Straw Pasteurization for Mushroom Growing

Straw Pasteurization

Pasteurization is a heat-treatment process that destroys pathogenic microorganisms. It is named after the French scientist Louis Pasteur, who demonstrated that fermentation of wine and beer could be prevented by heating the beverages to about 57° C (135° F) for a few minutes.

Different methods for achieving pasteurization

If bulk is your goal, a big metal barrel and an outdoor burner hooked to propane may be the way to go. The “next step down” is the method I demonstrate in the video below. It requires boiling water and a cooler. If you lack a cooler, or just want a small batch of pasteurized straw, you can put some straw in a pillow case and boil it within your biggest pot.

Pasteurization Steps:

  1. Cut straw into smaller strands.
  2. Bring 3-4 pots of water to a boil.
  3. Fill cooler with straw.
  4. Pour boiling water into cooler until straw is mostly submerged. (Leave room to add more water later)
  5. Close cooler to allow stream to build up and to reduce heat loss.
  6. Over the next 90 minutes, check the temperature within the cooler using a thermometer every 30 minutes. The goal is to keep the temperature between 160-190 degrees Fahrenheit (71-87 Celsius) for 90 minutes. Keep a boiling pot on the stove and add if/when needed.
  7. Drain the water, remove the straw and spread across a clean surface to allow it to cool. (Heat hurts mycelium)
  8. The straw is now ready to add to the buckets! 🙂