feeding bees

The perils of sugar syrup: it’s not that complicated

After fielding beekeeper questions for eleven years, I have a decent idea of what confuses beginners. When it comes to puzzlement, nothing beats the perils of sugar syrup. Questions such as “How do I make sugar syrup?” outnumber “How do I control varroa mites?” about 2:1. And there it is, one of syrup’s revered ratios, along with 1:1, 3:2, and 5:3.

This article first appeared in American Bee Journal, Volume 161 No 1, January 2021, pp. 59-62.

Before I begin to dismantle the whole concept of sugar syrup ratios, let me say there is absolutely nothing wrong with them from a management point of view. Beekeepers have been using standard ratios of sugar to water since sugar was cheap enough to feed bees. Most beekeepers have fed sugar at some point in their careers. Some do it regularly, some do it only when needed. That’s fine. I do not intend to examine the moral implication of feeding syrup to honey bees.

Sugar syrup guidelines

The best thing about these ratios is the guidance they provide to beekeepers. A light syrup in spring enhances brood rearing as would an early nectar flow. A heavier syrup in autumn is easier for bees to process because less water needs to be removed. Conceptually, these guidelines work well and have enhanced the lives of countless colonies.

However, based on questions I’ve read, it’s obvious that new beekeepers do not understand the role sugar syrup plays in colony management, nor how precise the measurements must be to properly care for bees.

For example, a woman recently explained how she meticulously measured the ingredients for 1:1 syrup, but before she finished, her husband swept spilled sugar from the table and dumped it in the pot, “completely ruining the entire batch!” She wanted to know if I could calculate a fix, estimating he added an entire teaspoon to the gallon of syrup.

I can only imagine the firestorm this created and hope she didn’t deploy the rolling pin on husband number whatever. But this is a typical question, along with others about reading the meniscus, sufficient stirring, using sugar beyond its pull date, chlorine in city water, and allowing syrup to sit on the counter overnight. The complexity arising from the simple act of mixing sugar into water is astounding.

Worse, the first question that usually follows these I-screwed-it-up stories, is “Will it kill my bees?” Now I’m the perplexed one. How, exactly, do they think it might kill them?

The perils of sugar syrup showing a bag of sugar.
Problems in the bag.

The origin of the ratios

I have no clue who first suggested the now-familiar sugar syrup ratios or when. Whoever did was on to something because the ratios are easy to remember and work well. But any recommendation to feed syrup at a specific ratio of sugar to water is a guideline, a rule of thumb, an estimation, and whoever suggested the idea was a human, not a bee. The notion of a specific sugar concentration is foreign to bees simply because it’s foreign to plants.

Every plant is different

All nectar-producing plants have their own recipe, a genetically-driven range of sweetness. Some nectars are low in sugar, such as that produced by pear flowers. Others are high in sugar, such as the nectar from certain blackberries. Most are somewhere in between, but I doubt any are exactly 1:1, 3:2, or 2:1.

Furthermore, the amount of sugar in the nectar of each species can vary with environmental conditions. It may change from morning to evening, in overcast weather vs sunny, on hot days vs cool ones. Add to that windy days vs still ones, sun vs shade, and humid vs dry. Soil type can make a difference, too, as can soil fertility. Nectar concentration can even vary among the blooms on one plant. There is no immutable ratio of sugar to water in nectar, so why do we think sugar syrup must have a precise percentage of sugar?

The honey bees did not provide the specifications for syrup, and they don’t carry mini hydrometers to test its specific gravity. While the bees are ingesting infinite concentrations of sugar to water, we are home micromanaging their syrup, measuring and stirring and tweaking, hoping to arrive at some magical ratio that the bees don’t give a rip about. If they could roll their large compound eyes, they would.

Averages can be deceiving

Recommendations based on averages always remind me of the government. If you look at U.S. census statistics, you will find that in 1960, the typical American family (whatever that is) had 2.33 children. In 2019, the average family had 1.93 children. Now, I don’t know about you, but I’ve never met even one family with either 2.33 or 1.93 children.

The same goes for sugar syrup. Even though we swear by 1:1 or 2:1 syrup, and we go to great lengths to make accurate measurements, there’s likely not a flower in the world that produces an equivalent nectar. If natural nectar ranges from four to seventy percent sugar, how can tossing in that extra teaspoon (or cup or pound) make any difference to the bees?

Even though the guidelines are handy and work well, we must realize that they are not edicts etched in stone. Variations in measurement will not make any difference and will not affect bee health. You are not going to kill your bees with a concentration that is a little more or a little less than the guidelines suggest — or even a lot more or less.

If you still need convincing, consider this. Bees can drink pure water and it won’t hurt them. Bees can also consume hard sugar bricks and thrive. The only difference between the two is the sugar-to-water ratio. The first is 100% water, the second is 100% sugar, and all the nectar and sugar syrups on earth fall somewhere between those two.

Significant digits

The last time I wrote about sugar syrup, I explained that you can measure your ingredients by either weight or volume. Yes, the results are slightly different. But in this application, where you’re trying to replicate a moving target, you can only approximate the composition of nectar, no matter how carefully you measure.

Since 1 cup of refined sugar = 200 grams = 7.05 ounces = a little less than 0.5 pound, and 1 cup of water = 236 grams = 8.3 ounces = a little more than 0.5 pound, you can measure by weight or volume or a little of both.

Someone responded explaining how dangerously wrong I was. And to prove it, he had taken his wife’s measuring spoons and kitchen scale and recorded everything to prove how vastly different weight and volume can be. He sent his calculations, all extended to seven decimal points, just to prove how mistaken I was.

Not only did this demonstrate a lack of knowledge about nectar and bee biology, it also highlighted a problem with significant digits. By claiming 7 decimal points worth of precision from a measuring spoon that could probably give him one, he was producing meaningless strings of numbers and completely missing the point.

Inverting the sugar

Another popular misconception involves inversion. Many beekeepers think they must invert table sugar to make it digestible to bees, or to make it more acidic so the pH closely resembles that of honey. Neither is necessary.

Let’s back up a moment and look at table sugar. Table sugar is sucrose, a disaccharide made from a molecule of glucose and a molecule of fructose. These two molecules, both of which are simple sugars, are bound weakly together. Chemicals can be used to split the molecules apart, something frequently done by bakers who are trying to achieve certain properties in their products, such as moisture retention.

Invertase, an enzyme produced by yeast, is the baker’s chemical of choice for this job. The name describes its action: it inverts the disaccharide back into its component parts by splitting the bonds between the glucose and fructose molecules. You can also split the bonds with acid, which is what beekeepers try to do with vinegar, lemon juice, or cream of tartar (tartaric acid).

Bees just do it

In truth, nearly all nectar contains much sucrose accompanied by an assortment of simple sugars, including glucose, fructose, maltose, and others. But when you analyze honey, it’s mostly glucose and fructose. In other words, the sucrose the bees collected was split into simple sugars during the honey-making process.

How did that happen? Well, it turns out that bakers aren’t the only ones with a cache of invertase. Honey bees have their own supply, right in their salivary glands. When the bees scarf down nectar and hold it in their crops, invertase is already at work, breaking down the sucrose into the simple sugars glucose and fructose. The acidity in honey is produced by several other bee-produced enzymes including glucose oxidase, which forms gluconic acid during the breakdown of glucose.

When bees eat sucrose in the form of sugar syrup, the same thing happens. The bees automatically add the enzymes that invert and acidify the syrup, so there’s no reason to do it for them. “Don’t worry,” they say, “we’ve got this!”

Cooked syrup and hydroxymethylfurfural

Hydroxymethylfurfural (HMF) is a naturally occurring organic acid formed during the dehydration of sugars, especially fructose. Under laboratory conditions, HMF has proved toxic to honey bees.

Elevated levels of fructose increase the probability of HMF formation, so something like high-fructose corn syrup is known for lots of HMF. But other things, such as inversion of sugar syrup by acids, also increase HMF by increasing the amount of fructose in the syrup. Heating syrup or honey also increases HMF, as does aging.

So how much of a problem does it cause? The numbers vary, but it seems to be a minor problem, possibly shortening the lifespans of some colony members. Cooking syrups to make fondant or hard candy is an age-old beekeeping practice that continues to this day, so the effects are not catastrophic. Still, when combined with other factors like pesticides, parasites, or pathogens, a little extra colony loss may not be desirable.

Fortunately, for those who want to avoid excess HMF, no-cook candy boards or dry feeding of granulated sugar circumvent the problem. Highly concentrated syrups, even 2:1 are harder to make without hot water, but the less heat you use, the less HMF you will create. Leaving out the acid helps too.

Organic sugar for syrup

A surprising number of new beekeepers are eager to feed organic sugar to their bees to give them the best possible diet. Unfortunately, organic sugar has a much higher ash content than regular refined sugar, and a high-ash diet in winter can increase the chances of honey bee dysentery. Apparently, the ash can capture and hold extra water in the gut, which is the ultimate problem.

The higher ash content gives organic sugar a light tan color, which you can clearly see. The extra ash is due to the way organic sugar is processed. Typical refining methods use chemicals that are not allowed by organic standards, so the entire process was reimagined in order to produce what is generally called “evaporated cane juice” rather than refined sugar. The amount of ash varies by manufacturer, but when I researched one popular brand, I found it contained 2.15 percent ash compared to 0.07 percent in non-organic refined sugar, over thirty times as much.

The problem with cold syrup

Another common sugar syrup question is “Why have my bees stopped drinking their syrup?” or worse “How can I make my bees drink their syrup?” The adage “You can lead a horse to water, but you can’t make him drink” applies here. You can’t force bees to drink syrup, you can only gently suggest.

If it’s autumn when the bees stop drinking, the syrup is probably too cold. I can’t name an exact temperature when bees stop drinking syrup, but it’s somewhere around 50 F. If bees drink syrup that’s overly chilled, they go into torpor, a state of lowered metabolic activity brought on by a drop in body temperature. Once they become stiff, slow, and barely able to move, they may fail to rejoin the cluster.

For bees that work together to maintain a minimum nest temperature, this can be dangerous to the entire colony. So rather than drink the cold syrup, they just ignore it. Syrup can be kept a bit warmer by using an internal feeder above the cluster. In that configuration, warm air from the colony rises and keeps the syrup warmer. Three-season feeders work on this principle and can be used later in the fall than external feeders. In areas with cold winters, syrup should be replaced with fondant or sugar cakes during the coldest months.

But bees can’t eat dry sugar

As anyone who feeds sugar bricks, candy boards, or granulated sugar can attest, winter bees can thrive on granulated or hard-as-rock sugar cakes. However, the surface of dry feed needs to be moistened before the bees can consume it.

To be effective, dry feed needs to be placed above the cluster so that moisture-laden warm air can condense on the surface and dissolve it. This happens naturally due to convective currents in the hive. Moisture from bee respiration rises along with the warm air and condenses on the hard sugar, forming a thin, sticky film that the bees lap up from the surface. As the outer layer is consumed, more moist air dissolves the next layer, and so on, until the bees eat the whole thing.

Dry sugar in the wrong place, such as on the bottom board, will usually fail as a food source because it’s cold down there. Bees will move into areas that are relatively warm, and the warmest place outside of the cluster is directly above the cluster. No matter how hungry they get, bees will not move down into a colder part of the hive to get food if it means risking torpor.

Sugar or trash?

Many beekeepers insist their bees don’t like granulated sugar and, instead of eating it, they take it outside like trash. Indeed, if granulated sugar is fed in warm weather when bees are out flying, they will do precisely that. If it’s warm enough to fly, it’s warm enough to break cluster and clean house. Once the cluster has dissipated, there is no longer a steady supply of rising moisture to wet the granules, so out they go.

Listen to what your bees are saying. Dry sugar feeding is a wintertime thing, not a spring or a fall thing. If you remember that, your bees won’t haul it away.

Don’t change, just think

I’m not proposing you abandon time-honored recipes for syrup or trusted guidelines for feeding. Of course not. I’m only suggesting they are meant for your convenience, not your undoing. Lighten up and realize no bee is going to complain about your quality control or lack thereof. Spend less time worrying about exact measurements and precise recipes, and spend more time thinking about how the bees will access the feed, how cold it will get, and how edible it will be.

No bee is going to reject a source of food because it’s not made to certain specifications. Well, not usually. Honey bees are known to reject the four percent nectar (1:25) that leaks from pear blossoms, even though other species, like mason bees, seem to like it. Because they have such a high need for sugar, honey bees generally select the sweetest nectar they can find that’s conveniently located, available in a big patch, and coming from a flower that suits their tongue length. You rarely see them checking the nutrition label for sugar concentration.

Worrisome thoughts

I was nearly finished writing this article when a horrifying thought crossed my mind. What if ABJ insists on precise measurements of sugar and water, say four decimal places, or worse? Worried that I might offend the powers that be, I riffled through virtual pages of the ABJ website, looking for a hint.

Then I found it. Buried in the FAQs section are directions for making 1:1 syrup: “Half fill your container with sugar and add water to completely fill the container.” Perfect! Another reason to love ABJ.

Honey Bee Suite


  • Love it! Overthinking is a common issue with beekeeping. My girls don’t seem to care at all if their syrup has been in the refrigerator for a week and brought back to room temperature before serving. I’ve even taken leftover sugar cakes and dissolved them into water/sugar syrup so they don’t go to waste. Again, no one has complained and everyone has been very receptive. 🙂

  • Worth noting that while bees might not be uber picky about ratios, hummingbirds and other syrup eating birds are; a 4 water:1 sugar closely mimics nectar without doing damage to bird kidneys.

    • So why would you put a syrup feeder where other animals could get to it? The syrup belongs in the hive where the hummingbirds won’t go.

  • Smart people are really stupid when it comes to some things. My mother used to say that experience beats book learning.

    Bees don’t write books. But people read all of these books and just don’t connect. We are not talking about putting spark plug #7 wire on #4. It isn’t that kind of a thing. Whether you give them 2-1, 1-2, 1-1, or whatever it isn’t going to kill them.

  • Great article, as always Rusty. I wish new beekeepers would spend more energy understanding mite management, rather than making feeding a more complicated affair than it is.

    • Jim,

      Beet sugar and cane sugar are chemically identical. However, the people who don’t like GMO products prefer cane sugar because it’s not genetically modified, at least not yet. Beet sugar usually is GMO, but not always. Personally, I’ve used beet sugar for my bees for more than 20 years and will continue.

  • I always make sugar syrup in the fall and in the late winter. I have a half box that I place on top and put the feeder in there to keep it at a temperature that makes it warm for them to use.

    Last year I tried to use “winter pro” bee feed. I purchased the 50 lb tub. I was hoping to open the hive less and have the confidence of knowing that they would be well fed when I was absent for short periods of time.

    To my dismay, my two hives would rather starve to death than eat this product. At the end of January, I noticed massive amounts of bees dead on the bottom board. I opened the hive to see the honey stores gone and the massive amount of Winter-Pro still in the area close to the cluster untouched.

    When I was able to address the food problem, my hives were too weak to survive the remaining winter. I lost both.

    In speaking with another beekeeper friend who also tried it had the same result, lost all of his hives.

    I will go back to sugar water and leave more honey in storage in the future.

    • Harold,

      That is really sad, and I agree with you. Plain old sugar always works, the fancy additions sometimes don’t.

  • Then there’s the variability of grain size distribution and the imprecision of your typical strain gage kitchen scale. I’m thinking there’s probably a lot more important things to occupy your beekeeping brain besides nectar ratios.

  • I just fill a quart jar half full of sugar and finish filling it with hot water from the tap. I have even used a 2 liter bottle the same way. Haven’t killed my bees yet!

  • Rusty –

    Thanks for this article. It made me laugh and think about my father’s advice about arguing with people more stubborn than I am (he didn’t say stubborn….) – they will drag you down to their level then beat you with experience.

    I learned a similar lesson when working as a restaurant server. When a customer requested a “pat” of butter and then complained that it was not enough… After that, I thought it best to take them more than enough. A “pat” to me may be a 1/4 cup stick to someone else.

  • Wonderful article, Rusty. I rarely read one that doesn’t leave me with a smile (and a revelation). Thanks. Alan.

  • My feeding got much easier when I just use water from my hose for 1:1 and hot tap water for 2:1. Works great. Bees take it all.

  • Although I try to get close to a 1:1 or 2:1 ratio, I don’t very often. My girls don’t care. One thing that I have noted with them is this. After they finish off the syrup that I have placed in the outside feeders, once it rains and fills them back up (I use medium-sized dog bowls full of rocks and sticks for outside feeding), the bees are back on that water taking it up, and that liquid definitely is not any of the “defined” ratios. I think they are just liking the sugar water and that’s it. So I don’t get terribly worried about exact amounts. (Too much ADD to care).

  • I am in my 3rd year. The first year I agonized over, well, everything. My syrup Had To Be Perfect. In my second year, I tried harder to be more realistic. What worked, what didn’t. Learn and adjust. Now in my 3rd year, I fill the jar halfway with sugar and then the rest with water.

    Truthfully the moral of the story is bees have more problems to worry about. Our exact or not exact measurements of syrup are not going to kill them.

    Thanks for another great article.
    NW Georgia

  • For the woman who wanted to know how to “fix” the syrup after her husband swept up the leavings: since he added an estimated 1 tsp of sugar, she should add an estimated 1 tsp of water to restore her perfect ratio. Or not! as you carefully explain, again and again.

    Now, the fellow who reported calculating all the measuring utensils in the kitchen out to 7 digits of precision deserves to be beaned with a rolling pin. As we say in our household, the guy is probably a physicist, definitely not an engineer.

  • OMG. Thank you!. So many new beeks ask these type questions and I give the same answer as you in short. Now I have a reference to give them, except it’s so long I doubt they will read it, otherwise wouldn’t they have read about this and figured it out already? Maybe you have to be an engineer for a while like me and finally realize that all these hard ratios and formulas of perfection have imperfection at their root, they are guidelines themselves for getting us to results that work. There’s a little fudge factor in life itself? or actually more likely in our brains for thinking that there was some magic perfect formula at all… that perfection is actually possible… You should have told her to make sure to measure out and add 100 extra grains of sugar for the teaspoon with tweezers, maybe that would have got her over the hump?

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