Jean-Louis Tu wrote:

> Does someone know details about heating of honey, namely:
>
>  -what is the temperature, and the processing time?

Variable, as the heating is not a standardized industrial operation, but
is often done at the producer's level. Every producer or distributor has
his own method which varies. The temperature is around 50 to 100°C,
sometimes done by immersion in a pan of boiling water ("au bain-marie"
in french). The duration is usually intended to "melt" the honey if it
was cristallized. The duration is somewhere in the area of 3 to 20
minutes. A minimum time is necessary for the heat to melt even the honey
in the core of the jar (proof that it affects the whole content).
Heating the honey generates a small proportion of HMF molecules known to
be highly toxic. In Europe, a study has shown that more than 80% of the
honey in the standard commerce has HMF-levels above the authorized
standards for public health.

>  -how can I recognize a heated honey from a raw honey?

Very difficult. The taste changes slightly in a "caramel" direction, but
this is very difficult to identify if you don't have the same original
unheated honey to compare, because of the very wide variety of tastes of
natural honey.
The only sure way is to know how the honey was produced. Find reliable
producers and question them. Producers know what they do and can be
questioned. Distributors and retailers never know what happened to the
honey they sell before it gets on their shelves. They will always tell
you it's OK and "best quality", but it most cases (even with some
organic honey) it isn't true. Often they're not dishonest, it's just
that they don't know themselves.

>  -can the taste-change be efficient with heated honey? I have tried so far
> at least 10 different honeys, and each time the instinctive stop
> came roughly after the same quantity (about 4 oz). Does it mean all
> these honeys were raw?

No. The taste change sometimes works more or less with slightly
denatured food in the same way as moderately heated grains will still
germinate. But if heated above natural temperatures, abnormal molecules
can be there at non-negligeable levels even if the stop occurs.

If there isn't any stop at all, hovever, you can be sure there's a
problem.

Rawest and instinctive salutations.

Bruno.