A pollen trap is a mesh screen fitted across the hive entrance. Returning foragers carry pollen home packed into two corbiculae (pollen baskets) on their hind legs. To get inside, every bee must squeeze through a grid of holes just slightly narrower than its body — and doing so mechanically knocks a share of each pellet loose. The pellets drop through a screen into a tray below, while the bee carries the rest of its load on into the hive to feed the colony.
Fresh pellets are soft and moist (around 20–30% water) and start fermenting almost immediately, so beekeepers freeze or dry them quickly — traditionally in a fan-ventilated dehydrator at a low temperature — to bring moisture down to a shelf-stable 6–8% without cooking off the heat-sensitive vitamins and enzymes.
A well-run pollen trap rarely exceeds about 50% efficiency by design — beekeepers deliberately leave the majority of returning loads untouched so the colony always has enough fresh pollen on hand to feed developing brood.
Watch foragers squeeze through a hive-entrance pollen trap, shedding a share of their leg-baskets' pollen into a collection tray below — then scrub through drying to see fresh, moist pellets shrink toward shelf-stable storage.
A trap's mesh aperture sets how much pollen is knocked off each returning forager; smaller holes raise efficiency but every design still lets most bees through untouched so brood-rearing pollen keeps flowing.
Tune trap aperture, toggle the trap on or off, adjust forager traffic and season, then drag the drying slider to see moisture fall from a fresh ~22% toward a storable ~7%.
Fresh pollen pellets start fermenting within hours of collection, which is why beekeepers freeze or dry a harvest almost immediately rather than leaving it in the trap tray overnight.