Sugar For Bees

By: Ann Harman

To feed or not to feed… (My apologies to Will S.) We want our honey bees to survive and live a good life but at times they are in peril from weather conditions. Prolonged drought, incessant rains, too cold or too hot at the wrong time all can make nectar scarce. Grass fires and forest fires can decimate square miles of possible forage. Winter, long and severe, keeps the bees within their nest but they still must eat to stay alive. So to keep colonies alive until conditions improve many beekeepers will want to feed their bees. 

The energy requirements of a colony depend on the carbohydrate supply – honey. But if incoming nectar is scarce it will have to be replaced with a suitable food. Nectar contains sucrose along with the small amounts of the color and flavor ingredients supplied by the particular plant. Other simple and complex sugars are found but in very small amounts. 

Green plants all make sucrose as a result of photosynthesis and other cycles (remember that from high school biology?). The chlorophyll and sunshine combine the atmosphere’s carbon dioxide and water to form glucose, followed by other cycles to form sucrose and some fructose.

Sucrose, a disaccharide, is the main sugar transported throughout green plants. You may be familiar with maple syrup obtained from the sap of the maple tree. It is water and sucrose with color and flavor compounds characteristic of maple trees. 

We call sucrose ‘table sugar’ or ‘white granulated sugar.’ Our table sugar is from the sap or juice of sugar cane or sugar beet. More about those later.

Sucrose, as such, cannot be used by honey bees or humans or even by cows or horses. The sucrose molecule must be broken into the two simple sugars of glucose and fructose. This is done by an enzyme called sucrase. In older books you will see it called invertase but today that word is reserved for plants. Sucrase is for animals (yes, that includes bees and humans).

The enzyme, sucrase, in bees is found in the stomach (ventriculus) where digestion takes place. Sucrase is also found in the hypopharyngeal glands of foraging bees. It may also be in salivary glands. So the process of converting sucrose to the two simple sugars in honey, glucose and fructose, is started by the foraging bees.

Glucose is an important sugar. The brain cannot function without glucose. It also supplies energy to muscles. Glucose also aids functions in body cells. What about fructose? It supplies energy but the brain does not use it. In humans fructose is actually metabolized by the liver.  

Fructose, although an important sugar, can cause a problem. In order to understand that problem, we need to meet hydroxymethylfurfural. That’s a ferocious chemical name, so it is called HMF. This substance is toxic to honey bees. Actually it is not good for humans either. 

HMF is formed from fructose. Heating fructose causes it to form HMF. Acids, such as vinegar (acetic acid), lemon juice (citric acid) and ‘cream of tartar’ (tartaric acid), when added to fructose will produce HMF. Our own foods, such as fresh vegetables (green plants) do contain a very small amount of fructose. When these are cooked HMF, in minute quantities, is formed. However, the level in our cooked vegetables is not dangerous. 

Several types of sugars are sold for bee feed: 

  • Invert sugar, a mixture of glucose and fructose, used by bakeries
  • Drivert®, very fine crystals of sucrose plus 8% fructose
  • High Fructose Corn Syrup, HFCS
  • Sucrose, table sugar

Let’s see how some of these sugars are made. Invert sugar, used by commercial bakeries, is made by one of two processes: by acid hydrolysis that produces HMF and enzymatically that does not. Unfortunately there is no way to know which process was used when buying invert sugar.

Beekeepers make invert sugar, called fondant, by boiling a solution of sucrose and water. Recipes are given for this in many beekeeping books. Unfortunately the recipes call for the addition of an acid, lemon juice or cream of tartar. The temperature for proper consistency of this cooked fondant must reach 238°F (115°C). The addition of the acid plus the high temperature causes HMF to form. An uncooked fondant can be made by just mixing sugar with high fructose corn syrup. However, HFCS can contain HMF.

Tanks of High Fructose Corn Syrup.

High fructose corn syrup is indeed made from corn by a rather complicated process. Beekeepers usually use HFCS 55 that means 55% is fructose, 42% is glucose. As manufactured, HFCS does not contain HMF. The syrup leaves the factory in large metal tanker trucks. HMF will begin to form at about 113°F (45°C). The tanks full of HFCS out on the highways during hot summertime mean that the contents could easily reach that temperature and higher. Furthermore the syrup will be distributed to retailers who may place it into metal drums for dispensing or sale. If these drums are stored in the hot sun, even more HMF will form. The higher the temperature, the more HMF is formed. The longer exposed to higher temperatures, the more HMF. It is impossible for anyone to know what the content of HMF is in any particular batch of the syrup. Chemical analysis is not economical.

What about honey – the bees’ natural food? Honey does contain fructose. So honey as stored in the hive by the bees will not contain HMF. However, repeated heating or too high a temperature will produce HMF. Honey, if kept at room temperature for a very long time will contain very small amounts of HMF, not toxic levels. If honey is scorched in processing by the beekeeper it certainly could contain a larger quantity of HMF. Therefore scorched honey may not be the best choice of food for bees. Honey does supply the bees with nutrients such as some vitamins and minerals, but in small quantities. It does leave residues in the gut that must be eliminated. 

Honey does have a problem that many beekeepers realize. It can contain the spores of American foulbrood (AFB). Any jar of honey from a supermarket can contain those spores, ready to infect a healthy colony. (Fortunately we, as humans, do not get AFB.) A beekeeper must know the health of the colony supplying the honey. Otherwise that honey could be a quiet fatal dose of food.

Is there anything else that bees could be fed? Let’s take a trip to the supermarket, and even the internet. Wow! There is a huge selection of sweet stuff! There’s Karo® light and dark corn syrup, molasses, agave syrup, sweet potato syrup, maple syrup, pancake syrups, fruit syrups. Then we see the selection of sugars: brown sugar, light brown sugar, demarara sugar, organic sugar or organic evaporated cane juice (might look a bit brownish), turbinado, palm sugar, powdered sugar (contains 3% cornstarch to prevent caking). And then we see the artificial sweeteners like Stevia and Aspartane.

Are any of those usable for bee feed? NO! Positively not! The crystal sugars have molasses giving the sucrose a bit of color and flavor. Molasses is toxic to bees as are the artificial sweeteners. Although we can eat these sweeteners without problems, the bees cannot. The Karo® light corn syrup contains vanilla and salt making it unsuitable for bee food. Dark syrups can have molasses as well as other coloring and flavoring substances. The bee’s simple digestive system can process the sucrose from plant nectar. The very small amounts of color and flavor compounds in nectar are not in toxic quantities.

So what is the best carbohydrate to give our bees when they are short of incoming nectar or have insufficient stored honey?

SUCROSE. White granulated sugar, table sugar. It is actually the purest, cleanest food in your home! It is exactly one substance – sucrose. It is completely digested by the honey bee, leaving no residue in the gut. Therefore in cold climates when bees cannot take cleansing flights easily or often, there is no buildup of residues in the gut. Sucrose is stable; it does not decompose. Kept dry it will last for countless years.

As mentioned earlier our table sugar, sucrose, is obtained from sugar cane and from sugar beets. The sugar from each is identical – both are 99.95% sucrose. The 0.05% difference is from processing, from using different clarifying agents. However these are not toxic to bees or humans. They are perfectly safe, ordinary inorganic compounds.

I can hear someone yelling – WAIT A MINUTE! Sugar beets are GMO! That has nothing to do with the sucrose molecule. GMO affects proteins in a plant. Sucrose is not a protein. The sucrose molecule is not affected by any genetic rearrangement – it would not be sucrose if it were affected.   

Sugar syrup, a liquid, is suitable except in the cold of Winter when the bees are clustered. They cannot remove the water from the syrup very well. There is one easy way to feed sucrose as a solid if mid-Winter feeding is necessary. This recipe is quick and easy, and makes use of the metabolic water from the bees to make the sucrose available.

10 pounds of white granulated sugar

8 ounces (one measuring cup) of water

Mix well – you now have ‘wet sugar.’

Make slabs on wax paper or plastic wrap to fit under the inner cover. Let them sit at room temperature overnight. In the morning they will be as hard as a brick. Peel off plastic wrap before putting on top bars. 

A well-fed bee is a happy, hard-working bee. Understand your climate and keep an eye on your weather. Feed if necessary. Your bees will appreciate that attention.

Ann Harman


Ann Harman lives, keeps her bees and writes for Bee Culture at her home in Flint Hill, Virginia.