The “Commercial Titan” of Spawn Production

When efficiency is the priority, this XL Gusseted Spawn Bag is the professional choice. At 20 x 12 x 50cm, this bag is designed to maximize the output of every sterilization cycle. It is engineered specifically for 3kg grain batches, providing the ultimate “Master Bag” for large-scale mushroom farms.

Ideal For:

• Bulk Master Spawn: Produce enough inoculum in one bag to seed 15-20 fruiting blocks.

• Commercial Labs: Perfect for high-efficiency, high-volume grain-to-grain (G2G) transfers.

• Space Optimization: Designed for use in large-format autoclaves and 23L+ pressure sterilizers.

Technical Specifications & Features:

• Maximum Bacterial Defence: The integrated 0.2μm ePTFE filter patch provides the highest level of security against airborne contaminants and bacteria—critical when managing the large surface area of 3kg grain loads.

• High-Volume Capacity: Comfortably holds 3kg of hydrated grain with sufficient headspace remaining for a “break and shake,” ensuring rapid 100% colonization.

• Optimized Sterilization Profile: This bag size is designed to reach core sterility within a standard 2.5-hour (150 min) sterilization window at 15 PSI.

• Industrial 60 Micron Polypropylene: Reinforced thickness to support the significant weight of 3kg of wet grain. The high-quality PP (#5) remains pliable and tear-resistant even after a full 150-minute autoclave run.

• Gusseted Stability: The extra-wide gusset ensures the bag stands firmly upright during filling. This stability is vital when handling the heavier mass of XL substrate loads.

• Hydrophobic Gas Exchange: The filter patch is naturally water-repellent, preventing “filter-lock” (where moisture blocks air passage) during the high-pressure steam cycle.

• Industrial Bottom Seal: Manufactured with a reinforced 4mm wide bottom heat seal. Specifically engineered for high-pressure environments and load-tested to 10kg to prevent blowouts during handling and sterilization.

How to Use Your Gusseted Spawn Bag

A bag is a bag… until you fold it right! To avoid blow-outs, maintain perfect sterility, optimal moisture, and get the best colonization results, check out our detailed step-by-step tutorial:

👉 Sterilizing Commercial Grain Spawn Bags – Full Tutorial

It covers proper folding technique, filter orientation, loading tips, sterilization cycles, and common pitfalls to avoid.

Professional Grower’s Note:

For optimal results with 3kg loads, ensure bags are not “over-packed” in the autoclave. Space between bags is essential for steam to penetrate the centre of the grain mass within the 2.5-hour window.

Take your production to the limit. The STS-approved 20x12x50cm bag offers the maximum scale possible without compromising the integrity of your sterilization cycle.