If you just bought fermented substrate,
Don’t use it straight out of the bag.
There’s an important step you need to follow first “degassing.”
This means letting harmful gases escape from the substrate before giving it to your larvae.
💬 Why is the substrate releasing gas?
Ever opened a fresh bag of substrate and caught a weird smell?
Sometimes it smells sweet or like fresh forest soil.
But other times, it might smell like ammonia or even poop.
A strong smell usually comes from two things:
• Excessive use of additives
• Lack of ventilation during packaging (especially if it’s sealed in airtight bags,
possible anaerobic fermentation)
💬 Can gas harm my beetles?
Yes, absolutely.
This is one of the most common causes of larval death.
If the substrate is still actively fermenting, it produces heat and gas, both of which can stress or even kill your larvae.
🔎 One sign to watch for:
If the larvae climb up and stay near the surface after a substrate change, gas might be the problem.
✅ How to “degass” your substrate properly
1. Open the substrate bag.
2. Pour the substrate into a large container.
3. Let it breathe for 2–5 days.
Make some holes in the container lid and cover with breathable fabric to keep pests out.
I actually use mushroom bags I sell to speed this up, but I still recommend degassing for 1–2 days before use.
4. Adjust the moisture to around 60%.
Add water little by little, the substrate should hold its shape when squeezed, but not drip.
5. Monitor it for a couple of days.
Make sure fermentation has fully stopped before using it with larvae.
Check for unusual heat or smell.
If everything looks and smells normal, you’re good to go.
