Operators often use undercounter dishmachines in front-of-the-house bar areas to wash mainly glassware and utensils. These units clean between 24 and 40 racks per hour, with fill-and-drain and heat recovery types on the lower end. Higher-end models can feature adjustable cycle times for light-, medium- and heavy-volume applications.
Undercounter dishmachines come in low-temperature or high-temperature versions. Low-temp machines are not recommended for bars as the chlorine sanitizer can impact the taste of wine and kill a beer’s head. Glassware washed in high-temp units doesn’t leave a residue or scent and is less prone to spotting but requires additional cooling time following cleaning. High-temp units include a separate set of rinse arms and use fresh water heated to at least 180 degrees F for a final sanitizing rinse.
Operators primarily use fill-and-drain units, which have one set of wash arms for heavy soil applications. These warewashers dump excess food waste in the water, which empties completely and then refills with fresh water for rinsing.
Undercounter dishmachines that recirculate water from one cycle to the next also are available. These units reuse the wash water until it becomes soiled and requires draining.
Most undercounter warewashers feature stainless steel construction and measure 2 feet wide by 33 inches tall. Dishmachines with double-wall construction have both an inner wall for the wash chamber and an outer wall for the unit’s outer surface. The benefits of double-wall construction include the outer surface of the machine being kept cooler; less heat loss, which improves energy efficiency; and a lower noise level during operation.
Most undercounter machines operate on a single two-minute cycle. Operators can also choose from among types with longer cycle times that handle heavy soil loads.
To calculate the number of racks per hour that a dishmachine can wash, it would make sense to simply take the cycle time and divide it into 60 minutes. For example, a 2-minute cycle into 60 minutes would be 30 racks per hour. While this appears correct, the appropriate calculation is to use the NSF calculation for racks per hour, which adds 30 seconds per dishrack to account for loading and unloading dishes. This will give the operator a true cycle time. In this case, the actual racks per hour using the NSF calculation is 24 racks per hour, not 30.
Features and Options
Components of these units include removable upper and lower rinse arms, pump drains, detergent pumps, built-in temperature boosters for high-temp warewashers and sanitizing pumps on low-temp machines. Insulated doors, low-chemical alerts and delime alarms typically come standard. Some warewashers have digital controls on top that display water temperature and cycle information, while others can automatically extend the rinse cycle to ensure water reaches 180 degrees F.
A soft-start option minimizes the initial water pressure, protecting delicate items from breakage. Other options include casters for added mobility and 17-inch stands for ergonomic loading and unloading. Because some municipalities require water to be less than 140 degrees when drained, a drain-tempering kit can cool water as it leaves the machine. Power cord kits provide plug-in capability as opposed to hardwiring units. Most machines have self-cleaning modes or timed shut-downs that will automatically drain the unit after several hours if the machine is left on.
Final rinse temperature assurance is an important feature on high-temp machines that rely on hot water (180 degrees F) to sanitize wares. For the water to reach this temperature, the booster heat must be operating correctly. Typically, the incoming water is 110 degrees F. Many dishmachines come with a feature that does not allow the dishmachine to go from the wash cycle to the rinse cycle until the water in the booster heater reaches 180 degrees F.
A pumped final rinse feature will compensate if there’s a water pressure drop or spike, which can impact cleaning results. Some units can adapt to either floor or wall drains. High-end units are available with an active water-filtration feature, which not only requires less detergent but also simplifies cleaning.
Undercounter dishmachines can be purchased with product stands to elevate the units for better ergonomics and provide additional storage space for detergent and rinse aids. These units can also be purchased with casters, which allow operators to pull the units out for easier cleaning.
Energy Star’s most recent guidelines require undercounter warewashers to utilize between 1 and 2 gallons of water per rack, but newer machines use as little as 0.6 gallons per rack. Low-temp units also qualify for Energy Star but use in excess of 1 gallon of water per rack.
New innovations in the category include steam elimination and energy recovery. These two features typically appear together as they are a product of one another. One of the challenges that has always existed with high-temp undercounter dishmachines is that when the rinse cycle ends and it’s time to open the door and remove the wares, the heat inside has produced steam. When the door opens, this cloud of steam comes out into the face of the operator and creates a hot, damp, humid environment for the operator and anyone else in the area. This also restricts where an operator can install the machine because of the steam. This is especially an issue at a bar because the steam would disrupt the environment where customers are present.
Newer low-temp warewashers utilize potable water to rinse off chemical residue after the final rinse and sanitation cycle. This is geared for operations serving wine, beer and specialty cocktails.
Operators should consider the location of the unit. “Will it be under an ADA section of the bar?” asks Emalee Austerman, project coordinator at Camacho Associates, Atlanta. “If so, bar operators will need to make sure it will fit under the counter. Will it be in view of the customer or near customer seating? In this case, they will probably want a low-temp option with a slow start-up to avoid excess steam and noise.”
Operators should also consider the cost of the unit. Will it be leased or purchased? “Leasing the dishwasher is a great option when a customer is looking to save some money,” says Austerman.
Many undercounter dishwashers incorporate a slow start-up feature, similar to glasswashers. “This reduces the risk of breaking expensive glassware from the jolt of the machine starting and also reduces the initial start-up noise,” says Austerman. “Some are also incorporating a drain board option on top of the machine to maximize drying space.”
While the most common application of an undercounter dishwasher is to reduce labor costs by quickly and efficiently cleaning glasses/dishes, it can also in some municipalities take the place of a three-compartment sink in the bar, as long as there is one in a kitchen nearby. “This can free up valuable space at the bar to use for more storage, cocktail stations, etc.,” says Austerman.
When installing an undercounter dishwasher, an aspect that sometimes gets overlooked is allowing space for the cleaning detergent. “There must be space under an adjacent piece of equipment to allow for the chemical storage,” says Austerman.
Cleaning and Maintenance
Regularly wipe down external machine surfaces, floor and wall surfaces.“The more typical style of undercounter dishmachine is very similar to a residential unit,” says Tom McBride, technician for General Parts in Houston. “For a bar footprint where space may be limited for both equipment and personnel, this style presents some challenges.”
This type of dishwasher is accessed from the front by opening the door to a horizontal position, which requires space and blocks passage while opened. “From a maintenance perspective, this style of dishwasher presents some challenges,” says McBride. “The most common maintenance issues are with the water and drain-control valves and cycle timer. The frame sits almost directly on the floor. The working components are located at the bottom of the unit and are difficult to access.” For this reason, the unit may have to be removed from underneath the bar or counter to access the water supply, the drain plumbing and the electrical supply.
Water quality is a contributing factor for both styles of dishmachine and determines chemical quantities and concentration levels. The frequency of cleaning will vary as well.“End-user attention to water leaks, chemical leaks, and poor results, when addressed proactively, will reduce downtime and reduce repair costs and will prolong the life of the dishwasher,” says McBride.