Freeze combs to prevent wax moth damage
The purpose of freezing wax combs is to kill the eggs and larvae of wax moths. Wax moths can destroy beeswax combs, especially combs in weak colonies and those in storage. A strong colony of bees does a good job of controlling the moths, but a weak colony can become overrun.
Although the moths cannot survive long periods of cold, a healthy hive stays fairly warm all winter long. The moth larvae chew cavities in the frames, spin their cocoons, and spend the winter as pupae kept warm and toasty by the honey bee cluster. In the spring, they emerge as adult moths.
The larvae of wax moths destroy combs while they search for food—mostly cocoons of bee pupae and bits of pollen. For this reason, comb that once contained brood is much more susceptible to attack by wax moths than comb that has contained only honey. On occasion, however, the moths will destroy comb that has never contained brood. Such is the lot of beekeepers.
Freezing overnight will destroy all stages of wax moths. It is not necessary to store combs in the freezer—only to freeze them overnight. But freezing will not prevent the immediate re-infestation of wax moths if the comb is placed where moths can reach it.
Combs that are frozen and immediately returned to the hive will immediately become re-infected, but a strong hive will manage them. Combs frozen and placed in a shed or garage will also become re-infected if adult moths are in the area. Only combs kept away from adult moths will remain moth-free.
Comb can be frozen even if it contains honey. Honey is low in moisture and will not expand and break the cells. If handled carefully, it can be frozen and thawed with no loss of quality and no change in appearance.
Comb honey producers routinely freeze their honey before packaging it. Even if the probability is small, no comb honey producer wants creepy crawlies writhing over the lovely comb—and certainly no customer wants to buy it. So combs are frozen and thawed before going to market.
But producers of extracted honey can freeze their frames as well, especially if they want to delay extraction until the entire crop is in. As long as the thawed comb is kept away from moths, it can be easily held until extraction time.
One word of caution about freezing: condensation. Condensation will form on combs that are taken from the freezer. If the combs are stored before they dry, mold will appear in a spectacular display of gross. An easy way to prevent mold is to wrap the combs tightly in plastic wrap before you place them in the freezer. After you remove them from the freezer, allow them to come to room temperature before removing the plastic.