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 mailto:[log in to unmask] --