New honey contains 1 to 5 mg/kg HMF.
In Holland, it is forbidden to sell honey with more than 40 mg/kg HMF.
When honey is being stored at 20 C (68F)  the HMF content will raise ±1 mg/kg per month.
Only fructose will become HMF. So the rise dependent on the kind of honey!!
Heating the honey will raise HMF contents rapidly. The longer and/or hotter it is heated,
the higher the HMF will become.

Table of the time to produce 30 ppm HMF
   temperature                           time in  day's
   30 °C        80 °F                   150-250
   40 °C        110 °F          20-50
   50 °C        135 °F          4.5-9
   60 °C        160 °F          1- 2,5
   70 °C        185 °F          5 -14  houre
From Belgium (VIB) honeybook (1990??)

what heat (and microwave) do with enzyme, see:
htp://www.xs4all.nl/~jtemp/EnzThem.html


regards, jan




 Larry Krengel wrote:
> One aspect of heating honey that I don't
> recall having discussed is the effect of the length of time held at an elevated
> temperature.  With my freezer-warmer, it is ease to hold the temperature constant
> for as long as I want.



--
the orginal drone methode, fight the varroa chemistry free
Jan Tempelman
Kerkstraat 53     NL 7471 AG Goor
xx.31.(0)547.275788
http://www.xs4all.nl/~jtemp/index3.html
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