After successfully building a power control system for my Corretto
roaster, my wife asked me if I could find a way to make chocolate
tempering easier for when she makes chocolate truffles. Of course I
had to try!

If you haven't seen it, you might wish to look at the long description of
pyRoast and the automated power control for a Corretto here:

http://coffeesnobs.com.au/YaBB.pl?num=1259627839

The problem with making chocolate truffles is the tempering of the
chocolate. To 'temper' chocolate you have to put it through a pretty
precise temperature profile. First you need to bring it up to 42C
to melt it, then slowly drop it down to 32C by adding in 'seed'
chocolate, which imparts the needed crystalline structure to the
chocolate.

If you are off by more than a degree or two then it doesn't work, and
you need to keep this narrow temperature range even while putting
very cold chocolate truffles from the fridge into the bowl.

The approach I took was to put two bowls (one inside another) on top
of a heat gun. The heat gun was then controlled by the same power
control device I use for my Corretto coffee roaster, which in turn
is controlled by pyRoast, my little python coffee roasting UI.

The outer bowl has a small amount of water in it (about 100ml or so)
as a buffer, and the thermocouple is taped to the inner bowl.

You can see the whole setup here:

 

You can also see a movie of the whole process here:

 http://samba.org/tridge/pyRoast/Chocolate/tempering.avi

the movie was taken towards the end of the truffle coating, so there
isn't much chocolate left in the bowl.

To support truffle making, I added a new 'target' control to pyRoast,
which allows me to easily adjust the target temperature while it is
running. You can see the new UI here:

 

As usual, the code for pyRoast is here:

 http://samba.org/tridge/pyRoast

Happy truffling!

Cheers, Tridge

truffle snob?

Forgive my ignorance, but I never knew truffles were such a hassle to make!

For very small batches I use the microwave method, works a treat.   Simply put about 80% of your callets in a plastic (not glass/ceramic) bowl and heat at 50% in 20 sec intervals, stirring well after each 20 secs.  Once it gets to the required temp (which varies a lot depending on type of chocolate, but 42 for 54% Callebaut works fine) add the other 20% and stir constantly until it's melted in.  If it won't melt after say 1 min stirring, then give it a 10 sec blast and continue stirring.

For larger batches I use my termpering machine (Rev1), but if I'm just tempering a little to coat somehting then the microwave method is great.

Tempering on a slab is way too hard for me - I've tried several times, with very mixed results.  I gave up on it when I saw a top pastry chef make a mess of it on Iron Chef - if he can make a mess of it, then it's too hard!

Cheers
Jonathon