Convection steam ovens

Convection steam ovens.

Combi-steam ovens are today a determinant of modern restaurant kitchen and guarantee it, that the prepared dishes will meet the highest standards, both in terms of taste and health. Replacing traditional heat treatment devices with one combi steamer makes it possible to prepare several dishes at the same time.

The first convection oven- steam went to the restaurant kitchen over 30 years ago. This invention is the result of work on the intensification of heat treatment of dishes. You need to know, that too long processing adversely affects the content of nutrients in the dish. Therefore, it was necessary to improve the heat transfer coefficient and eliminate the cold layer of air in the devices.
Today, few people can imagine working in a restaurant kitchen without a combi steamer. How this device works? Its power lies in forced air circulation, which increases the heat transfer coefficient several times while reducing the wall's cold zone of the product and its thermal resistance. The additional use of steam increases the heat transfer coefficient 30-60%, the heating medium is a steam-air mixture instead of dry air. Water vapor in the first stage of the process comes into contact with cold products and condenses, thanks to which it gives off its heat to evaporation and at the same time moisturizes the product. Thanks to this, weight losses are small, and almost all valuable substances, such as mineral salts and vitamins remain in the food.

Types of combi steamers.
Convection steam ovens are divided into spray and boiler furnaces; depending on this, where the steam is formed. In the case of the first type of devices, steam is produced in the cooking chamber - this is possible thanks to the introduction of water inside the fan. The humidity is regulated by an electromagnetic valve and a reduction fan. Depending on this, as the humidity is programmed, the spray volume changes to the center of the fan. In boiler devices, the steam generator is connected with a steam condenser and a device that automatically cleans condensate in a closed system.
Three types of heat treatment are possible in condensing steam furnaces.
The first - with hot air, which circulates evenly in the furnace chamber at temperatures between 30-280 ° C, the second - with the use of steam, the so-called. combined system, in the temperature range from 50-280 ° C, optimal for all types of meat and the third - in steaming under atmospheric pressure, i.e. steaming, at temperatures of 30-130 ° C, With this difference, that the steam is not pressurized (as with traditional cooking) and thanks to this, micronutrients are not rinsed out of the food. So you can bake in them, to fry, simmer, dry, to cook, grill and keep at the right temperature and regenerate various types of food. Thanks to this multifunctionality, the stoves are able to replace various types of other kitchen appliances.
Combi-steam ovens are also equipped with a baking function based on a constant temperature difference between the chamber and the core of the food. (delta T). In the first phase of the process, the meat is processed low, with time increasing temperature. In the second phase, it turns brown at an increased temperature. The inverse of delta T is the Roast + Hold program, in which the meat is browned first, and then baked at a reduced temperature.
To optimize the weight loss of products, ovens are equipped with one or more multi-point core probes, thanks to them, an integral temperature measurement is possible, especially helpful when preparing several different dishes at the same time.
With the development of electronics, it became possible to combine combi steamers in sets with other devices. For example, Stalgast offers an innovative line of UNOX combi steamers ChefTop. The modular structure of the devices enables the implementation of basic tasks in the kitchen: Cook and serve - the combination of two ChefTop ovens allows you to simultaneously prepare dishes requiring different environments just before serving them. Cook and serve - combining the ChefTop with a heating cabinet allows you to store previously prepared dishes until serving. Cook and chill, Cook and freeze - a combination of an oven with a blast chiller-freezer allows you to cool or freeze previously prepared dishes. Before serving, the dishes are regenerated in the oven. Each set is controlled by one panel. It is possible to control up to nine other devices from one panel.

Program i security.
Programming the furnace is of great help there, where various dishes are cooked from the regular menu. After programming, it is enough to put the gastro container with the prepared product into the oven and select the appropriate program. A temperature probe has also become a standard furnace equipment, which shows the current temperature in the center of the food - when the set temperature is reached, the oven will automatically end the cooking process. The probe data is important in tracking HACCP points.
The software makes your work a lot easier, also for less experienced chefs. One button is all it takes, and with the same preconditions, we will always get the same cooking result. Easy and quick search for a program with the possibility of reprogramming and up 200 built-in programs with five sub-programs and the ability to close individual programs, will ensure any cook has lasting results in food preparation. The quick cooling function is very important, which allows the temperature inside the cooking chamber to be lowered between individual food preparation processes.
To keep the stoves clean, more and more companies equip their devices with an integral automatic washing system. This saves time both for cleaning the device and time, which would have to be spent waiting for the device to cool down to a temperature suitable for hand washing, while always ensuring hygienic cleanliness of the cooking chamber.
Uniform air circulation in the furnace chamber is regulated by installing one, or several fans on one of the walls of the cooking chamber. They can be placed on the side or back wall of the chamber. This is correlated with the arrangement of the containers inside the oven. The advantage of this solution is the possibility of using containers smaller than 1/1 GN without the need for additional furnace equipment. When the fans are located on the side, GN containers are usually placed with the wider side in the furnace. One disadvantage is the need to install an additional rail in the case of using containers smaller than 1/1 GN.
To best adapt the device to a specific kitchen, more and more companies offer their customers stoves with the option of opening to the left side. This solution enables greater freedom in setting up such a furnace. Most manufacturers supply stoves with double or even triple glazing, to avoid possible burns. The Dora Metal company offers double glazing with a ventilated outer pane and a two-stage door lock opening system, protection against burns, especially during the operation of the furnaces.
When choosing a device and equipment, you should take into account the possibility of its use in your business. Therefore, you should first evaluate the number of meals served daily and the type of these meals. The more options the oven has used in a restaurant that works à la carte and organizes banquets, the faster the investment will pay off. z

The most common errors in the use of the stove are:
• improper use of the probe,
• improper hygiene of the seals,
• use of unsuitable cleaning agents,
• not descaling the device,
• too intensive exploitation, not adapted to the size and processing of the kitchen.

Service immediately.
Continuous operation of the furnace, usually all the time, leads to minor or more complicated faults. So professional servicing is absolutely essential. Each manufacturer or distributor has a different way of solving servicing problems.
Small things break most often: bulbs, seals, but if they are not replaced on an ongoing basis, their lack becomes a problem destabilizing the work of the kitchen. Companies usually do not employ an army of specialists ready to call the client. Anyway, it would be unnecessary - since combi steamers are bought by restaurants all over the country. And that is why websites usually employ several people. Their tasks include, first of all, getting acquainted with the problem as quickly as possible - usually by phone or via e-mail - and making the correct diagnosis. Before any fault occurs, it is up to the service technician, whether the equipment starts working at all. Although combi steamers are relatively small, their placement is of strategic importance. First of all, before starting the installation, the service technician should check the water hardness and its pH in the restaurant. In the case of hard water, you must be prepared for its descaling and appropriate softening devices.
According to the manufacturers of parts, the faults could be avoided. Most follow, unfortunately, from bad use, the contamination of ovens, no descaling, attempts to modify electrical installations, switching devices without authorization, which can lead to this, that the stove will not be level. Unauthorized relocation of the furnaces near the gas burners is unacceptable. Can cause, that, for example, knots with water will be bent.

The benefits of the stove:
• possibility of fat-free processing - dietary dishes
• steaming - no loss of mineral salts, preserving the color of vegetables
• possibility of cooking different dishes at the same time without the smell passing through
• minimized weight losses
• energy and water savings
• saving working time, less staff
• the ability to save the processing of your favorite dishes
• control of machining parameters
• measuring the temperature of the food during cooking