As an affordable cleaning option, foodservice operators often use undercounter warewashers as front-of-house glass washers in bars or in high-end coffee shops. Operators can choose between low- and high-temperature units.
The most widely used type, high-temperature machines, include a separate set of rinse arms and use fresh water heated to at least 180 degrees F for a final sanitizing rinse. High-temp undercounter warewashers, which have been used mainly in bars and full-service restaurants in the past, are now experiencing growth in fast-casual, hotel, corporate dining and long-term healthcare segments. Operators often use these machines in conjunction with conveyor warewashers to help supplement the cleaning process.
Because low-temp machines use water at 150 degrees F, they require operators to add chemicals for sanitizing. While it typically costs less to purchase one of these units, they often can cost more to operate because of the additional chemicals they require to complete the sanitizing process.
Low-temp machines are not recommended for bars, as the chlorine sanitizer can impact the taste of wine and kill a head of beer. By the same token, glassware washed in high-temp units don’t leave a residue or scent and are less prone to spotting but require additional cooling time following cleaning.
Operators primarily use fill-and-drain units, which feature one set of wash arms, for heavily soiled applications. These warewashers dump excess food waste in the water, which the units completely empty and refill with fresh water for rinsing. As a result of this process, these units often use more water. Operators can choose between high- and low-temp fill and drain units.
Most undercounter warewashers are constructed of stainless steel and are 24 inches wide and 33 inches tall. Glasswashers also are available that can be placed either under or on top of counters. These typically measure 16 inches by 16 inches to fit coffee mugs. Double wall construction is available on some units, which provides quieter operation for front of house use and a cooler exterior.
Undercounter warewashers clean between 24 and 40 racks per hour, with fill and drain and heat recovery types operating on the lower end of that spectrum. Higher end models feature adjustable cycle times for light-, medium- and heavy-volume applications.
The 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. Standard features generally include insulated doors, low chemical alerts and delime alarms.
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 F when draining, a drain tempering kit can help cool water as it leaves the machine.
Energy Star standards have pushed manufacturers to produce more efficient machines. The most recent Energy Star guidelines require undercounter warewashers to utilize between 1 and 2 gallons per rack, but newer machines use as little as 0.6 gallons per rack. Low-temp units also qualify for Energy Star ratings, but may use more than 1 gallon of water per rack. Energy Star-rated warewashers also reduce the consumption of detergent and rinse aids.