Hi everyone,

I'm having an issue that appears in my polycarbonate moulds and I don't understand what's happening here.

As you can see on the pictures, the chocolate adheres on some small areas of the moulds, living an ugly look to the bar. I don't think it's a tempering problem, as 1/ I'm using a tempering machine that does the job perfectly, 2/ not all the bars of the same mould have this. 

Oh, my moulds are clean and dry before use. 

Have you encoutered the same issue ? What do you thing about this and how to fix it ?

Thanks

Dominique

Looks like a tempering issue to me. The bar in the photo shows some bloom. If the chocolate is well tempered, it could be the ambient temperature where the molds are kept while the chocolate cools. This can cause a loss of temper.

updated by @thomas-snuggs: 11/05/16 12:47:38

Thanks Thomas for your quick response.

I set the chocolate in the fridge. What is strange to me is that some are perfect and some have that issue. Could it be a matter of temp fluctuation in the fridge, for example if I open the door too often to get some new moulds in, or if there are too many warm moulds in the fridge ?

Dominique, 

The temper is probably off looking at the pictures,  but I suspect the root of the 'problem areas'  is seen in one of the pictures you attached.   These molds have a plastic ridge underneath to stiffen the mold.   This is resulting in the cooling rate of the 'sticky' section under the plastic ridge to not be the same as the other areas of the mold.  A fixed temp fridge is unfortunately a poor alternative to a cooling tunnel where the temperature is ramped down during the movement through the tunnel.   You may find leaving the mold in longer helps or not!

It's something that we have dealt with by selecting molds that don't have these sorts of plastic bars under them.  A real cooling set up (tunnel) may not be as problematic but an inexpensive solution is to avoid certain mold styles.  

Do you use sheet pans with the molds placed on them or just place filled molds directly on the wire racks in the Fridge?  That can also make a difference in cooling rate and cause uneven cooling spots.  

You need to determine the correct time to have the molds in the cool also......

Good Luck

Thanks for your reply Powell.

You're saying that the temper is off, and I would really like to know what helps you see that in the picture. I don't understand this tempering issue, as I'm using a Chocovision tempering machine. It seems to me that what could bring the chocolate out of temper is a part of the process that does not involve the machine.

What you're saying about the moulds and cooling is very interesting, thank you. I put the moulds directly on fridge shelves, which are glass shelves and not racks. But I feel this is more a cooling issue than a tempering one (even if I can of course be completely wrong!). 

How would you proceed to cool the chocolate ? Do you leave it for the whole process in the fridge ? Or do you let them cool at room temp (what temp?) after a specific time in the cold. What's the temp of your cooling device ?

Thanks a lot for helping me.

Dominique

[quote="dominique"]

Thanks for your reply Powell.

You're saying that the temper is off, and I would really like to know what helps you see that in the picture. I don't understand this tempering issue, as I'm using a Chocovision tempering machine. It seems to me that what could bring the chocolate out of temper is a part of the process that does not involve the machine.

What you're saying about the moulds and cooling is very interesting, thank you. I put the moulds directly on fridge shelves, which are glass shelves and not racks. But I feel this is more a cooling issue than a tempering one (even if I can of course be completely wrong!). 

How would you proceed to cool the chocolate ? Do you leave it for the whole process in the fridge ? Or do you let them cool at room temp (what temp?) after a specific time in the cold. What's the temp of your cooling device ?

Thanks a lot for helping me.

Dominique

Without detailed knowledge of what you are doing any 'free advice' is fairly worthless...

However,  the temper was checked how? Just 'cos your machine tells you it is 'ready' doesn't always mean the chocolate is in 'good temper'.  I can see some inclusions which are unmixed chocolate? which is why I  say that the temper may not be good?

If you read my first reply again, I am also saying it's in part a cooling issue.   If you are certain your chocolate is good temper, look at the molding and cooling  conditions.   Was the mold pre-warmed before filling? 

Glass shelves......The cool air of your fridge likely needs to be able to get to the bottom side of these molds to allow the latent heat of crystalization to be removed.   (That's what is being generated when chocolate is being moves from a 'liquid' to a 'more solid' form).     We use wire racks not sheet pans or glass shelves, my commercial set up also has fans in it.  With molds placed on sheet pans we have seen areas of molds cool at different rates.  The chocolate needs to stay in the cool long enough for it to set to the point it is starting to come away from the mold.   Just look at the underside and compare an uncooled mold with one that's spent time in the fridge. 

You just need to figure out a set of conditions that work for the chocolate you have and the equipment you are using... Again, experimentation is the answer not somewhat random advice off the internet... (:-)

Just remelt your 'failures' and try until you get it right.....

Hi Dominique,

Here's a link to my setup at home when I cool my chocolate bars. I use some small racks that will hold six molds. I've also put this rack in my refrigerator if it's too hot to let the bars cool on the counter. I thought this might help.

http://chocolatetalk.proboards.com/thread/1733/small-scale-cooling-racks-chocolate

-Thomas

[quote="Thomas Snuggs"]

Hi Dominique,

Here's a link to my setup at home when I cool my chocolate bars. I use some small racks that will hold six molds. I've also put this rack in my refrigerator if it's too hot to let the bars cool on the counter. I thought this might help.

http://chocolatetalk.proboards.com/thread/1733/small-scale-cooling-racks-chocolate

-Thomas

Hi Thomas.....

Betty Crocker is your friend! Good find.... Looks like a handy small scale set up, guess it depends on how warm the room is and the time you have...  We are currently making 200+ bars an hour, next on my wish list,  a vertical cooling tunnel like the one FBM offer.

Thanks Thomas, indeed the picture of your set up is helpfull. I like the rack you're using, and keep this idea for when I'll make bigger batches. Nice also to see your fan installation.

Actually I've fixed the issue, which was multifactored. I started by checking the temper even in the machine, and 2 times out of 6 the machine was saying tempered although it was not.

Then I set my moulds 10mn in the fridge and let them finish the cooling on shelves at room temp. They were perfect.

I think aside the tempering issue, the problem was due to too much mass in the fridge at the same, resulting in bad air fluctuation.

Thanks for you help, that's great to get support from more experienced people.

Dominique