Foragers deliver nectar at ~50-80% water. Invertase (from the bee's hypopharyngeal glands) hydrolyses sucrose into glucose and fructose while house bees fan their wings across open cells to evaporate water down to ~17-18%, the EU/Codex threshold for capping.
sucrose + H2O --invertase--> glucose + fructose
dM/dt = -k(fan) * (M - M_air) , cap when M <= 18%
- Fanning rate — wing-beat airflow across the comb face; scales the evaporation rate constant k.
- Hive humidity — ambient moisture the cell equilibrates toward; higher humidity slows drying.
- Nectar inflow — new droplets deposited per second into open cells, feeding the pipeline.
- Enzyme activity — invertase turnover; shifts droplet colour from pale nectar to amber honey faster.
Capped honey below 18% moisture resists fermentation and meets EU Grade A/Extra criteria; higher final moisture drops the simulated quality grade.