← Blog
Blog

How to Pasteurize Mushroom Substrate with Steam

August 14, 2026

Pasteurization and sterilization are not the same process for mushroom substrate. The room, load, distribution, temperature measurement, and cooling plan must be designed together.

Substrate bags waiting on racks and bag preparation work in a mushroom production area
Representative process image · Image: USDA/FPAC — Preston Keres · Public Domain · Cropped and resized for the web

First define the target process: pasteurization or sterilization?

These two concepts should not be used interchangeably. The target temperature, duration, pressure, and expected microbiological outcome vary according to the production protocol. Before selecting a generator, the mushroom species, substrate recipe, and process step validated by the facility must be clarified.

The determining factor is not room volume but the total load to be heated

In two rooms of the same size, the number of bags, substrate mass, starting temperature, and rack arrangement may differ. Wall and door insulation, outdoor conditions, cycle frequency, and door opening also change heat losses. Therefore, recommending a model based only on square or cubic meters is not reliable.

Steam distribution and air evacuation

Steam must be able to circulate between the racks and bags, the initial air must be removed in a controlled manner, and the condensate formed must be drained. If the distribution line heats only the area near the inlet, hot and cold zones may form in the room.

According to which temperature should the holding time begin?

The holding time should not be started solely when the generator is activated or based on a single thermometer near the door. Measurement must show that the reference condition defined by the protocol has been reached, particularly in the part of the load that heats most slowly. The number and placement of sensors are determined according to the room-load arrangement.

Cooling and recontamination are also part of the cycle

Uncontrolled air entry, contaminated surfaces, or improper handling after the thermal process is complete may create new risks. Cooling, unloading, and transfer to the next stage should be addressed together with the facility's hygiene plan. The generator alone does not guarantee the microbiological outcome.

Frequently asked questions

How many kg/h of steam is required for mushroom substrate pasteurization?
A reliable flow rate cannot be provided without knowing the total substrate mass, starting and target conditions, duration, room losses, and cycle program.
Is the number of bags sufficient to select a generator?
No. The mass per bag, material, starting temperature, arrangement, room insulation, and target protocol are also required.
Is a single temperature sensor sufficient?
It may be sufficient in a small, validated setup; however, in dense or large loads, temperature distribution may vary, so multiple points should be evaluated.
Can a steam generator be added to an existing room?
Suitability can be assessed after examining the insulation, door, distribution, air evacuation, drainage, sensors, and electrical infrastructure.

Our machines for this job

Alongside standard models, we size the system to your capacity and build it custom. Tested at our facility before shipping, with a 1-year warranty.

Get a quote →

Connection support, first start-up and service

Qualified local tradespeople may complete the connections; we provide remote first-start and fault support when needed. On-site installation is quoted separately.

Service & parts →
Steam is our business!

Let us define the right solution for your steam requirement.

You may need a standard model, a project-specific system, or simply have an idea that is not yet clear. Call us, write on WhatsApp or share your need; we will find the right starting point together.