The domestication of honey bees has directly resulted from their ability to produce abundant provisions to maintain the colony through periods of dearth. A colony will store honey in quantity to survive for times of little or no nectar flow. This excess honey has for millennia been a prized food source for us! As our harvesting of honey could leave the bees starving during the winter, we have a responsibility to replace what we have taken. This is, for the most part, done through the feeding of sugar syrup back to the bees. So as beekeepers, we want to provide the best feed possible to our bees. There are some considerations to ensure the quality of syrup and feed which will be discussed in this, and next, week’s blog.
Feed Quality - Part 1
Fall feeding of bees should be done with heavy (67% sucrose)
syrup. The syrup should be the highest
quality and most fresh available.
Sucrose, the white granulated sugar that is found in most kitchens, is
preferred and what most beekeepers in the Atlantic region use. Other sugars such as high fructose corn syrup
(HFCS) can be fed to honey bees if it is high quality but nutritionally,
sucrose is better for honey bees.
For most beekeepers there are two options for sugar
syrup. Granulated sucrose can be
dissolved in water for homemade sugar syrup or premixed sugar syrup can be
purchased. Both options have
considerations when it comes to quality.
Homemade syrup is fine as long as it is made carefully. The saturation point for sugar in solution is
67% sucrose at room temperature (20˚C).
If the temperature of the solution is increased, dissolving the sugar is
easier but excessive temperature can create compounds which are toxic to
bees. So, care must be taken to avoid
overheating the solution. Boiling of
syrup must be avoided! If purchasing
premixed sugar solution, it should be fresh and checked for any indication of
degradation.
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| Filling a frame feeder with sucrose syrup (ATTTA 2024) |
There are simple ways for beekeepers to check the quality of sugar syrup. Sugar syrup should be clear with very little colour. As feed ages other compounds form from the sucrose “browning” which occurs. This colour change is due initially to the formation of hydroxymethylfurfural (HMF)1. This is a compound toxic to bees and linked to mortality2. Fresh, high quality sugar syrup should have no unpleasant smells. Any off smell could indicate fermentation or other degradation. Sugar syrup should not be frothy or produce any gasses. This is also an indication that the syrup is degrading.
There are other tests which can be conducted to determine
the quality of sugar syrup. If the basic
assessments mentioned above throw up any red flags, this is a very good option
for beekeepers. The acidity of the feed,
as indicated by pH, is a very good quality measure. Fresh sugar syrup should have a pH around 6.0
to 7.0. For context, milk is about 6.5 and pure distilled water is completely
neutral at 7.0. As the sucrose breaks
down, acids are formed and these lower the pH.
Some of these acids are toxic to bees and will reduce their longevity3. Another important test of sugar syrup is titratable
acidity which measures the total acidity of the solution. This is different from pH and is an
indication of how difficult it is for the bees to utilize this feed. When the bees consume syrup which has high
total acidity, they are required to buffer it in their gut for digestion. So titratable acidy shows how hard the bee’s
gut need to work to buffer against the acidity present. It is also worth noting that two syrups with
the same pH may have different titratable acidity. Another measure of syrup is Brix (˚Bx) which
is, in this context, a measure of the amount of sugar in the solution. Sugar syrup for fall feeding should be 2
parts sucrose to 1 part water by weight.
This would mean that there are 67 grams of sugar for every 100 mls of
solution with a ˚Bx of 67. These lab-based tests can be arranged by
sending a sample to ATTTA.
Next week we will continue to discuss feed quality!
Connecting with ATTTA Specialists