Friday, May 29, 2009

Sugar Water for Bees

This discussion gets into a bit of chemistry, hubby's profession, as well as beekeeping. At one of the last Beekeeper meetings someone said, "If there are 10 beekeepers in the room, there will be 20 opinions!" Probably true!

One of the very experienced beekeepers asked Hubby about sugar water and these are the emails:

We beekeepers have been having a "heated" discussion about sugar syrup to feed to bees. When I make bee juice, I bring the water up to a boil, then add the sugar, stir, then return to a boil. I am under the impression that the continued boiling actually inverts some of the sucrose into glucose and fructose, making the resulting simple syrup sweeter.

The counter side to that is continuing to boil the solution will result in carmelization. I think that this is incorrect, as long as there is water present, the temperature can not raise above boiling and carmelization does not occur until 320F. Is my logic incorrect, or am I missing something?


Invert sugar is easy to make, just as you suspected. Boiling accelerates this process,but it continues even at room temp. Carmel color will not hurt the bees, but there is very little nutritional value left. As you know, the temp does not rise much until most of the water is gone, so I would not boil more than 15 min or so to achieve the desired result.

So, there really is no carmelization at the boiling point of water. I would have to boil a 1:1 solution for a rather long period to get carmelization. I've also been told that the addition of glucose helps prevent the sucrose from recrystallizing.

The addition of glucose would in fact inhibit crystallization, just like any impurity. Boiling point elevation and freezing point depression are related issues and the central fact is that when any "impurity" is added to a solution it will change the physical properties. This is the short version of a fairly complex subject in chemical thermodynamics, but you do not need the long version (at least not yet). Corn syrup would also change the crystallization properties, so inverting sucrose is the easiest way to add glucose and modify the physical properties. Acid will increase the rate of inversion much more than heat, so adding 1 gram of lemon juice or citric acid would accomplish nearly complete inversion in about 20 minutes of boiling.

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