Molding Chocolate

I've already posted this question on the Homebrew Group, but without a response so far. I'm posting it here in hopes that I will get some feedback.I am still getting fat bloom even after tempering the chocolate. I've tried molding at different temperatures (86 F to 89 F for dark chocolate) and two different methods (lowering temperature of whole batch to 82 F then up to 86F-89F versus taking about 1/3 to 1/2 of batch to cool and seed first then mix with rest), and I do it quite slowly to allow time for the beta V crystals to form.The bloom appears most heavily on the underside of the mold (where the chocolate touches the plastic). Minor blooming occurs on the chocolate exposed to the air.I don't get this problem when the batch is poured unto wax or parchment paper, when the molds are pre-cooled or when lecithin is used.The tempering does work from the standpoint of melting times. I did blind tests with my family to confirm this.I thought about this long, but cannot figure out why? Has anyone experienced this? Is their a solution?Here's more info.- The temperature of the house is around 72 F, very low humidity, winter here in Canada.- Using organic unsweetened chocolate, cocoa powder, cocoa butter from fermented, unroasted cocoa beans.- Using powdered sugar.- No emulsifiers used.- Using tiny batches of 100 grams or less for experimentation.- Use a heating pad and a digital candy thermometer which has been tested for accuracy.- I control the rate of the temperature rising by lifting on and off the heating pad, a glass cup containing the tiny batch of chocolate.
updated by @lemm-huang: 04/09/15 03:07:54PM

You need to cool the chocolate more quickly after molding. That will likely solve your problem.

I had the same experience until I accidentally left some molds under an air conditioner. It worked perfectly. I've found 60 F and a fan works very nicely.

I agree with Alan, I had a similar problem but just putting the filled molds in the fridge for 5 mins works a treat each time. Carefull not to leave in the fridge too long as it will condense water on the surface in humid places. Fortunately where I live is dry as a bone.

Thanks for all your responses.As I mentioned, I don't get this problem when I pre-cool the molds in the fridge and then I leave the chocolate to harden at room temperature.What I still don't understand is why I did not get bloom when I poured it on parchment or wax paper leaving it to cool at room temperature?I had a thought recently that the chocolate mixture cools down in the molds, and minute traces of moisture forms from condensation but is trapped by the chocolate mixture itself - this extra trapped humidity causing the bloom. That's probably why I don't get it with wax and parchment paper. Perhaps the plastic mold keeps the mixture warm longer than the more exposed mixture on wax or parchment paper. Heck, I don't know....Another question that could be related: How do you tell the difference between cocoa butter bloom and sugar bloom?

I don't think "pre-cooling" the molds is a good idea for lots of reasons.Fat bloom is more cloudy and diffuse; sugar bloom you will see white specs form.

I think your room is too warm. does this happen when you put the filled molds in the fridge to cool?If the chocolate when spread thinly on wax paper dries shiny & snappy and it feels cool to your lower lipit should be tempered.try putting the filled molds in the fridge to harden.You have to take away the heat that's released by the chocolate as it cools. either with cold air or at least a fan.

Thanks John for giving me some sign to tell the difference between sugar and fat bloom.You got me curious now for that last phrase of your first sentence, "for lots of reasons". Would appreciate more info...please.Rae, I have tried to cool them in the fridge and it does get rid of the bloom. It was the wax and parchment paper experiment that got me. And yes, the tempered chocolate was snappy and shiny.

Right. The molds keep the chocolate warm longer. They act as insulators. Try cooling the chocolate more quickly either with colder air, more airflow, or both.

Alan,Thanks. What you said settles it.But, I still find it amazing that a thin piece of plastic should make so much difference. The spaces in the mold were tiny and not deep (3 grams each, 5mm). If it were possible to measure the temperatures of the chocolate in the mold and the one on the parchment paper cooling down, I highly doubt that there would be any difference.

"Thanks John for giving me some sign to tell the difference between sugar and fat bloom.You got me curious now for that last phrase of your first sentence, "for lots of reasons". Would appreciate more info...please."- I think someone mentioned that moisture could form on the mold before you actually put in the chocolate- the chocolate will set too quickly which, depending on your mold, will lead to lots more bubbles- (Alan please correct me if I'm wrong) If you cool the chocolate too rapidly, one of the unstable crystal types forms, leading to loss of gloss, fat bloom and sensitivity to touch (according to Wybauw).

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

Wow, just awesome.Thank you very much, Alan.First, you trying to diagnose without see things at my place was pretty accurate, using only a few small thermoform molds and lack of air flow in the kitchen.Now to clarify the issue of moisture and pre-cooling of the molds, here is what I did at home.1. I took the tempered chocolate and poured it into the molds and left it on the counter top to cool. Blooming appeared significantly on the underside.2. Then I took empty molds and put it in the fridge to pre-cool. Then I took them out and poured tempered chocolate into them before leaving them on the counter top to cool. I get no blooming on the underside.Although the temperature is warm at 72 F, the relative humidity is very low, so low that our hands and lips are chapped, caused by the propane heat that keeps our house warm. We do not have a humidifier.It seems to me that the cold surface of the pre-cooled molds causes the tempered chocolate to cool faster, leaving less time for the cocoa butter to separate.Another strange thing I forgot to mention at the start of this post is that when I pour untempered chocolate (about 100 F) into the molds that are not pre-cooled and leave them on the counter, I also get hardly any bloom (only a few little white spots). It's pretty shiny, but it melts much quicker in your mouth of course.To conclude, I think relative humidity is so low, it can be ruled out. Therefore pre-cooling the molds would only hasten the cooling of the chocolate.I shall try all this again in the summer when it gets humid.Again, I really appreciate your feedback. I'll be refrigerating now.

My pleasure. Glad I could help.Alan

Hi,

I have had similar problems when moulding my chocolates. Although my problems seams to be with the surface of the chocolate. I am using the chocovision 3Z tempering machine, the chocolate is well tempered but once it goes into the fridge the surface , that is the part not touching the mould become streaked. The rest of the of the chocolate is shiny and has nice snap. I am wondering if there is an ideal refrigeration temperature for chocolate or if the room temperature is affecting the chocolate. The thermometer in the fridge says 38 with 70% humidity. Any suggestions on what could be causing this would be greatly appreciated.

Thanks

Wow...it's been a long time since I've been on this forum. I've since found out that you need to cool the chocolates a lot faster. This will reduce the blooming. It explains why pre-cooling the molds helps. You will get better results putting it right in the freezer and time it for about 5 minutes. After the chocolate is tempered, the faster it cools, the less time it has to form blooming.

Thank you for sharing that. We have been making chocolates in Oregon and I know on the rainy days when the humidity is high we have better success when we put our dipped chocolatesDirectly in the freezer for just five minutes or so. They are shinier as well.