Worker bees pack pollen into a cell, moisten it with nectar and glandular secretions, and cap it. Lactic-acid bacteria (mainly Lactobacillus/Bifidobacterium) already present grow logistically inside, dropping the pH and pre-digesting the pollen into bee bread — a shelf-stable, more digestible protein store.
dB/dt = r * B * (1 - B/K) (logistic bacterial growth)
r increases with temperature (within range) and humidity
pH(t) drops from ~6.0 toward ~4.0 as lactic acid accumulates
maturity reached when pH stabilizes near its floor
- Temperature — brood-nest temperature; growth rate peaks near the bees' normal ~35 °C.
- Humidity — too dry slows bacterial activity; too wet risks mould instead of fermentation.
- Packing density — how tightly pollen is packed; affects the anaerobic conditions lactic-acid bacteria need.
- Time speed — the real process takes about 1-2 weeks; sped up here to watch it unfold.
This is why bee bread keeps far longer than raw pollen: the drop in pH and bacterial pre-digestion act like a natural pickling process, the same principle behind sauerkraut or kimchi fermentation.