Here are three key signs that your fermented substrate is progressing properly.
✅ Temperature rise.
A healthy fermentation will generate heat. The temperature inside the substrate should rise to 130°F (55°C) or higher.
🔎 If the temperature doesn’t rise:
▪ Make sure the storage box is in a warm room (77°F / 25°C or higher).
▪ Double-check the recipe, something may be missing.
▪ Too much or too little moisture is the most common cause of failure.
High temperatures will speed up the fermentation process.
✅ White Mold (Mycelium)
8 days after fermentation began
15 days after fermentation began
If fermentation is going well, you’ll start to see white mold forming on the surface.
This isn’t a problem, in fact, it’s a good sign. This mold is a type of aerobic bacterium called Mycelium.
It thrives in oxygen-rich environments at around 95°F (35°C), and helps by secreting protein-digesting enzymes that benefit larvae later on. 
✅ pH Level Check.
As fermentation progresses, the pH of the substrate increases. Ideal pH for finished substrate is between 6 to 7.5.
Below 5? That means anaerobic fermentation is taking place, not good.
Above 9? The mix is too alkaline and may be harmful to larvae. Use a simple pH meter or test strips to monitor your substrate as it ferments.
