I have a very strange problem that I am hoping for insight on.  I pan inca berries (physalis peruviana) - (and a lot of other products too).  However when I pan the inca berries a white(ish) powder forms on the surface of the product as it tumbles.  It can become very thick - a coating of dust that is difficult to remove.  Further, if I leave the coated berries resting overnight the dust multiplies. 

This does NOT happen with any other product - coffee beans, cherries etc with the same chocolate.

I usually use Sicao 53% (a Callebaut brand out of Singapore - very good couverture chocolate).

I believe that the issue is created by the fact that I have to pan for a long time - sometimes hours - and I think that it might have to do with micro-movement of the chocolate as the berries contract and expand as they tumble in the pan.

The reason that I need to pan for so long is that the berries have deep crevasses and I need to fill them in by running the pan and also heating the chocolate to melt it, let it harden and then melt it again repeatedly.  I believe that during this process the chocolate tembers, looses tember and re-tempers multiple times. 

I suspect that it has something to do with crystalization or probably over crystalization and maybe something to do with the coca butter.  But I really am bamboozled.

I'd like to know what it all is with a view to being able to avoid it developing. But it way past my modest skill set!

Does anyone have any thoughts on this please?  Thanks!

if you're reheating during panning, it's definitely coming out of temper but not RE-tempering correctly when it cools.

I'm not familiar with the viscosity level of that particular chocolate. But a less viscous couverture may get into the crevasses during the panning process.

I've had better success when panning by using 2 or 3 coatings... but first coat is done with UN-TEMPERED chocolate, which will be much more fluid (get into the crevasses). It usually takes longer to set up, but once it is, you can do a second coat with TEMPERED chocolate. 

Thanks for that. With panning we do indeed use untempered chocolate.  With deeply crevassed products such as inca berries the chocolate fills the voids but it also coats the "peaks".  As far as I can ascertain, the tumbling tempers the chocolate on the peaks but not the chocolate  in the voids so the untempered chocolate is thrown out of the voids making the voids ever larger as the (tempered chocolate) peaks build up.  In the five years I have been doing panning I have learned "mostly" how to work with this (a story in itself). This has been a real journey for me as seemingly very few people pan any more and those that do seem to stick to easier products such as coffee beans, nuts etc.  The inca berries are the very worst to work with.  But then it gives me some pretty "clear air" as most others don't try.

This "powder" is an ongoing problem and I'm hoping that someone that understands the chemistry of chocolate can shed some light.  The "dust" can become quite thick - to the extent that when I try to blow it off with compressed air it gets everywhere in my panning room and if I try to add gum arabic to it, it simply soaks up the gum arabic making for a really bad surface.  I AM making some progress but my "fixes" are mechanical - I'd like to know what this dust is and what is really making it form.  And then, hopefully, how to prevent it.

Thanks!