# Indirect Heating in Food Production

Source: [https://www.stilsan.com/en/solutions/pisirmede-buhar](https://www.stilsan.com/en/solutions/pisirmede-buhar)

Process solutions in which steam provides more balanced heat transfer through the surface in jacketed kettles and similar equipment without coming into contact with the product.

## Operational need

In dairy products, sauces, syrups, and similar fluids, direct flame or intense localized heat can increase the risk of scorching, color changes, and recipe deviations. The product's viscosity, mixing arrangement, and batch duration affect the selection of the heating method.

## How does the solution work?

Steam circulates in the section of the jacketed kettle that does not come into contact with the product and transfers heat through the metal surface. When used together with an agitator and appropriate control, it helps provide more balanced heat transfer. Condensate is removed regularly; process pressure is kept within the permitted values of the equipment.

- Closed-loop approach in which steam does not come into direct contact with the product
- Controlled pressure and temperature management
- Condensate drainage and recovery when required

## Information that determines the correct capacity

The batch volume and mass, initial and target temperature, required heating time, physical properties of the product, kettle jacket area, and number of simultaneously operating equipment units are required. Generator capacity is determined based on this heat load and plant losses.

## Installation and service

The pressure permitted by the kettle manufacturer, safety equipment, steam inlet, and condensate outlets are verified. The selection of piping, valves, and steam traps is made according to the project. During commissioning, the control sequence and operator steps are tested; the maintenance plan is established according to water quality and the operating schedule.

## Field application videos

- [Gıda üretiminde buharla dolaylı ısıtma](https://www.youtube.com/watch?v=4WgHextWxw4)
- [Ceketli kazanda buhar uygulaması](https://www.youtube.com/watch?v=k1Gt9aFSnxc)

## Frequently asked questions

**Does steam mix with the product during indirect heating?**

In sound and properly designed jacketed equipment, steam does not come into contact with the product; heat is transferred through the metal surface.

**Can scorching be completely prevented?**

Indirect and controlled heating can reduce the risk. The result depends on the product recipe, mixing, surface temperature, cleaning, and operation.

**Why must condensate be drained?**

Condensate accumulated in the jacket can make heat transfer irregular. A suitable steam trap and pipe slope support operational stability.

**Can it be connected to an existing jacketed kettle?**

It is technically evaluated after the kettle pressure class, connections, and safety equipment have been verified.

## Related products

- [ST-1 Steam Generator](https://www.stilsan.com/en/products/st-1-buhar-jeneratoru): ST-1
- [ST-2 Steam Generator](https://www.stilsan.com/en/products/st-2-buhar-jeneratoru): ST-2

## Related technical guide

[The Advantages of Steam (Indirect) Cooking in Food Production](https://www.stilsan.com/en/blog/gidada-buharla-pisirme)