Bulk growing

Sterilization vs. Pasteurization

It is crucial to understand the difference:

• Sterilization (15 PSI / 250°F): Kills EVERYTHING. Used for nutrient-rich spawn (grain, flour). If you sterilize bulk substrate, it becomes a "blank slate" for contaminants to take over instantly.
• Pasteurization (140°F - 170°F): Kills bad bacteria/molds but keeps beneficial thermophilic bacteria alive. These good bacteria defend the substrate while your mushroom mycelium colonizes it.

Rule: Always PASTEURIZE bulk substrate (Coir/Verm). Always STERILIZE grain spawn.

Method 1: Bucket Tek (Easiest)

The most popular method for Coir/Vermiculite substrates. It uses thermal mass to hold heat.

You Need:

• 5 Gallon Bucket with Lid
• Boiling Water
• Insulating Blanket/Sleeping Bag

• 1 Prep Ingredients: Put your Coir brick, Vermiculite, and Gypsum into the clean bucket.
• 2 Boil Water: Bring water to a rolling boil. Use our Recipe Calculator for amounts.
• 3 Pour & Seal: Pour the boiling water over the coir. Immediately put the lid on tight.
• 4 Insulate: Wrap the bucket in a thick blanket or sleeping bag. We need it to stay above 140°F for at least 90 minutes.
• 5 Cool: Leave it alone for 6-8 hours (or overnight) until it reaches room temperature.

Method 2: Oven Pasteurization

Good for smaller batches or manure-based substrates.

• 1 Hydrate: Mix your substrate with water to "field capacity" (squeeze test: a few drops come out).
• 2 Load Trays: Put substrate into aluminum turkey roasting trays. Cover tightly with foil.
• 3 Bake: Preheat oven to 170°F (75°C). Place trays in the center.
• 4 Monitor: Use a meat thermometer through the foil. Once the center of the substrate hits 140°F, start a timer for 2 hours.

Comparison

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