I molded chocolates today (using 2 different types of molds) and had the same problem -- a super fine separation between the top (what I call the cap) and bottom layers of chocolate.To mold the chocolates, I coated the mold once, let it rest in a cold room, coated the mold again, let it rest agan, filled the chocolates (one a ganache, the other a mousse), and then closed the mold with a layer of chocolate. Cutting into a chocolate, the thickness was consistent around the filling. Also, I use a professional melting and tempering machine. There were no other problems with the chocolates.This is the first time I've seen this issue. Any ideas? Thanks so much!
updated by @jennifer-thamer: 04/18/15 04:20:00

This doesn't answer why you have the problem but may help fix it. You can try taking a blow dryer or heat gun and quickly, very quickly, blow it over your mold. If you blow too hot, too long you will throw the temper off the whole thing so be careful. This helps the top and the bottom to bond together and may fix your problem.

JWhy are you shell moulding twice? For moulded pralines this process usually only needs to be done once. Thin is in! But if you have to mould twice, don't go to the cold room between mouldings. It sounds like you are getting nearly complete crystillization on the first layer before you add the second dosing of chocolate.brian

Thanks, Sara and Brian. It sounds like temperature may be the issue.I agree with you Brian on thin layers, but if I don't mold the chocolates twice, they "explode" (e.g., crack on top) a few days later...Would I be able to see the crystallization on the first layer? I think you may be correct about the cold room, but it hasn't been a problem in the past and I've followed the same steps every day for months. Thank you!

Hi Jennifer,Got a couple of suggestions to make the shell thicker with just 1 coating, let it stay in the mould a little longer before tapping out.It can also be in your fillings. Some fillings, if you let it crystallize in a chiller contracts more rather than working room temp. It has a tendency to expand again when it gets to regular room temp (same as chocolate display chiller) so the shells explode. So try just letting it crystallize at working room temp before putting in the bottom covers.The thin line around the bottom can also be prevented by running a heat gun over the moulds just before capping them. So they attach better since they are almost same temp as the melted choco you are pouring.Also one chef I trained with said, not to use tempered choco on the bottom covers because tempered choco contracts and can "pull" on the sides.Hope this helps. Happy choco making

Thank you -- your advice is really helpful! I'll try it out this week.

Hello, I wanted to follow up... We are using the cold room less to keep the chocolate at a more consistent temperature before closing the molds. We're also careful not to get filling on the sides of the chocolates before closing -- that oil may have been part of the problem, even if the sides are wiped clean. The good news is that since we made the changes, there haven't been any issues. Thanks again for your helpful replies!