slightly more efficient than high temp models
- Can damage flatware and plastics
- Require you to purchase chemicals on a monthly basis
Some argue that the cost of chemicals for a low temp dishwasher is
much less than the increased energy savings versus a high temp unit.
While this may be true, the main factor to consider when you are trying
to decide between a low or high temp dishwasher is the damage to
flatware, plastics, and dinnerware that might occur with a low temp
model because of the sanitation chemicals used.
Ventilation
The proper ventilation of the dishwashing area in your
commercial kitchen or restaurant is very important, and not just for
the safety and comfort of staff. High humidity reduces the
effectiveness of your dishwasher's drying cycle, and is usually why
dishes come out of a commercial dishwasher damp. Good ventilation for
the dishwashing area in your kitchen is strongly recommended.
Preparing Dishes For Washing
Food bits and other debris should be removed from dishes to
maximize the effectiveness of your dishwasher. The most efficient way
to accomplish this is to use a pre-rinse assembly. Pre-rinse assemblies
are a powerful spray nozzle mounted on a free swinging, upright hose.
Kitchen staff simply depress a lever and wash down dishes before they
go into the dishwasher.
Dishes should also be stacked into a dishrack to maximize their
exposed surface area so they can be cleaned effectively. Most
commercial units are designed to accommodate a standard full size 20" x
20" dishrack. Half racks are also available for smaller units.
Dishwashing racks come in a few standard types:
- Peg racks hold dinnerware, pots, pans, and lids upright for washing
- Flat racks are ideal for washing flatware and have a flat bottom made of tight lattice to prevent pieces from falling through
- Flatware baskets are half rack sized and hold flatware upright for washing
- Glass racks have multiple compartments for glassware and optional extenders that allow you to stack rows on top of each other
Some other useful dishrack accessories include a dolly for convenient
moving of stacked racks and a dishrack hold down grid that fits into a
rack and prevents lightweight items from getting blown out by
dishwasher jets.
Scale Inhibitors
A scale inhibitor is a type of water filter that removes
minerals and sediment from tap water. These elements in the water build
up in the dishwashing unit, increasing the likelihood of maintenance
problems and shortening the unit's life. Unfiltered water also leaves
streaks and spots on glass, dinnerware, and flatware.
Greg McGuire is a regular contributor to The Back Burner, a restaurant news, trends, and marketing blog. He also works for eTundra.com, a company specializing in restaurant equipment, supplies, and equipment parts.