Can Tempered Chocolate Lose its Temper in the Process of Cooling?

[wannabechocolatier]

Would, say, pouring a thick slab of properly tempered chocolate encounter any issues without the assistance of a fridge? Or would it all eventually set properly given that the ambient temperature isn't in the 80s or higher?

[Jonathan]

Thick slabs won’t cool evenly and you’ll get streaks even if it was tempered properly, if you want to store it just spread it out a little

[wannabechocolatier]

2 hours ago, Jonathan said:

Thick slabs won’t cool evenly and you’ll get streaks even if it was tempered properly, if you want to store it just spread it out a little

Thanky

[Jim D.]

I have long had a question that is related to the topic of this thread.  In tempering, once all the crystals are melted, tempered seed is added (or formed from scratch if hand-tempering) so as to "encourage" Type V crystals to form.  The theory is that more and more of them will form, and the chocolate will be "in temper."  If I understand the theory correctly, if the chocolate is allowed to cool, the undesirable crystals (I-IV) would ordinarily form, but because there are so many Type V, the others cannot.  If this is true, then why (as @wannabechocolatierdescribed) does a poured slab often show obvious signs of not being in temper?  Is it the "latent heat of crystallization" that throws the slab out of temper (too thick for the heat to escape), or do Types I-IV somehow manage to form?  When I empty out a large bowl of leftover tempered chocolate onto parchment to be saved for another batch, I encounter various outcomes:  Sometimes, when the slab is not so thick, the chocolate seems to be perfectly in temper (shiny, no streaks, plenty of snap).  Other times the slab becomes bendable, off-color--obviously out of temper.  At still other times the slab has a swirly, marble-like pattern but might still have some snap.  On the other hand, some manufacturers sell fairly thick bars of chocolate (I often use these as seed), and they are presumably in temper.  How do they manage that?  Are we in a theoretical, Mark Heim-like area of expertise here?  Any ideas?

[wannabechocolatier]

@Jim D. My guess is that type V crystals don't propagate as quickly as we've been led to believe. If that's the case, then if a large block is cooling and there's a section with no adjacent type V crystals and that section is cooled sufficiently before it's reached, it'll set untempered.

 

Maybe manufacturers keep their chocolate at the proper temperature for long enough so that the crystals fully propagate. They also probably have the means to agitate their mixtures really well, so that type V crystals are constantly contacting uncrystallized areas and propagating. 

 

That's my theory, anyway, not sure what else it could be.

[Kerry Beal]

2 hours ago, Jim D. said:

I have long had a question that is related to the topic of this thread.  In tempering, once all the crystals are melted, tempered seed is added (or formed from scratch if hand-tempering) so as to "encourage" Type V crystals to form.  The theory is that more and more of them will form, and the chocolate will be "in temper."  If I understand the theory correctly, if the chocolate is allowed to cool, the undesirable crystals (I-IV) would ordinarily form, but because there are so many Type V, the others cannot.  If this is true, then why (as @wannabechocolatierdescribed) does a poured slab often show obvious signs of not being in temper?  Is it the "latent heat of crystallization" that throws the slab out of temper (too thick for the heat to escape), or do Types I-IV somehow manage to form?  When I empty out a large bowl of leftover tempered chocolate onto parchment to be saved for another batch, I encounter various outcomes:  Sometimes, when the slab is not so thick, the chocolate seems to be perfectly in temper (shiny, no streaks, plenty of snap).  Other times the slab becomes bendable, off-color--obviously out of temper.  At still other times the slab has a swirly, marble-like pattern but might still have some snap.  On the other hand, some manufacturers sell fairly thick bars of chocolate (I often use these as seed), and they are presumably in temper.  How do they manage that?  Are we in a theoretical, Mark Heim-like area of expertise here?  Any ideas?

It is indeed the latent heat - I can make this effect happen by encouraging the latent heat to stay around - so what happens is the form V crystals get melted out in the heat.

 

 

[pastrygirl]

4 hours ago, Jim D. said:

On the other hand, some manufacturers sell fairly thick bars of chocolate (I often use these as seed), and they are presumably in temper.  How do they manage that? 

 

Cooling tunnels

https://www.sollich.com/en/products-en/chocolate-processing-en/cooling-tunnels-en