Steamers are used to cook vegetables, seafood, and other foods where moisture retention is essential to appearance and taste.
Steam cooks food much faster than hot air, improving productivity. Steaming also reduces shrinkage, increasing profits. Steam equipment is relatively easy to use, even for inexperienced operators. Many models include programmable controls that remove guesswork from the cooking process.
Steam also preserves the nutritional value of most food. This is becoming more important to today's health-conscious consumers.
A combination oven/steamer combines the dry heat of a convection oven with the moist heat of a steamer, and chefs can choose among three different cooking modes. This ability makes this piece of equipment extremely flexible and productive.
Four major types of steamers are available: Pressureless Steamers, Convection Steamers, Pressure Steamers, and Combination Oven/Steamers.
A pressureless steamer uses steam at normal atmospheric pressure to cook food at a constant temperature, which is about 212°F near sea level. However, this temperature drops as altitude increases, so pressureless steamers operating at high altitudes have longer cooking times due to lower steam temperature.
A boiler injects steam through the cooking compartment's sides where the steam contacts the food, releasing heat energy as it condenses. A pressureless steamer can cook a variety of foods at the same time with no transfer of flavor between foods. A chef can open the door at any time to stir food or check on cooking progress.
Pressureless steamers are usually equipped with programmable controls. They are available in countertop or floor units, and some models are also stackable to reduce floor space use.
A convection steamer operates much like a conventional pressureless steamer. However, it provides slightly more uniform temperature distribution by using a fan to circulate the steam and air mixture (similar to the way convection ovens circulate hot air). The convective flow of steam accelerates heat transfer to the food.
Like a conventional pressureless steamer, a convection steamer can cook multiple foods at once with no flavor transfer between foods.
A c steamer uses steam supplied under pressure at 5 to 15 pounds psi (per square inch). It is very similar to old pressure cookers, which had the advantage of cooking meats and stews more quickly, and which also tenderized tough grades of meat. Pressure steamers have always been popular in large kitchens, schools and institutions.
Pressure steamers have a locking door that seals in the steam and holds the higher pressure and higher condensing temperature in the cooking compartment. Because of this, the main disadvantage of a pressure steamer is that a chef can't easily access its contents. The unit must be depressurized before opening, and when it is closed again the unit takes awhile to regain operating pressure.
Combination oven/steamers merge the advantages of a steamer's moist cooking with those of a conventional oven's dry air cooking. These units are often praised for their versatility, because chefs can use the oven mode for baking and roasting during peak traffic times, or they can use the steam mode when extra capacity is needed. However, the unit's ability to cook in the combination mode is its most important quality.
Combination mode is controlled by a microprocessor, which alternates the unit between steam mode and oven mode. For example, under steam mode, roast beef cooks in about half the time of oven mode, but customers like to see meat "browned." Therefore, the combination unit cooks under steam until the meat is mostly cooked, then automatically switches to oven mode to finish cooking and produce the desired browning effect.
New steamer technologies
Steam equipment incorporates relatively simple technology. Most of the improvements come from microprocessor controls. These controls remove much of the guesswork from steamer use through pre-programmed cooking times for specific food products.
Other models called vacuum units are available that operate at reduced steam pressures. These can cook foods at temperatures below 212°F. Some models are even boiler-less units.
In addition, manufacturers are always looking for ways to achieve greater energy efficiency out of the gas-fueled boiler. Electric boilers are already highly energy efficient.
Comparing electric vs. gas steamers
There are many factors to consider when selecting a steamer: initial cost, food preparation productivity, ease of operation, heat generation in the kitchen, and whether electricity or gas is used as the energy source. However, consider that energy only accounts for 3 to 5 percent of a typical food service establishment's total costs. Therefore, while one fuel may be less expensive in a BTU to BTU comparison, the best choice in cooking equipment is the one that minimizes total operating costs, not just energy costs. Features that reduce labor costs or result in higher food product yield will nearly always outweigh any energy considerations. Make sure that you include all of these factors in any equipment evaluation.
Therefore, when comparing gas and electric models, compare equipment that is similar in all ways except the energy source.
Advantages of electric steamers
In general, electric steamers offer these advantages:
- Electric units are more efficient, adding less heat to the kitchen which ultimately must be removed by the cooling system.
- Electric units require less maintenance and ventilation, and are more portable.
- Energy and Money Saving Tips
Here are a few common-sense operating tips that save money:
- Steamers preheat relatively quickly because of steam's high heat transfer. The units are usually well insulated to reduce heat loss to the kitchen and to require less energy to maintain temperature during slow times. However, if using multiple steamers during peak times, turn one unit off after the peak cooking cycle.
- Try to keep each steamer unit fully loaded when possible. The steamer operates at peak efficiency and productivity at full load.
- One key to efficient steamer operation is controlling water quality. If water in your area is "hard" or contains significant levels of chemicals, the compounds in the water can coat and corrode the steaming components. Such scale and chemical carryover can deteriorate steamer performance and food quality, and almost always results in premature steamer component failures. Always check with a professional water treatment company about proper water softening for your steamers.
- Keep each steamer unit properly maintained; a clean and well maintained unit operates more efficiently and reduces repair costs. Check that the door seals properly so steam doesn't escape into the kitchen. Also ensure that the boiler is clean, burners or heating elements function properly, and steam injectors are free of debris.
All steamers have a cooking compartment that looks much like the inside of an oven. Some units have more than one compartment. Each compartment typically holds about 3 full size steam pans, but sizes vary by manufacturer. The cooking compartment is usually made of stainless steel to make it easy to clean and resistant to corrosion. A drain in the bottom of the cooking compartment drains off any excess water that condenses inside the unit.
Pressureless steamers have a door that simply latches in place, and the units may be opened and closed during the cooking cycle. Pressure steamers are equipped with a door that locks tightly to hold pressure and prevent steam leakage. These units generally should not be opened during cooking, since they will emit a burst of steam through the opened door, much like the first burst of steam from a boiling pot of water. Obviously, this is hazardous to kitchen workers.
Steam can be provided from a boiler built into the unit or from an outside source. Built-in boilers use gas or electric energy to heat water, similar to any other boiler unit. Steam flows into the cooking compartment through small holes or jets that are usually located on one side of the cooking compartment.
Many units also use a set of condenser coils located opposite the steam jets to capture excess steam. They condense the steam back into liquid water and drain it out the bottom of the unit. This prevents tastes from transferring between foods.
The convection steamer has a fan inside the cooking compartment which circulates the steam/air mixture, increasing air movement and heat transfer to the food. The convection steamer therefore cooks food slightly faster than a conventional unit.
Steamer operation tips and issues
Steamers look and operate much like ovens. An electric or gas boiler creates the steam, which is injected into the cooking compartment. Steam is a much quicker heat transfer medium than hot air. For example, a full size turkey that takes hours to cook in a conventional hot air oven will cook in minutes in a steamer.
Steam energy is transferred to the food at lower temperatures than hot-air cooking, reducing the chance of overcooking foods. For example, steamers operate at temperatures of 212° to 240°F, while a typical hot-air oven operates between 350° and 450°F.
However, cooking at this lower temperature does not brown food as well as a hot-air oven. For this reason, chefs often use a steamer to cook food almost to completion, and then transfer the food to a conventional oven for a short period of time for surface browning. They can also accomplish this using a combination oven/steamer, which is designed to do both steam and hot-air cooking.
Steamer cooking performance depends on food product cooking time and the output capacity of the steam generator. Cooking food for the proper amount of time within the capabilities of the steam generator results in consistent quality, portion after portion.
Many new steamers have programmable controls to maintain consistent cooking time and steam volume inside the unit. Food service operators simply set the amount of time a dish must cook. The programmable controls also permit a chef to pre-program cooking times so less experienced employees can simply choose the food item from a menu on the control panel.