1. Start by soaking your oak pellets in water.
One 20lb (9kg) bag of pellets makes about 12 gallons (45L) of substrate.
Put the pellets in a storage box that can hold at least 16 gallons (60L).
Add water gradually, don’t dump it all in at once.
You’ll need about 15–20 quarts (14–19L) of water in total.
Let the pellets fully break down and expand.
2. Add Wheat Bran (10% of pellet weight).
For a full 20lb bag of pellets, use 2lb (900g) of wheat bran.
Avoid adding more than 15% — too much bran can cause poor fermentation.
3. Add Dried Yeast (0.2% of pellet weight).
Use around 0.5–1 oz (15–30g) of dried yeast for a 20lb batch.
This helps kickstart the fermentation process.
4. Add Other Additives (Optional).
Common additives include chitosan and trehalose.
Add these at around 0.1–0.15% of the pellet weight if you choose to use them.
Feel free to experiment based on your own recipes.
5. Mix Everything Thoroughly.
Mix until all ingredients are evenly blended.
🔎 Check the moisture level:
When you squeeze a handful tightly, it should hold its shape without dripping water.
Too much water? It’ll rot instead of fermenting.
Too dry? It won’t ferment properly.
6. Prepare the Containers for Fermentation.
Make holes in the lids for airflow.
Cover the holes with breathable fabric or mesh to keep pests out.
Oxygen is essential for aerobic fermentation.
Without it, anaerobic fermentation takes over, which can ruin the substrate.
7. Stir Every 3–4 Days.
This part’s annoying, but important.
Stirring ensures even oxygen distribution and helps prevent rot.
8. Monitor the Temperature.
Fermentation will heat up the substrate, expect temps to reach 130°F (55°C) or more.
Once it cools back down to room temperature, the fermentation is done.
9. Ready to Use.
A properly fermented substrate will smell earthy, like forest soil or a clean pond.
At this point, it’s ready for your beetle larvae.