Steamers are most often used to cook items like vegetables, seafood, potatoes and rice since not only is production fast, but items also retain moisture, nutrients and color.
The volume and application will determine what size best suits a foodservice operation. The most common sizes hold three, five or six pans. Countertop and floor-model steamers work well in smaller, lower-volume foodservice facilities. Smaller steamer models will typically accommodate three to five 12-inch-by-20-inch-by-2½-inch steam pans. For larger, high-volume operations, consider a floor-model unit. Most larger units will accept both sizes, generally holding fourteen 12-inch-by-20-inch-by-2½-inch steam pans and seven 18-inch-by-26-inch sheet pans. Some models can be stacked to handle greater capacities.
Generally, foodservice operators serving 0 to 200 meals per hour require a single one-compartment steamer. For 200 to 400 meals per hour, a single two-compartment unit will be necessary. Operations producing 400 to 600 meals per hour will need a three-compartment unit. To prepare 600 to 800 meals per hour, operators need either one four-compartment or two two-compartment units.
The three main steamer types are pressure (boiler-based), pressureless (convection) and connectionless. Pressure types utilize from 5 to 15 pounds of pressure per square inch (PSI) and cook at 228 degrees F to 250 degrees F. Generally speaking, low-pressure steaming units have a lower operating cost and higher productivity than pressureless units when preparing single items. Pressureless steamers cook at 0 PSI and 212 degrees F. Heat transfers via the convection of steam. Unlike pressure cookers, pressureless steamers put steam in direct contact with food products. Another difference is that operators can open pressureless steamers’ doors at any time to check or season food. These units are generally smaller and cook more slowly than pressure steamers.
Operators can use some steamers as holding units, with water boiling at 212 degrees F to hold the cavity temperature at 180 degrees F. Also offering added flexibility, some models accommodate double-stacked pans, which increases production capacity in the same footprint.
Boiled water results in calcium, lime scale and mineral deposits, which are hardened and left behind. For this reason, water filtration is a key component to problem-free steamer operation as well as an extended service life. There are different filter options available, with water quality the determining factor. While some regions have more of an issue with lime scale, others deal with total dissolved solids. Carbon filters take out sediment and chlorine on the steamer’s interior.
Reverse osmosis is a more extensive and pricier water treatment system that strips all minerals and lime out of the water, eliminating the chance of buildup.
One advantage of boilerless units is the cooking cavity is more easily cleaned, whereas boiler units require use of a deliming solution and a more extensive cleaning process.
Many steamer manufacturers offer Energy Star-qualified units. In some cases, this equipment will provide less capacity than other units. These units are said to be up to 50% more energy efficient than standard models and include both electric and gas types.
Steam cookers that earn the Energy Star rating must meet a minimum cooking efficiency of 50% for electric and 38% for gas while also meeting maximum idle energy rates. Idle energy rates are given for three-, four-, five- and six-pan sizes. These steamers also have shorter cooking times, higher production rates and reduced heat loss due to greater insulation and a more efficient steam delivery system. Energy Star-rated steamers also save water compared with traditional units, utilizing 3 gallons per hour versus 40 gallons per hour.
In the past, Energy Star steamers were boilerless and connectionless, but there are now generator-based steamers that are more energy efficient.