Kettles with steam jackets have been available for decades, but the benefits of using pressurized steam remain. Thanks to steam's ability to transfer a large amount of heat energy.
Steam-jacketed kettles utilize pressurized steam in the kettle jacket, from where the steam energy transfers heat via conduction to the food product inside. The steam to the kettle’s jacket can be directly from the steam supply or by a steam generator integrated into the jacket.
Using an integrated steam generator is referred to as indirect heating. Because the initial energy source is not used directly to heat the product inside the kettle but to generate the steam inside the pressurized jacket.
Temperature and heating surface
The temperature of steam inside a pressurized jacket is based on pressure. With higher pressures, a higher temperature can be achieved. Thus, a kettle with a jacket pressure of 1,5 bar produces higher temperatures than one with a 1,0 bar jacket pressure.
Steam jacketed kettles transfer heat energy not only from the bottom of the kettle but also from the sides. This provides uniform heat and dramatically increases the surface area for energy absorption into the product compared to traditional heating only directly from the bottom surface of the kettle.
Reason for steam jacketed kettles
- Faster cooking times because kettle surface comes into contact with the product
- Better food quality due to an even temperature from the entire jacketed surface. The kettle heats its contents from all sides of the unit, providing a gentle, uniform heat that allows consistency.
- Less labor is required as even temperatures remove the constant need to check the product, but provide consistent results day out and day in. Especially in state-of-the-art products that feature temperature control not only for steam but also for the product inside the kettle.
Regardless of these benefits, especially in areas with a gas network, when gas is used, we see kettles using inefficient
direct heating. This might be the result of high technical requirements to integrate a gas-operated steam generator inside a pressurized steam jacket.