Molding Chocolate
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Tech Help, Tips, Tricks, Techniques
John,I fear that my following post comes across as me lecturing, which is not my intent in the least. I know that you are as versed in chocolate tempering physics as I am, and perhaps more so. The lengthy diatribe is for Lemm's sake, and is hopefully helpful to him. There are some parts that are relevant to what you typed above, however, so I am "replying" to you.Begin:Right, as Wybauw says, extreme cooling--either too cold or for too long--will lead to unstable crystal types and, therefore, bloom, but Wybauw also recommends cooling molded chocolate at temperatures approaching 40 F and with large volumes of air--not an exact quote. I'm not recommending extreme cooling, and I don't think that Lemm would necessarily need temperatures approaching 40 F. This is especially the case since Wybauw is talking about a production environment where there would likely be a lot of thermal mass in chocolate and molds that would have to be cooled at once, and Lemm is probably only dealing with a few molds.It still sounds to me like this is a cooling issue based upon Lemm's following comments:1) it snaps and looks good when spread on a thin piece of wax paper--probably in contact with the top of a counter, which would cool it more effectively through direct contact. Molds keep chocolate up off of additional solid objects like counters and one must depend upon the convection of the air to do the cooling.2) it has bloom issues when molded, and more issues against the mold than the part exposed to the air.3) House temperature is 72 F, which is relatively warm.4) Lemm said that cooling the molded bars in the fridge get's rid of the bloomI could be wrong, and certainly trying to diagnose without seeing things is tricky at best, but I feel that Lemm is not removing enough of the latent heat of crystallization quickly enough in the thicker molded pieces, and this is compounded by the insulating properties of the molds, the relatively warm 72F room temp, and likely the lack of air flow, leading to bloom on the surface and back of the bars.The idea of moisture forming on the mold prior to pouring the chocolate, as Lemm suggested in an earlier post, seems to be contradicted by Lemm's comment that the bloom doesn't happen when the molds are pre-cooled. If it was moisture on the mold due to high relative humidity that was causing sugar bloom, then I would expect the problem to be worse with mold pre-cooling, not better. I agree with John that pre-cooling molds is not a good idea.Lemm, you mentioned "thin plastic molds." Do you have the injection molds--not too flexible, or the thermoform molds--pretty flexible? They both will insulate, but the injection molds insulate quite a bit more.Anyway, you'd be surprised how very small things that you'd think shouldn't matter can impact molded chocolate.Alan
