Theory 084/Food & Agriculture /Post-harvest technology
Post-Harvest Loss Is a Humidity Buffer
Storage advice targets moisture content. The damage may come from fluctuations the store cannot absorb.
Post-harvest loss in stored grain is set by the buffer capacity of the storage environment rather than by the initial moisture content, so grain stored slightly wet in a buffered silo can keep better than drier grain in an unbuffered one.
01The evidence
Storage losses vary widely at similar initial moisture, and the variation tracks the stability of the internal environment.
02The tension
Recommendations specify a moisture threshold for safe storage, which predicts spoilage from the starting condition and ignores the buffering that determines whether it holds.
03The mechanism
Grain spoils when local humidity supports mould growth. That humidity depends on temperature fluctuations and on the store's ability to buffer them, since moisture migrates with temperature gradients.
That makes buffer capacity the determinant, and predicts that a buffered store should outperform a drier unbuffered one.
04What this is not
Threshold advice predicts from the starting moisture. This predicts from the store's buffering, which explains outlier losses.
05Predictions
- P1Loss should correlate with buffer capacity.
- P2Buffered wetter grain should outlast drier unbuffered.
- P3Temperature cycling should drive migration.
06Refutation
Loss tracking initial moisture at controlled buffering would restore the threshold rule.
07What it changes
It would change silo design and storage advice.