Behemoth 55 gallon barrel sterilizer

$5,000.00 $7,500.00


The Behemoth barrel sterilizer is borne out of the innate need for mushroom growers to spend less on labor, accelerate time to market and increase efficiency across the entire grow.

We've all had the struggle of running walls of pressure cookers, limited loads, sketchy back-room DIY builds, or pasteurization rigs operating at atmospheric pressure requiring 24-36 hour cook times to hit the sterile safety point.

Behemoth is born out of a year of testing, design and failure. At the Humble Fungus we run our barrel 24 hours a day, 7 days a week and it saves us an immense amount in time and effort.

Also, physics and the laws of thermodynamics are sweet.

Pre-order information:

  • The design is not final and small changes to parts or the design/build may occur, like pretty insulation!
  • Please allow 6-8 weeks for assembly and delivery - we are still working on bulk suppliers for all parts, and parts have lead time too.

WARNINGThis is not a certified pressure-holding vessel, we can not recommend that customers run this at pressure. The Humble Fungus can not be held liable for customer usage and by purchasing this sterilizer you agree to indemnification from all liability, injury or loss of product.


  • Capable of running at 10PSI pressure (240F/115C) with a self-installable 10PSI auto-bleed valve
  • Capable of holding 250lbs of substrate per run (50, 5lbs blocks)
  • Pre-assembled and portable PID controller with 3 prong connector, capable of 11000f 
  • 120v power connector, only requiring a dedicated 20 amp circuit
  • 15 PSI liquid-filled pressure gauge
  • 3/4" hose adapted with pressure gauge / flow valve
  • 3/4" quick-connect hose adapter
  • 1.5"-2" high temp PID probe with 6 foot cable
  • Insulated outer body helps with ramp-time and heat loss
  • Reinforced locking steel lid with gasket
  • 1.2 mm stainless steel barrel and lid rated for hazardous waste disposal
  • Wheels! It has wheels.
  • Interior false bottom 
  • Stainless steel float valve

Usage Notes:

  • Cook times: 10PSI is 240F / 115C, 15PSI is 250f / 121C - this means your cook time is longer to hit the same sterilization point, but not that much longer (add 20-25%).
    • For example, if your cook is 2.5 hours @ 15PSI, at 10 PSI, you would add 20-25% to the time resulting in a 3.5 hour cook, not including ramp up and cool-off.
  • All hoses and cables have quick-connects, allowing you to roll the barrel in and out-of sterile environments to load & unload.
  • All parts are customer-serviceable and replaceable.
  • Yes, you can sterilize grain, see cook-time extension above ... but....
  • ... if you built a custom rack to prevent direct stacking you could do no soak no simmer no seal grain cooks. 


  • As we can not recommend running this at pressure, the bleeder valve is not installed, leaving it in atmospheric pressure mode. Parts and instructions for installation are included.
  • All you do is unpack, connect to power and water and substrate and load the machine 

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