Not a chemist but a biologist but had to read up on invert sugars lately.

 

Recently we had a problem with a supplier making batches of inverted sugar from sucrose for the first time without knowing what he was doing and without quality control. There was a high winter mortality among the people who used these batches (that is how we became aware of the problem). Lab results of these batches showed 20 to 40 times more HMF than "normal", above toxix threshold. We found out that he heated too long and used too much acid (citric). First the sucrose has to split into glucose/fructose and those 2 combined at higher temperature/low pH form HMF and other compounds (presence of metal ions increases HMF production). 
HMF will form in any acidic sucrose solution in the long run but both inverting and HMF formation are highly dependent on temperature. At room temperature the formation is really slow, it will take at least weeks to get to a toxic threshold. At 60 degr C it is a matter of hours. 

 

I normally lower the pH of my winterfeed to 5 with citron juice, I like to think it is more similar to honey and "less empty" and I have no strange winter mortality. I use sugar solutions wihtin 2 days or so.   

 

atb

Lennard

 

For those who want literature:

 

Bailey, L. (1966) The effect of acid-hydrolyzed sucrose on honeybees. Journal of Apicultural Research 5(3): 127-136
 
International Honey Commision of the World Network of Honey Science (1999) Harmonised Methods of the International Honey Commission; http://www.bee-hexagon.net/en/network.htm
 
Jachimowicz, T.; El Sheribiny G. (1975) Problematik der Verwendung von
Invertzucker für die Bienenfütterung. Apidology 6 (2): 121–143.
 
LeBlanc, B. W.; Eggleston, G; Sammataro, D;  Cornett, C; Dufault, R; Deeby, T; St. Cyr, E (2009) Formation of Hydroxymethylfurfural in Domestic High-Fructose Corn Syrup and Its Toxicity to the Honey Bee (Apis mellifera). Journal of Agricultural and Food Chemistry 57: 7369-7376
 
Von der Ohe, W; Dustmann J. H. (1999) Zusammensetzung von bienengerechtem Futterzucker (Zuckerteig und –sirup). Das Bieneninstitut Celle informiert (7): 1-3

 
 		 	   		  
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