Description
Pasteurised Bulk Substrate for Mushrooms – Closed-System Boil-in-the-Bag Method.
Our boil-in-the-bag pasteurised bulk substrate is designed for growers who want consistent, contamination-resistant results without the mess, guesswork, or short shelf life of traditional home pasteurisation methods.
Prepared using a sealed, closed-system pasteurisation process, this substrate is hydrated, pasteurised, cooled, and mixed entirely within the grow bag — preventing post-cooling airborne contamination and preserving substrate quality from start to finish.
This method is especially effective for monotub mushroom growing, where substrate depth, moisture balance, and cleanliness directly impact colonisation speed and final yields.
Why Closed-System Pasteurisation Works Better
Unlike bucket, oven, or pot methods that expose substrate to open air after heating, our boil-in-the-bag process keeps everything sealed during the most vulnerable stage — cooling and mixing.
The result:
Lower contamination risk
More consistent field capacity
Longer usable shelf life
Faster, more even colonisation
Nothing is transferred. Nothing is handled in open air. The substrate remains protected until you’re ready to add spawn.
Ideal for Monotub Growing
This substrate is formulated and portioned specifically for bulk monotub applications:
3.5kg bag – ideal for 45L and 80L monotubs when paired with ~1.5kg colonised rye grain
Produces a substrate depth of approximately 3–3.5 inches
Supports full colonisation typically within 7–14 days (conditions dependent)
Also suitable for tray grows and bag-based bulk techniques.
Ready to Use
Each bag arrives:
Fully pasteurised
Correctly hydrated to field capacity
Sealed and clean
Ready to mix directly with colonised grain spawn
No draining, no cooling tubs, no re-mixing in open air. Our prepared substrate is hydrated to correct field capacity so you can skip the guesswork.
Recommended Use & Shelf Life
For best results, use pasteurised substrate as soon as possible after delivery. When stored sealed and cool, it is best used within 10 days to maximise performance and minimise contamination risk.
Key Features at a Glance
Closed-system boil-in-the-bag pasteurisation
Designed for monotub mushroom growing
Reduced contamination risk vs traditional methods
Consistent hydration and texture
Beginner-friendly, repeatable results
- CVG Bulk substrate recipe with added nitrogen
Read why closed system pasteurisation is the best method for bulk substrate preparation at home.
