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Every time I use my molds for chocolate bars, they bloom.

Every time I use my molds for chocolate bars, they bloom.  However, If I dont use the molds and pour the chocolate on parchment paper, the chocolate is perfectly tempered, shiny and has a beautiful snap. As soon as I put the same chocolate into a molds, it blooms in the center on the top of the chocolate while the outside edge looks tempered. 

This has now happened three times. the air temp is approx 64-68F, and the humidity has been about 40% with moderate air flow in the kitchen.  I am using thin theroformed molds from tomric that are unheated before I pour the chocolate into them. 

How can an unheated mold pull chocolate out of temper? 

Has anyone experienced this before?  I appreciate any advise or tips. 

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Try popping them in the fridge for about 15 minutes as soon as they start to show signs of crystallizing around the edges.


Thanks for the suggestion.  I actually did that with two of the batches and still had the same result as the others.

I don't think you have bloom. I think you have release marks from the thin molds.

There are two kinds of bloom. Sugar Bloom -Humidity on chocolate dissolves some sugar & then the syrup evaporates leaving sugar crystals on top. and Fat Bloom - The chocolate melts, some of the cocoa butter separates and comes to the surface, and leaves you with spots on your chocolate.


What you seem to be describing are white marks (possibly circular) on your chocolate right after you de-mold it. I believe this is from the chocolate pulling on the mold as it contracts and the mold not holding firm. - the result is something like scraping the surface of the chocolate. It just makes a smudge. I can't say this with certainty though as I'm still learning.

We don't do a lot of molding, but I experimented with reinforcing some thin business card style molds with epoxy. - (sand the back of the mold to get a rough surface for the epoxy to adhere to, then pour epoxy on the mold.) The reinforced molds did perform better than the non-reinforced molds, in that the release marks were reduced. However they were not eliminated. :( 

Kerry's idea about putting them in the fridge may do the trick. - It is certainly worth several attempts.


Thank you for your insights.I am having problems with the bloom on the top of the chocolate bar that does not touch the mold.  The outside edge seems to remain in temper, while everything else seems to come out.  When I break the bar apart the inside is whitish and chalky as well, while the outside edge retains its snap.


How thick is this bar you are making?

I have four sizes between 5mm and 14mm.

Ok - so that's probably not interfering.  See how it goes with Mark's heating suggestion and let us know.  

Good crystal information in Beckett - The Science of Chocolate - but that might be a little more complex than you want.  I think that Greweling covers it pretty well in Chocolates and Confections.

You mention that the room conditions are 64-68F.  If your moulds are this temperature it can be the problem.  When you are in temper, only a small percentage of the cocoa butter is crystallized in the type V crystals (~3%).  If you deposit the chocolate in a cool mould you can crystallize some of the fat on the surface in less stable crystal forms.  Ideally you want the moulds to be at or just below the temperature of your tempered chocolate.  The thin plastic moulds are notorious for this as they do not hold the heat.  Polycarbonate or thicker moulds are more insulated from losing their heat but they should still be warm when depositing.


Thank you so much for that information.  I will definitely try warming the molds first before I fill them. 

I would really like to expand my understanding of chocolate crystal formations.  Are there any resources your could recommend? 



Keep searching on this site, there are several discussions that talk about this. I faced these problems too up until the last week or two!

What I've learned about molding is:

  • Crystals give off heat as they grow. Chocolate becomes solid due to crystallization. In a mold, often heat has trouble escaping. That's why people tell you to refrigerate once you see clear signs crystallization has gotten off to a good start. Note that simply putting the full mold in a cold place / the fridge might not be enough for very thick pieces, since it'll just warm up the immediate area it's in. Some recommend putting a fan in your refrigerator :D
  • Cocoa butter left on the mold from the first batch of chocolate will stick to the next batch if you don't melt it by heating the mold up before pouring in the second batch. Obviously don't heat it too far above 30°C or the chocolate you pour in might go out of temper. I have a dish drier that runs at a constant ~50 degrees or so, so I put the one mold in there while I'm pouring another. I guess putting it under a lamp would also work. You just need enough heat for the cocoa butter to warm up so it can integrate into the next chocolate rather than stick on the surface and look nasty.

That is all extremely helpful.  Thank you.  With my next batch I will definitely experiment with warming the molds and using a fan. 

It depends on how deep you want to get into it.  There are several articles, youtube videos and such on crystal formation that keep it simple, covering the temperatures you use and a little bit on why.  For more depth there are several books, Beckett and Minifie are two good ones.  If you're just interested in the fats involved with confections then Talbot is good. 


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