Building Your Own Drum Sterilizer

A DIY Guide for Mushroom Growers

Nick | FSO | 5/29/24

Building Your Own Drum Sterilizer and growing your own mushrooms can be immensely rewarding, but it all starts with a crucial step: sterilization. This eliminates competing microbes and creates the perfect environment for your chosen mushroom species to thrive. While you can purchase a pre-made sterilizer, building your own drum sterilizer is a cost-effective and satisfying option.

Building Your Own Drum Sterilizer: A DIY Guide for Mushroom Growers

Why a Drum Sterilizer?

Drum sterilizers are simple, robust, and reliable. They use steam to effectively kill off harmful bacteria and mold, ensuring a healthy substrate for your mushroom cultivation.

Materials You’ll Need

  • Drum:  A 55-gallon steel drum is ideal, readily available at most hardware stores or online.
  • Next Pressure Gauge, This is crucial for monitoring pressure within the drum during sterilization.
  • Pressure Relief Valve: Ensures safety by releasing pressure if it exceeds a safe limit.
  • Thermometer To monitor the temperature inside the drum during sterilization.
  • PVC Pipe For the steam intake and exhaust lines.
  • Elbows and Fittings To connect the PVC pipe to the drum and your heat source.
  • Heat Source A propane burner or a boiler is recommended.
  • Safety Gear Gloves, safety glasses, and a face mask are essential when working with steam and heat.

Building the Sterilizer

1. Prepare the Drum: Clean the drum thoroughly and remove any rust or debris. Drill holes in the top of the drum for the pressure gauge, pressure relief valve, and the steam intake and exhaust lines.
2. Install the Pressure Gauge and Relief Valve: Securely mount these components to the top of the drum.
3. Connect the PVC Pipes: Run the steam intake line from your heat source to the bottom of the drum. The exhaust line should run from the top of the drum to a safe outlet.
4. Secure the Heat Source: Place your heat source (propane burner or boiler) a safe distance from the drum.
5. Test the System: Before using it for sterilization, run the system with water in the drum to check for leaks and ensure everything is working properly.

Sterilization Process

1. Fill the Drum: Fill the drum with your chosen substrate (e.g., straw, sawdust, coffee grounds) leaving some space for steam circulation.
2. Heat the Water: Heat the water in your heat source to a rolling boil.
3. Start the Sterilization: Turn on the steam intake and allow steam to flow into the drum for 2-4 hours, depending on the substrate and desired level of sterilization.
4. Monitor Temperature and Pressure: Maintain a temperature of 121°C (250°F) and a pressure of 15 psi for optimal sterilization.
5. Release Pressure: Once the sterilization cycle is complete, slowly release the pressure by opening the pressure relief valve.
6. Cool Down: Allow the drum to cool down before opening it and handling the sterilized substrate.
7. Having Clean substrate is great to get started, here is some of our best genetic options. 

Safety Precautions

  1. Never leave the sterilizer unattended during operation.
  2. and always wear safety gear when handling the drum and steam.
  3. Ensure proper ventilation to prevent the buildup of steam.
  4. Be sure to Use caution when opening the drum after sterilization, as it will be hot.

Tips for Success

  1. Use high-quality materials: Invest in a sturdy drum and reliable pressure gauge and relief valve.
  2. In addition under-sterilization can lead to contamination, while over-sterilization can damage your substrate.
  3. Keep the drum clean: Wash and disinfect the drum regularly to prevent the buildup of bacteria.


Ready To DIY

Building your own drum sterilizer is a rewarding experience that empowers you to control the quality of your mushroom growing environment. With careful planning and proper execution, you can create a durable and effective system that will serve you for years to come. Mush love and happy growing!

Spores Mushroom Supplies Liquid Culture


Mush Love To All and thank you for your support and sharing the myco love

Join our newsletter

Sign up to receive email updates on new product announcement, special promotions, sales and more.