Here are three key signs that your fermented substrate is progressing properly:
1. 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:
1) Make sure the storage box is in a warm room (75°F / 24°C or higher).
2) Double check the recipe, something may be missing.
3) Too much or too little moisture is the most common cause of failure.
High temperatures will speed up the fermentation process.
2. White Mold (Bacillus)
(Photos 1 is 4 days after fermentation began, and photos 2 is 13 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 bacteria called Bacillus.
It thrives in oxygen-rich environments at around 100°F (38°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 7 to 8.
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.
