What makes Honeycomb Dark?
OK… So you’ve been inspecting your beehive frames for a while now, and you can’t help noticing that frames with brood cells look darker in places. After a while, and certainly after your first season of beekeeping, you’ll see that some cells become dark. With time they may be almost black in color. There can be a striking difference between light colored honeycomb and dark brood comb. I remember when I first saw this I was quite puzzled...
So what makes honeycomb dark? Dark honeycomb is found where cells have been used for brood rearing. The dark color is thought to be produced by the repeated use of these brood cells and the debris and propolis which builds up over time. Cells used only for storing honey remain light in color.
If you find dark beeswax in your hive, don’t worry, this is perfectly natural. But what should you do about it? Should you just leave it, or does it need to be removed? And what about harvesting dark capped honey and comb… Can you eat this?
So many questions… The mind boggles!
Dark Honeycomb in my Hive
Brood comb becomes darker and darker after each cycle of young bees emerge from the wax cells.
Your brood comb will become distinctively dark in comparison to cells used only for honey. You’ll notice this in particular if you use a queen excluder to separate brood boxes from supers. The wax in your supers can remain light in color for years to come.
But you’ll also notice a difference in color across the surface brood frames. The queen generally lays brood in the center of the frame. Over time the middle of the frame darkens, while honey cells near the top and edges of the frame stay light in color.
This darkening actually corresponds to a roughly spherical brood nest shape in the center of the hive. Honey bees do this so that they can cluster in a ball to keep brood warm, especially during cold months when they form a winter cluster. As the colony grows, beekeepers need to add extra brood boxes to provide more space. As the season progresses the dark colored honeycomb expands as the amount of brood extends to the new brood frames.
The dark color of brood cells seems to be caused by the huge amount of activity that these cells endure. A brood cell is capped at the end of a period of about 9 or 10 days. During this time, worker bees are coming and going hundreds of times a day to feed larvae. That’s a lot of traffic! And a lot of tiny bee feet covered in pollen and stuff. I’ve heard it said that the interior of an uncapped brood cell will capture all kinds of debris from within the hive, and that this contributes to the darker color.
Another probable contributing factor to this dark color is the repeated build up of bee cocoons inside the honeycomb cells. Bees do a pretty good job of cleaning up the inside of cells after each cycle of new bees emerge, but they have trouble removing all of the cocoon. And cocoons are pretty sticky, so that means more debris and hive dust. Typically a worker bee evolves from egg to adult in 21 days. So that’s a new cocoon being deposited every 21 days during the brood rearing season. Honey bees have no choice but to leave cocoon parts inside the cells and make them ready for the next generation of young bees. The repeated build up of cocoons is thought to add to the dark color of the beeswax.
When worker bees prepare wax cells for the queen to lay new eggs, they brush and polish the interior walls of the cell using propolis (this is also known as bee glue and is made from the resin from tree buds, mixed with beeswax and saliva). This creates a hygienic foundation for new brood because it helps to prevent the growth of bacteria and fungus inside hives (propolis has antibacterial, antifungal and antiviral properties).
Propolis varies in color but the most common is dark brown. I’m sure you can see what this leads to… Yes, the build up of propolis, and the frequent reuse of the cells renders the color of the beeswax darker and darker.
So to sum up, the accumulation of hive debris, abandoned cocoons, and propolis is the most likely cause of darkened comb.
Can you eat dark honeycomb and dark capped honey?
Cells which were previously occupied by brood can be converted by bees for use as honey and pollen storage. If you’re interested in making cut comb honey you may be wondering if this kid of honeycomb can be consumed.
Here’s the buzz...
If you’re accustomed to eating comb honey then you may also enjoy eating brood honeycomb. Apparently it tastes quite different to light honeycomb. Indeed in some parts of the world this dark comb honey is prized more than other types of honey. The build up of pollen etc., from the brood rearing process is said to impart additional beneficial enzymes.
Most beekeepers don’t think of dark honeycomb as a worthwhile harvest. Next time you find some dark honeycomb, you might want to give it a try!
You can either filter the honey from the dark beeswax or make comb honey which includes part of the beeswax. Cut comb honey is one of the easiest ways to recover your honey crop. You don’t need to uncap, extract and filter it. But keep in mind that if you do want comb honey to be your major crop you’ll need to use frames in your supers which don’t use plastic foundation.
What to do with old brood comb
I’ve heard of beekeepers keeping darkened brood comb in their hives for many years without problems. But this is probably a thing of the past. It’s not that bees don’t like dark beeswax (in fact I believe some beekeepers use it to help catch swarms), rather, there are more reasons to remove old wax than before.
It’s now common practice to withdraw the darkest areas of old brood comb in beehives. This is because of the possible build up of traces of disease such as nosema and foulbrood. But nowadays there’s also the risk of accumulating pesticide residue in the old wax. In the UK for example it’s recommended that you don’t use brood comb for any more than three years!
It’s interesting to note that brood comb cells get smaller and smaller as the cell walls get thicker because of the repeated layers of propolis and cocoons. I’m not sure if the bees mind this, but i guess things could get pretty cramped after a few years!
Replacing old brood comb
The best way to replace old brood comb is to have an annual plan of some kind. If you follow the recommended “three year old brood comb” limitation, that means each year you should remove one third of the darkest beeswax on your frames. In this way you naturally rotate the hives stock of brood comb.
It's possible that you have frames which are almost full of old dark beeswax in the middle of the brood box and you want to replace them entirely. To do this you need to exchange them with prepared drawn comb.
But how to you get replacement drawn out comb?
One easy method would be to place a queen excluder on top of your brood box, then put another brood box on top of this with frames of foundation (in the same way you would for a honey super). Do this during a good nectar flow so that the foundation gets drawn out quickly.
The term “Drawing out” is the beekeeping term for how bees build wax comb. Foundation is often placed into frames as a basis on which bees can “draw out” wax comb. They can be made of plastic or wax, or sometimes beekeepers use no foundation at all. Foundationless frames have wires running through them as a guide for bees draw straight honeycomb.
When your upper box full of honeycomb you can carefully extract the honey then put the frames to one side to be used as replacements when needed.
To replace an old frame, at the end of the beekeeping season, move the darkest frames of wax to the outside edges of the box. This will ensure that come spring time, those frames will be free of brood, since during the winter the bees will cluster in the center of the hive, not the extremities. Then, on a nice warm day in March, you can replace those dark brood frames with the new ones that your bees drew out during the honey flow.