Dark honeycombs are a natural feature of established honeybee colonies and are usually the result of brood combs being used repeatedly over time. As comb ages, it gradually changes from pale yellow to deep brown or almost black. In some cases, honey stored in these older combs may also appear darker, especially when it comes from nectar sources that naturally produce rich, dark honey.
What Causes Honeycombs to Turn Dark?
If you are inspecting a hive for the first time, discovering dark or black combs can be surprising. New comb is almost white or light yellow, but brood combs begin to darken after a single season of raising bees. With continued use over several years, these combs can become nearly black. Honey storage combs, on the other hand, often remain light-coloured for much longer because they are not subjected to the same level of activity.
Several factors contribute to the darkening of honeycomb:
1. Repeated Use of Brood Cells
The primary reason brood comb becomes dark is the repeated rearing of successive generations of bees. Every brood cycle leaves behind tiny traces of cocoon material, propolis, and other debris inside the cells. As these residues accumulate, the comb gradually changes from light yellow to dark brown or black.
2. Constant Bee Activity
Brood cells are among the busiest areas in the hive. Nurse bees continuously inspect, feed, clean, and tend developing larvae throughout the day. Once brood cells are capped, workers continue to care for the surrounding brood until the young bees emerge about 21 days later. This constant movement, combined with pollen, wax, and other particles carried on the bees’ bodies, gradually stains and darkens the comb surface.
3. Cocoon Residues
Although honeybees are exceptionally clean insects, they cannot completely remove the thin cocoon lining left behind after each brood emerges. Every new generation adds another delicate cocoon layer to the inside of the cell. Over time, these layers trap dust, pollen, and other fine particles, making the brood cells progressively darker and slightly smaller.
4. Propolis Deposits
Worker bees disinfect brood cells with propolis before the queen lays new eggs. This sticky resin, collected from tree buds and mixed with wax and bee saliva, has powerful antimicrobial properties that help protect developing brood from disease. Since propolis is usually dark brown, repeated applications contribute significantly to the gradual darkening of older brood comb.
5. Royal Jelly
Royal jelly is the nutrient-rich food produced by young worker bees to feed developing larvae. While all larvae receive it during their early stages, queen larvae continue to be fed royal jelly throughout their development. Because royal jelly ranges in colour from creamy white to yellowish or light brown, repeated exposure may contribute slightly to the gradual staining of brood cells, although its effect is much less significant than cocoon residue and propolis.
Why Does Some Capped Honey Look Dark?
Honeybees are remarkably efficient recyclers. Once brood has emerged, the empty cells are often reused to store pollen, nectar, or honey. As a result, honey stored in previously used brood comb may appear beneath darker wax cappings than honey stored in newly built comb. This often raises questions about whether the honey is still suitable for consumption.
Honey harvested from older brood comb typically differs in appearance from honey stored in fresh comb. The darker wax results from years of accumulated cocoon layers, pollen, and propolis rather than from changes in the honey itself. Some beekeepers believe that honey from these combs contains additional pollen and naturally occurring compounds that contribute to a richer flavour and increased nutritional value.
Opinions about dark comb honey vary widely. In some regions it is considered inferior because of its appearance, while in others it is highly valued for its robust flavour. However, many beekeepers replace brood comb every two to three years because old comb can gradually accumulate pesticide residues, environmental contaminants, and disease spores. Regular comb replacement helps maintain colony health and reduces the buildup of unwanted substances within the hive.
Conclusion
Dark brood comb is a normal and expected part of a healthy honeybee colony. Its colour develops naturally through repeated brood rearing, the accumulation of cocoon layers, constant bee activity, and the application of propolis. Contrary to a common misconception, the dark colour has nothing to do with bee waste, as honeybees maintain exceptionally clean brood nests and remove waste from the hive whenever possible.
Older, dark comb also has practical advantages. Many experienced beekeepers use it when baiting swarm traps because swarming bees often prefer comb that carries the familiar scent of a previously occupied hive. While dark comb itself is generally safe for both bees and humans, replacing old brood comb on a regular schedule remains a good management practice to reduce the long-term accumulation of contaminants and support strong, healthy colonies.