Condensing Hives with Anne Frey (308)
For generations, many northern beekeepers have been taught that winter colonies need upper ventilation to allow warm, moisture-laden air to escape. But what if that familiar advice is working against the bees? In this episode of Honey Bee Obscura, Dr. Jim Tew welcomes Anne Frey to explain the condensing hive concept and why it has caused Jim to reconsider some long-held wintering practices.
Anne explains that a condensing hive isn't a special piece of equipment. Instead, the concept relies on substantial insulation above the colony while allowing the hive walls to remain cooler. Moisture produced by the bees can then condense on those walls rather than on the ceiling, where water might drip back onto the cluster.
They also discuss eliminating—or greatly reducing—the traditional upper entrance, the role of elevated CO2 in lowering winter metabolism, and why moisture inside the hive isn't automatically harmful. In fact, bees may use condensed water to help consume stored honey.
Anne adds an important practical caution: without an upper exit, dead bees, snow, or ice can block the lower entrance. Her own approach leaves a very small upper opening as insurance.
Jim and Anne close by considering insulating quilts, warmer climates, and whether top insulation might even help colonies during summer heat.
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Thanks to Betterbee for sponsoring today's episode. Betterbee's mission is to support every beekeeper with excellent customer service, continued education and quality equipment. From their colorful and informative catalog to their support of beekeeper educational activities, including this podcast series, Betterbee truly is Beekeepers Serving Beekeepers. See for yourself at www.betterbee.com

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Thanks to Bee Culture, the Magazine of American Beekeeping, for their support of Honey Bee Obscura. Available in print and digital at www.beeculture.com
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Music: Heart & Soul by Gyom, All We Know by Midway Music; Christmas Avenue by Immersive Music; original guitar music by Jeffrey Ott
Episode artwork created by Jeff Ott with ChatGPT by OpenAI. (Jim's regular cartoonist, John Martin, is on vacation and will be back!)
Copyright © 2026 by Growing Planet Media, LLC

0:01 Listeners, it's that time of the week. Last week I had the pleasure of going to the Ohio State Beekeepers Fall Meeting. and I sat in on an official discussion of the condensing hive concept. Then it has become a procedure that evolved during the years that I was kind of offline working with my wife. But now I'm trying to catch up. I've got Anne Frey here. Anne say hi. Hi Jim. Hi everybody. Anne has had experience with this high of concept and she's agreed to educate me and you About some of the characteristics of it.
0:41 If you don't mind hanging on for a while, we'll talk through this. Beekeepers, I'm Jim Tew, and I come to you here once a week at Honey Bee Obscura, where today Anne and I are going to try to talk about something you'd with plain talk beekeeping. Welcome to Honey Bee Obscura, brought to you by Growing Planet Media, the producers of the Beekeeping Today podcast. Join Jim Tew, your guide through The complexities, the beauty, the fun, and the challenges of managing honey bees. Jim hosts fun and interesting guests who take a deep dive into the intricate world of honey bees.
1:22 Whether you're a seasoned beekeeper or just getting started. Get ready for some plain talk that'll delve into all things honey bees. And since I was out of the game for a while, when did this concept become a thing? Well, I'd say around twenty twenty-one. I was um listening to an interview that David Peck here did of Bill Hesbach And that was the first time I became aware of it. It was probably building up in twenty twenty. It's something that had a lot of attention just after that, but Not so much now, but I think maybe it's become uh common knowledge.
2:04 But for beginners who are just starting or people who didn't quite understand it, we'll we can go over the condensing hive concept I wish you would do that, if not for the listeners for me. Sometimes at shows when Betterbee is at uh conference and we're in the vendor area, people come up and they say that they want to see a condensing hive or or to tell them about the condensing hive and and the first thing I have to say is it's a concept. It's not a special hive basically the concept is that in cold regions, you know, we're both in cold regions, the bees during the winter they stay very still and the moisture from their breath is let off into the hive inside, and on the chilly inside surfaces of the hive, this water vapor touches that cold surface and then it condenses.
3:03 And this is all natural, you know, it's it's good for bees to have moisture on the surfaces. But the idea of using that action of water to condense is just that we want to have insulation above the bees. It's not nearly as necessary to have it on the walls And that way the moisture condenses on the walls. It doesn't condense on the ceiling and then drip back down on the bees or heaven forbid, freeze and then form icicles and then later on drip down on the bees. So insulation above them is the key thing. And the second thing is zero upper entrance, upper hole.
3:45 You know, maybe that little notch in the inner cover is a pretty standard thing for people to leave open during the winter But that's the second detail is that should be closed off. So there's no as Bill Hesbach would say an attic window open all winter. So that's the core of it. We can get into the nitty gritty of what happens in physics, you know, when water condenses and things like that or misconceptions. What have you heard, Jim? I sat through the discussion that the presenter, I don't have the program with me, gave. There's a apparently quite a bit of insulation on the top.
4:27 It's not just a you know a piece of styrofoam or an insulated top. There was do I dare say I remember her saying R thirty four? Wow, that's a lot. Well, when bees live in the wild in a tree trunk They've got the entire height of the tree above them as insulation. So I'm not, you know, I'm not surprised that it's more than What do we usually have on the top of our hives inside of R five, one inch one inch thick rigid foam? I've been a proponent of doubling that up, but that would only be R-10, R-34 you know, why not? And also you could put this insulation on the exterior of your beehive's roof, you know, that out or covered.
5:18 I would think so. I was thinking you'd have to have bricks or something to keep it from blowing away, especially if it's just expanded polystyrene foam kind of stuff. Yeah, it could be anything. But I would say y definitely some uh straps. Bricks on top of a really lightweight item might just make it top heavy. Yeah, top-heavy, wiggle and then it would slide they would slide off. But Yeah, I love the straps on the hives anyway. So uh yeah, so the idea is that moisture inside the hive is natural. I know that quite often when people find that they have a dead colony and they're looking at the the corpse of the cluster, they're like, Oh, this is all wet.
6:02 Oh, it's oh, there's mold and the moisture killed my bees, you know, so that's a mistake that I've heard many times and I used to make that mistake when I was a beginner too, but even with a biology degree it didn't occur to me that just dying is going to release a lot of moisture. if mold gets a chance to start growing and there's no warmth or circulation from the bees, no air circulation, that mold is gonna grow. So That's more of a after death kind of scene than a cause to death, no. Well, I don't know how to put my questions together because at its core level this concept attacks basic tenets that have been in place My entire beekeeping life that bees have to have an upper entrance.
6:50 Just like it says to let out that moisture-laden air is how I always worded it. Yeah, I used to teach that too. it was just it was what I was taught. But his comparison of having an attic window open all winter and you know, that means that you're going to have a higher heat bill For the bees, the heat bill is honey, you know, so they're gonna just be eating more honey, they're gonna have this extra stress. The other weird thing that I learned happens when the upper entrance is open is that you're letting out their air and their air, which they prefer in the winter, to be a kind of a buildup of CO2 which keeps them dormant.
7:34 By letting this constant trickle of air leave the hive, it's actually more oxygenated hive And that makes them more active than they naturally would be, because their natural state is really deep dormancy with this CO carbon dioxide buildup. And that's what they evolved with to get through these cold winters. I have seen that when I had my nine frame observation hive set up that would winter over most years. And they would just be crazy to propolize all the vents, all the intakes, they closed everything. And I thought, Oh my heavens, you are going to be breathing nothing but CO2 So I would try to open it up.
8:21 I'll I tried to figure out ways to punch the vent screens open and let them get that precious air. And then I did read later on that they do want to winter in a high level of CO2, high for you and me, and that lowers their metabolic rate, and they sit there at a lower idle. burning less honey in this high CO two area. Yeah, I never knew anything about that until just a few years ago. And it's just our I think a lot of it is our human mistakes of we're thinking that everybody every creature in the world wants what humans want, you know, and bees, insects, that the inside of the hive.
9:06 It's not what we want, you know. They actually prefer this humidity in there. They want this moisture collecting on surfaces just just outside the cluster where it's chillier and then they lick the moisture up in order to easily get their honey out of the cells. That's another whole detail is that they they're thirsty in the winter, they need this extra moisture to eat that thick, thick honey. You know, they never bring in thin nectar or anything thin during the winter. They need that stuff that came out of their breath, condensed on the surfaces, and then it's it's like an extra thing that's available to them right when they need it.
9:49 Let's take a break in and hear from our sponsor and pick up at this concept of mistakes that we're trying to correct. For more than 45 years, Better Bee has proudly supported beekeepers by offering high quality Quality, innovative products, providing outstanding customer service, many of our staff are beekeepers themselves, and sharing education to help beekeepers succeed. Based in Greenwich, New York, Betterbee serves beekeepers all across the United States. Whether you're just getting started or a seasoned pro, Betterbee has the products and experience to help you and your bees succeed.
10:34 Visit betterbee. com or call 1-800-632-3379. Betterbee, your partners in Betterbeekeeping. And pick back up where you were on I said correcting mistakes because I made the comment at that meeting when I was giving my presentation That as you go through bee life, you think by the time you get to be an old wise beekeeper, you pretty much got all the details worked out And it's been my realization that as an old wise beekeeper, you're correcting old mistakes that you didn't know were mistakes. I I was taught that in the earliest days of my B career that drones were were expensive for the colony and I should destroy all the drone brood I could find.
11:23 because all they did was mate with the queens occasionally, and otherwise they just consumed honey. So how I did torment beehives, tearing down all their drone comb just to make them frenzied. to put it back wherever they could. You win some and you lose some. But all through the years I have always had upward ventilation because you said it correctly, I think. That's human nature You want a warm insulated ventilated house. You don't want to keep breathing all your cooking odors and whatever. Yeah, yeah. Even in the winter, I mean we personally we don't leave an attic window open constantly, but we definitely are letting air in every day we're opening the doors and using our house and if it was closed up all the time we would be like, Oh, it's so musty in here.
12:19 Let's open a window or crack just to get some good air in. Yeah, so we've got that stuck in our heads and I think a lot of the uh the ideas of other things in beekeeping are our mistake of trying to relate the bees life to our lives and it's It's natural to do that, but I like the idea that, you know, we learned that about drones, we learned this about the cycle of the air inside the hive. We're always We're always learning. You know, it's like yeah, we did go through decades of thinking, keep that air moving and make sure they get oxygen and it's like Well, now we've learned something different. In five years we'll learn an another new thing about bees or tomorrow.
13:03 And you had an interesting concept as we were preparing for this segment. about some kind of upper entrance for a unique reason. I'd like for you to go into that. Yeah, it's sort of um a beware moment I'd like to share because uh with the condensing hive and the logic of it and the physics of it There's also the bees' life during the winter, which means the cluster is moving up, bees are dying bit by bit in a natural inevitable progression, you know, a few are falling, a few are falling to the floor.
13:43 And no bees are tidying that up like housekeeper bees usually would every day if it was warm. So you've got an accumulation of dead bees at the bottom may be blocking the door. And who knows if water running down the sides has gotten into them and made a frozen ice dam down at the bottom. So If bees have no exit at the top for their own flights, like warm days in late winter and their entrance at the bottom is blocked, then what are they supposed to do? We saw this happening again and again and uh we can't get out and sweep our entrances clear with a hive tool for every hive we own.
14:29 Hobbyists can do that. So I would say if you're really going whole hog with the condensing hive and zero upper entrance, don't forget to occasionally sweep out your entrance with your hive tool or a yardstick or something My adjustment to the concept is that I'm not going to be able to do that, so I'm I'm leave the upper entrance but I leave it very, very small, like one B. That notch is probably like four bees wide. That notch I'm talking about is that kind of missing chunk on the rim of the inner cover. So that's the notch. So I just uh have made that smaller.
15:11 I've also made the inner hole smaller, that kind of hot dog shape hole in the center of the inner cover. Made that really small by putting our record card over it So I'm just trying to get the best of both worlds. Well, that's an interesting concept. You didn't mention snow. It only takes a light snowfall, an inch of snow or so, to pretty much cover the bottom entrance. It depends too on how much snow you're getting. All you folks in warm climates don't have to sweat it with that. Yeah, this is all about northern people uh what we're doing today. The snow is porous enough that air will go through it, but it's when it gets compressed or if it's an ice storm or something, and that's actually a solid dam down there.
15:56 You know, that's what I'm worried about They could be in three feet of fluffy snow and still be getting a little bit of air exchange. The old people used to use something called an insulating quilt. It was a heavy canvas bag filled with newspaper litter or something, some kind of filler. And they'd put it on top during the winter and then what they wanted was for that to absorb the moisture and freeze, and then as the weather changed, that moisture would be re-released back into the brood nest area and would be available. That that whole concept of an wintering quilt has gone away and been replaced with this insulation concept There hasn't been a wintering quilt since the nineteen twenties or thirties that I know of.
16:49 Well, some people still do that kind of thing. It's always a homemade item. Maybe these days they're filling it with wood shavings But they're keeping the moisture in. It's sort of like a softer thing that things are it's not just condensing on the rigid sides of the hive or the rigid ceiling. It's being absorbed into this soft stuff and then not lost, it's re-released. So there is a small club of people, really not a club, but a group that really loves those sorts of upper quilt boxes or or What would you call it? You called it a blanket? An insulating well, yep. Yeah, that's still a kind of a niche thing, but it's valid.
17:34 And we've only got a couple of minutes left and I want to know if you can suggest anything for people who live in warmer climates than we do. Do they need all this insulation concept or do they have the same issues In a different way? They don't so much. I've visited people in Georgia and they would they were concerned about the occasional night that was, you know, down to thirty two and then the next day is another flight day. It's the lack of flight days is our issue. Down south it's really rare for them to have a week of no flight days. So I d I don't think insulation or worrying about any of these things is a southern thing at all, but it couldn't hurt to have some top insulation maybe five or ten are it can't harm anything.
18:24 Keep some stress off the bees and anything you can do to decrease the bees' stress is a good thing. That's true. We're out of time, but I've just got to add one more thing, and that is would insulation help hot weather beekeepers in the summer When it's 103 outside or at ninety-eight or whatever and the bees are trying to maintain and the bees are all clustered out front Would summer insulation be anything? I'm I'm just totally out in the right field now. Seems like that metal telescoping outer cover is so hot if I accidentally touch it uh that that heat has gotta be transmitted into the hive and put more work on the bees trying to fan I think top insulation, but not entire polystyrene hives, 'cause if you get a lot of heat trapped inside of a well insulated house, you know it's hard to then get your house cool again.
19:27 That's just me talking off the cuff here. That's just me having grown up in the South and living in the Midwest now, upper Midwest. Yeah, you have the best of both worlds. That's the best of both worlds. We need to let our listeners go, Ann. They've got other things to do. I've enjoyed talking with you about this and I'll keep pondering it and considering these things. It's a this a change for those of us who do it the old way to go through. It's always a new thing, always learning. It's been good to talk with you Jim. Tell everybody bye and Bye everybody. Bye everybody. Until next week.
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