When natural pollen is scarce, beekeepers feed a "pollen patty" — a soft slab of pollen substitute (or real pollen), sugar syrup and sometimes fats/vitamins — laid directly across the top bars of the brood frames. Nurse bees eat the patty and convert its protein into brood food (royal jelly-like glandular secretions) fed to larvae. Too little crude protein and buildup stalls; too much, or fed when bees already have plenty of natural forage, and much of it goes to waste or is simply ignored.
Real pollen patty recipes are usually built around soy flour, brewer's yeast or commercial substitutes because they are shelf-stable and disease-free, unlike trapped natural pollen which can carry spores. Most researchers find diminishing returns above roughly 25–30% crude protein — bees simply cannot process the surplus into brood food any faster.
A 3D hive cutaway shows a pollen patty resting on the top bars of the brood frames, with bees flying between the patty and the comb, shrinking the patty and filling brood cells as they convert protein into larval food.
Brood-cell provisioning speed depends on how closely a patty's crude-protein percentage matches the colony's seasonal demand, how much natural pollen is already coming in, and how strong the colony is.
Set the patty's crude-protein %, dial in natural forage availability, pick a season and colony strength, then watch the protein-match score, patty size, bee traffic and brood-fill percentage respond live.
Most research finds diminishing returns above roughly 25–30% crude protein — bees cannot convert surplus protein into brood food any faster, so matching demand beats maximizing protein content.