PHOTO FROM ENODIS
Chefs of many different cuisines and ethnic styles find that steamer ovens offer them a versatile way to cook because they are highly effective at heating food rapidly without burning or damaging it. Steam also is an excellent way to quickly prepare the fresh fish, vegetables and other items that are components of today's more healthful menu offerings.
Steam's advantages come from its ability to store a tremendous amount of heat energy and then release it all to a food product upon contact (see sidebar). In that sense, it is probably the most efficient heating source. This column will look at some of the most important things to consider when evaluating the most popular types of steam equipment.
Pressure vs pressure-less
In the past, even though pressureless steam convection ovens were available, pressured steamer units were the most popular. Today, just the opposite is true. Pressure steamers are not often used in new restaurant kitchens, though they may be applicable in larger foodservice operations. Chefs have found that convection steamers can do a job comparable to their pressurized counterparts and also offer some additional advantages.
Safety is a prime concern ( pressured steam contains much more energy and can scald much more seriously), so a pressureless steamer is perceived as being less of a potential hazard than its pressured counterpart.
With a pressureless model, cooks can open the cooking compartment at any time to check the product with no wait for depressurization. Most agree that the appearance and texture of green vegetables cooked in a convection steamer is better than product prepared in a pressure model. Convection steamers are also better suited to cooking product directly from a frozen state than pressure models, which perform better with thawed product.
At least a dozen different manufacturers produce steamers. Each has its own selling points and specialized features, and most do an adequate job. There are a wide variety of availablesizes. They range from small two-or three-pan units to large 16-pan multi-compartment models.The smaller three-to five-pan models are usually set on a counter top. The larger models are floor-mounted with stands.
Sizes are rated by their capacity in terms of holding 12" x 20" steamtable pans. It's important to note that ratings are for shallow, 2-1/2" deep pans. Although you may use 4"- or 6"-deep pans, the shallower pans produce a better product and encourage smaller batch cooking for fresher steamed items.
There is an astounding variety of sizes and configurations available in steamers. However, one size is currently getting a lot more attention than others as owners and operators are demanding that high production equipment use less floor area and have a "smaller footprint" to keep construction costs low. At least four manufacturers now have compact countertop units that will sit on a standard 30" deep counter. All are less than 21" wide and some are as narrow as 16". Each holds at least three 12" x 20" x 2.5" deep steamtable pans.
There are three different ways water is heated to make steam for steamers. Most models are available as electric or gas; some can be bought that use direct utility steam connections. These are more common large facilities where steam generators are already onsite for other purposes such as heating. If you do use utility steam, make sure it is clean, meaning that there are no chemicals added that would endanger food.
Electric-or gas-fired steamers work well and produce similar results. To make the electric versus gas decision, evaluate your utility rates. In many areas of the country gas models will be less expensive to operate. Also, consider the initial equipment cost. Typically smaller, electric-heated steamers are a bit lower in cost. As units get larger, first-cost differences tend to disappear.
Manufacturers continue to improve their convection steamers, making them more userfriendly.-Some newer models are also quite efficient and use less water and less energy while delivering the same power as past models. An attractive feature some units offer is automatic water fill and control to eliminate the need to constantly monitor and manually refill the water reservoir. Some steamers also have a standby mode that reduces the water reservoir temperature below the boiling point when not in use, thereby keeping energy usage as low as possible.
Steamers are a flexible and very necessary piece of equipment for most kitchens. However, they do require regular maintenance in order to operate as designed. Any service agent will tell you that steamer issues are the most frequent reason for service calls. Most of these problems are not caused by poor equipment but, rather, a lack of preventive maintenance.
A failure to regularly "delime" a unit to remove sediment created by hard water is the most frequent cause of service problems. If deliming is not performed as required, steamers will not operate at full efficiency and will eventually shut down altogether. It's worth noting that some units have warning lights that tell you when it is necessary to de-lime. This feature can help keep prevent some hefty service bills.
In any case, if you follow a manufacturer's maintenance instructions for your water conditions, your equipment should perform well for many years.
No you're steaming
Because the temperature of steam, when not under pressure, is 212°F, the same temperature as boiling water, it would be easy to assume that the two mediums are comparable in terms of their heating capacity. But nothing could be further from the truth.
The reason is that when water turns into steam, it undergoes a physical transition known as "phase change." The water absorbs a great deal of heat energy as it makes the transition. Later, when steam condenses back into water in a steam oven, it imparts that additional heat energy directly to the food product. In fact, 212°F steam has six times the heat potential of 212°F air. This huge heat transfer potential is why steam is such an ideal cooking medium.
Consider this oversimplified example. You can put your hand in a 400°F oven for a short time and not burn yourself. But if, instead, you put your hand over a boiling teakettle for the same amount of time, the the 212°F steam will scald immediately.
Dan Bendall is a principal of FoodStrategy, a Maryland-based consulting firm specializing in planning foodservice facilities. He is also a member of Foodservice Consultants Society International. He can be reached at 240-314-0660.