Pollen is a source of protein, vitamins, mineral and some carbohydrates for honeybees. One pollen alone does not provide a bee with all the nutrients they need to stay healthy, so a variety of pollens are needed to provide them will all the nutrients they need. Without these nutrients, bees would not be able to produce the royal jelly required to feed the queen and rear brood. If the weather will not allow the bees to leave the hive for several days to collect pollen, and there is very little stored in the combs, it will be necessary the beekeeper to feed the bees a pollen substitute. At the same time the beekeeper will feed them sugar syrup.
The main ingredient used in making a pollen substitute is brewer's yeast. The yeast can be fed to the bees dry, but the bees can better utilize the yeast when it is made into patties with the consistency of peanut butter. The yeast is often mixed with 50% sucrose syrup to moisten the patties. The patties are wrapped in wax paper or placed inside plastic bags to keep them moist. The beekeepers that use the high fructose corn syrup will mix the patties using that syrup. Other ingredients can be added to the patties that offer more nutrients than the yeast and syrup mixture alone. Beekeepers will add casein, lactalbumin or soy flour to their mixtures. If the beekeeper use the casein and lacatalbumin it is necessary for them to watch out for lactose and over two- percent sodium. When the beekeepers use soy flour, they try to get the "debittered" soy flour that has been processed and retains some lipids, and toasted to knock out enzymes that interfere with the bees' digestion. Always make sure to check the data on the soy flour. The beekeeper will want to determine if the soy is a "high sucrose" variety or contains mostly stachyose. Stachyose is toxic to bees. Beekeepers will sometimes add a "feed yeast" like Torula to the pollen mixture to enhance the nutrients in the substitute. Most of them don't use it because of the high cost.
Pollen substitutes do not increase brood production as well as pollen sources brought in by the bees themselves. Because of the pollen substitute brood rearing will not stop all together should the weather stay bad for a while. A beekeeper will have a fatter bee when using a pollen substitute. There are some areas where pollen is scarce in the late summer and fall. If the beekeeper feeds the bees pollen substitute for a fatter bee, a fatter bee will winter better and rear more brood the next spring than their non-fed counterparts.
Bees are not fond of pollen substitutes. It must be place directly in contact with the bees and as close to the brood as possible. As long as the bees are bringing in a trickle of pollen the substitute will be eaten. If there is no pollen being brought in, the substitute will be ignored and will spoil over time. There are some commercially formulated pollen substitutes on the market that claim the pollen substitute is so attractive to the bees that they will eat it anytime the substitute is offered. No one has investigated those claims.