I started taking down my bees to small cell size 15 years ago. 10 years ago I had combs with 4.9 mm, 5.1 mm and 5.4 mm cell size in the supers. At one time I did some measurements of moisture content in honey from the capped cells in supers.

The supers were square sized for 12-frame Shallows. Single walled wood, not very thick to keep the weight down. Almost all my supers are like that. I measured moisture content in honey from cells close to the top of the frame, in the middle. When comparing the different cell sizes in the same box it was done from two frames, comb sides next to each other.

What I found then was that the moisture content in the center of the box was 1% lower than from the outer combs. This was the case when all combs in the super had the same cell size. I speculated that this was due, at least partly, to the fact that the uninsulated walls of the super made the temperature vary more in the super during day and night, especially close to the walls. During nights water drops could well be formed on the outer frames. And the honey could thus take up more moisture.

The moisture content was then 1% lower in cell size 5.1 than in 5.4. And it was 1% lower in 4.9 compared to 5.1.

The moisture content was so low in the smaller cell sizes that I became braver to harvest combs that were not fully capped. I started harvesting whole boxes even if the outer combs was not fully covered or even 2/3 covered. Sometimes outer combs were and also are today only capped at the top. Shallow frames are low, 137 mm, so it will not be as large area of ​​non-capped honey compared to a higher frame where only uppermost part of the honey is covered.

Water content in my honey is usually around 16-17%, rarely above 18%, sometimes below 16%. Before I used small cell size, moisture content was often around 18%, even though I tried to harvest only capped honey.

Project with plastic frames and insulated boxes

This year (preparations began last year) we (I and two others) started a project to test a number of different things (will probably come back with a report). The project uses insulated plastic foam supers for 10-frame Medium frames (159 mm high). All frames are supposed to be plastic with plastic foundation. Two different cell sizes are used, 4.95 mm and 5.5 mm. Thus a group of colonies have only 4.95 and another group 5.5. Not all combs are completely that way in all colonies. Next year it will.
Vettenhalt Yellow plastic frames with 4.95 mm cellsize and black with 5.5 mm.

Low moisture Heather honey

This year cell sizes were somewhat mixed for different reasons, especially in supers. So when I harvested a number of supers with well capped Heather honey combs with different cell sizes in the same super I took the opportunity to measure the moisture content again in a similar way as 10 years ago.

This time, I could compare 4.95 with 5.5. And 5.3 with 5.5 (I had some plastic frames with cell size 5.3 also for a certain reason I will come back to in the report to come).
The notes I had from the test 10 years ago I have not found. But I found those I made this year. They are seen in the table.


4.95 mm 5.3 mm 5.5 mm capped honey

uncapped honey


16.0% 17.0% X
2 16.5% 17.5% X
3 16.0% 16.2% X
4 17.0% 17.3% X
5 15.9% 16.0% X


Similarities and differences

The tendency that smaller cell sizes means less moisture in the honey holds. But the differences between cell sizes are smaller this time. Another difference is that the difference between the middle frames and the outer ones in supers with the same cell size was not found now with well insulated supers.

The difference between the cell sizes are greatest when 5.3 and 4.95 are compared. The difference between 5.3 and 5.5 was not as big (not per 0.1 mm cell size either).
The moisture content was for me surprisingly low considering that it was almost pure heather honey in the combs checked. Usually Heather honey has higher moisture content, probably due to it’s gathered late in season when temperature difference between day and night is bigger. But it was unusually warm in August this year when the Heather was in bloom and remperature was not very low in nights.

When trying to understand the results I think it helps being aware that when bee colonies build their own combs without the help of foundation many have observed they build (when they are adapted after a period of perhaps several years) mostly between about 4.7 and 5.1 mm cell size in the brood nest and 5.2-5.5 (approximately) in honey area.

When the bees have collected a lot of honey for the winter period, most of the empty cells are small. When spring comes the first brood is reared in small cells. Low moisture honey is closest to brood then. Is that of any importance for the bees? Later in season some brood is reared in slightly larger cells as well. Towards the end of the season the queen lays almost only in small cells again.

Cell size affects water content
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10 thoughts on “Cell size affects water content

  • October 26, 2015 at 17:48

    Good report that emphasizes the positive effect of small cells on honey as well (beside the tendency to reduce the mite number by one half, see earlier blog) on the basis of solid data. There are 2 aspects for this findings:

    1. For the beekeeper: honey with lower moisture can be stored longer or fulfill higher quality requirements (at least in Germany 18% is highest for DIB honey)
    2. the impact for the bees: This was the question you have raised in the end of this blog. My guess is, low moistude means less probabilty for yest or lower tendency of microbial load.

    Have you any clue about the reason for the lower moisture for small cells. Is this the physics of the 4,9mm wax comb or are the bees more active in honey production?

    And I have a second question. To me it was not clear, what the difference between plastic combs and wooden/wax combs is? Are you able to judge on this as well?
    One may find an answer or at least evidence for the upfront mentioned question, what the root cause of your finding is, either physics or bees…

    • October 26, 2015 at 18:49

      Yes Rüdiger, very often lower moisture content is positive. But sometimes it can be too low, or can it? At least it may cause more difficulties in extracting, at least when it comes to thixotropic honey like Heather honey.
      At the end of winter brood rearing has started with the bees and when the bees are burning honey for fuel they produce carbon dioxid and water moisture. And then they need honey that they can eat easily. Too dry honey is in this case not so good, but the moisture produced will sit as water drops on the capped honey and help the bees to take it, so very dry honey may not be of so much concern for them.
      I think I can guess why small cell honey has lower moisture. The total surface area of all cells on a combside is much bigger when there are small cells built on it. There are more in and outs so to speak. More cell walls. And this is of importance when nectar is coming into the hive. Nectar is at first spread out as a thin layer in empty cells and then the bees are fanning to lower the moisture. As the total area is bigger per comb more nectar can be spread out in the first phase of lowering the moisture content. Next phase means that some more nectar is put into the cells. And when the sought moisture content is achieved the cells are filled and capped. Definitely the bees can handle a strong nectar flow for getting a low moisture content before capping the honey. In such a case a lot of surface area is needed for the first phase of decreasing moisture.
      I didn’t try to find out any difference between plastic and wooden/wax combs. And I’m not sure there is any in this case as the cells in both cases are wax. Though there seems to be a difference between well insulated and not well insulated boxes. In not as well insulated boxes the outer combs will have somewhat higher moisture content than the middle ones.

      • October 27, 2015 at 17:09

        OK I thought plastic combs consist totally of plastic (like Rovergarden or HSC). But the one you tokk have been only plastic for the matrices? and the rest wax built by the bees?
        I mean I get your point for using plastic, as it favors honey harvest for heather honey.
        On the other hand plastic combs might have plasticers that may go into the honey. But as we used to say in Germany: You have to die one dead…

        And thanks for your explanation of the reason behind your finding, sounds very plausible!

        • October 27, 2015 at 17:25

          The yellow plastic combs 4.9 are from Mannlake:
          The black plastic 5.5 are Greece from Anel. But I don’t think you can buy them anymore. The brown ones, 5.3, are Finnish.
          Yes, the foundation is plastic. They are not fully “drawn”.
          No, I didn’t use the plastic because it’s better when extracting Heather honey. But that’s true. I used it because I’m part in a project where we use only plastic frames like these. The reason is to minimize the drone comb. Also to get better control of the cell size. I will come back concerning what the project is all about.
          I know the drawbacks of plastic and in general I don’t like plastic, due to the continent of plastic in the Pacific ocean. But there are advantages sometimes. The trend for degradable plastic is what we have to support.

          • October 28, 2015 at 10:24

            Indeed Eric, plastic and food/environment is and huge own topic and I won’t open this box ……
            I’m curious to learn about this project your are involved!

  • October 27, 2015 at 06:21

    I always enjoy your posts and your ability to find the hidden questions in beekeeping. I had never thought of a varying moisture level between cells sizes, but I also don’t own a refractometer. This gives me some questions though: commonly large storage cells are used for honey along with drone production, at the middle edges of a natural hive. Have you though why it might be more advantageous to the bee to store in larger cells? Is there an advantage to having a slightly higher moisture content closer to the margins of the hive?

    I wonder because I rarely see bees doing many things that are accidental. I understand it may be advantageous to the honey producer but maybe bees have a different use for it.

    I love your work so please keep doing it!


    • October 27, 2015 at 09:48

      Thanks for the nice comment. I love for posts as well on Facebook, embracing the feral bees around you and being treatment free.
      Why the bees produce drone sized cells where they do I think has more to do with drone production than honey storage, but they use them for honey as well when needed. Making bigger cellsize demands less material, so when nectar flow is heavy it’s quicker for the bees to make bigger cells and store the honey. You also see a swarm that begins making comb that the cellsize often is around 5.3. Those first cells are used to store the honey the bees bring with them. The more they build the smaller the cells get, for the queen to lay in. Later the bees often reconstruct the nest where they keep brood to fit them better. That’s what my TBH-friend Johan Ingjald has told me. Honey with higher moisture is easier to move, that’s what I can come up with.
      When the heavy flow has stopped the bees then will have honey’s with some different moisture. Still they make brood to replace the bees that have worked hard and it’s easier to take the honey with high moisture making yelly or diluting it to larva food for workers. When resting period is coming close, the cold period here, the bees move that honey closer to the core of the nest where the sit still, where the cells are smallest (Ingjald again).
      You are right, bees produce varying results of the thngs they do, but rarely make it accidental. There is a reason. And we are wise if we try to find it out.

      • October 27, 2015 at 11:18

        Hm, Tyson, reconsidering your thoughts about dronebrood at edges. Could well be it is built during heavy flow as well. Drone comb often are. And used for honey storage at first, and then eventually for drone brood, and maybe later reconstructed.

  • November 5, 2015 at 12:16

    Very interesting … and relevant for our bees here in the West Highlands of Scotland.

    • November 5, 2015 at 21:28

      If you try it, please share it. Especially when you have late flows and cold nights I think it’s especially helpful.

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