The syrup we feed bees in the fall is generally in the ratio of 2 parts sugar to 1 part water, either by weight or volume. That means the mixture is about 66% sugar and 34% water. But before the bees cap syrup (or honey) they dry it to roughly 17-18% water. Using round numbers, let’s call that 20%.
Now a solution of 80% sugar to 20% water is in the ratio of 4 to 1. So if you were making syrup this thick, you would have to put twice as much sugar into the water as you do for 2 to 1 syrup. That is really hard to do.
And remember we rounded up to 20%. If we wanted 18% moisture we would need 4.56 parts sugar to 1 part water, or 4.56 pounds of sugar to 1 pound of water. The 17% number requires 4.88 pounds of sugar to 1 pound of water—dangerously close to 5:1. As you can see, capped syrup (or honey) has very little water in it.
So the bees take their 2:1 syrup, store it in cells, and fan like crazy to drive off the extra water, of which there is a lot. Trouble is, as the ambient temperature gets colder in the fall, it becomes harder and harder to drive the water from the syrup. Not only is the liquid colder, but the cold air surrounding it can’t hold as much moisture as the warm air of summer. Add to that there are fewer bees doing the work. Everything slows down and capping takes forever if it happens at all.
Eventually, when the syrup itself reaches about 50° F (10° C), the bees give up and the syrup sits unattended in the feeder. You simply cannot feed liquid syrup to bees once the temperature of the syrup dips too low, which is why beekeepers use candy boards, fondant, or dry sugar for colonies that need a feed supplement in winter.
Rusty
I’ve been feeding honey back to most of my hives instead of syrup. I learned from a Brushy Mountain video that the bees can convert 1 gallon (almost 4 litres) of thick syrup into a pound of stored syrup or fake honey.
One of my hives took down six pounds of uncapped honey in about two days, or the equivalent of 23 litres of syrup.
I know the bees still have to cap it, but if most of the raw honey I’ve fed them becomes stored honey without any extra work to evaporate it down to 17% water, feeding them honey seems much easier than mixing syrup and filling feeders, etc. And less work for the bees.
Am I wrong about any of this?
I’m tempted to empty a couple jars of honey for them to save them the trouble of evaporating sugar syrup.
Phillip,
It’s always best to feed honey, if you have it. But that’s just the problem–we often have no honey of known origin, so we are stuck with feeding syrup. I always feed honey if I have the option.