Can I just let my chocolate stir at 88 F for a few days in my tempering machine to temper it?
As it turns out, I was going to do a follow up to Ask the Alchemist #77 about tempering, and specifically address this.
Basically, what you should get out of this is that the melting point of a crystal (94 F for Type V) is not really related to its formation speed at all, except the formation rate is zero at the melting point, i.e nothing can form if it is melting. All other bets are off.
To explicitly answer your question, the purpose of reducing your chocolate to 28C/80F is to create 1-2% Type V crystals ‘in a reasonable amount of time’. At this point I have had my tempering machine (alchemist built) run for 2 weeks. Lots of tests. LOT AND LOTS of failures….and some success.
The short answer is that 72 hours at 88 F- 90 F will not form Type V crystals. So I was slightly off base with my answer above. With that bit of lab data in hand I sent searching technical papers and confirmed that. It was not even that they were forming slowly. X-ray crystallography (pictures at crystal resolution) showed zero formation at up to 2 weeks at various temperatures.
Why? I don’t have all the answers yet, but I have a hint.
It has to do with folding structures. The best analogy I can come up with (representative drawings are actually coming) is origami.
You make lots and lots of folds to get to a final shape. It just isn’t possible to do from A to D. You have to fold the paper along line A. Then turn and fold along B. Then this little unfold along C and finally a last manipulation, and there is D.
Cocoa butter, being a polymorph, is the same way. And in this case, it appears Type IV crystals are one of the intermediate steps, so without IV, formed when you go down to 80-82 F, you can’t get to V directly.
I know that does not give any real practical answers, but I hope it starts to shed a little light on the process, and fills in just a few of the ‘whys’.
Stay tuned for more on tempering….I have had some interesting successes. Now to see if they can reproduced. Have a look.