Calculate optimal pasteurization times and water volumes for your mushroom substrate. Ensure proper treatment to eliminate competitors while preserving beneficial microbes.
Pasteurization uses heat to reduce competitor organisms in substrate without full sterilization. This selective process eliminates most harmful contaminants while preserving beneficial microbes that can help mushroom mycelium thrive. Unlike sterilization which kills everything, pasteurization creates a selective environment.
The ideal pasteurization range is 160-170°F (71-77°C). This temperature is critical:
Choose the method that works best for your setup:
Most popular. Use cooler or pot. Easy temperature control. 60-90 min.
Uses steam in enclosed space. Efficient for large batches.
pH-based treatment. No heat needed. 12-16 hour soak.
Yes! A cooler works great. Heat water to 170-180°F, pour over substrate in the cooler, close lid, and let sit for 60-90 minutes. The insulation maintains temperature perfectly. This is the most popular home pasteurization method.
Use a thermometer! Substrate must cool to 75°F (24°C) or lower before adding spawn. Spawning into hot substrate will kill your mycelium. Most growers pasteurize in the evening and spawn the next morning after overnight cooling.
No! Pasteurization uses lower temperatures (160-170°F) to reduce contaminants while preserving beneficial microbes. Sterilization uses pressure and 250°F+ temperatures to kill ALL organisms. Most bulk substrates only need pasteurization.
No, never reuse contaminated substrate. It's best to compost it and start fresh. Trying to re-pasteurize contaminated substrate rarely works and risks spreading contamination to your growing area.
Technically no, coco coir is naturally low in nutrients and resistant to contaminants. However, a quick 60-minute pasteurization provides extra insurance and is recommended, especially for beginners.
If temperature drops below 160°F, restart your timer. The substrate needs to maintain 160°F+ for the full duration. Using an insulated cooler helps prevent temperature drops.
Pasteurized substrate should be used within 24-48 hours. After that, beneficial microbes begin to multiply and contamination risk increases. Always spawn substrate when it's at room temperature and freshly prepared.