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Control viscosity
February 23, 2005
5:22 pm
Polarbear
Tromsø, Norway
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April 24, 2004
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I tried to make some new truffle pralines this weekend, both molded and enrobed. I have fixed the grain problem, it was as expected either too high temperature or moist. The big problem now seems to be the viscosity of the choc. It is to thick, so the moldings become to thick. Any smart way to make it float better, or do I simply have to find another choc?

***
My name is Polarbear and I am a chocoholic…

*** My name is Polarbear and I am a chocoholic...
February 23, 2005
5:47 pm
chocolatero
london
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September 5, 2004
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Hello
Long time…
You have to find our whether the choc is inherently viscous or whether you are not handling it properly
the viscosity is linked to TOTAL % of cocoa butter (i.e. what is in the cocoa mass about 50%) amd the rest that has been added by manufacturer to make it easier to use. Thick chocolate (cheaper as cooca butter is expensive) could have as low as 32% cooca butter; very fluid would have 44-44%. The manufacturer should be able to tell,
although they like to keep it a secret. ASk for TOTAL% of cocoa butter.
If it is not the chocolate itself, it may be how you are treating it.
Several things could happen
1) not heating the chocolate enough, therefore not fully decrystallize. go up to at least 50-55degrees
2)tempering too slowly. The faster the better. all got to do with the crystal structure you get. Cocoa butter is a very complex fat and therefore hard to work with…
3) tempering too low in temperature. ideally keep 1/5 hot to conpensate. could should also temper at 30 but work slightly higher
by reheating a bit
4) working in cold or humid environment

Got to go and make Easter eggs….
Chocolatero

February 23, 2005
7:21 pm
Sebastian
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September 30, 2004
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Building on that..

If the chocolate starts out fine, but thickens over time as you work with it – this is expected, and can be addressed by *Slowly* heating the chocolate by 2 or 3 degrees F. If you get it to warm, you’re going to break your temper entirely.

You also may be able to lower the viscosity by adding 0.1-0.2% of fluid lecithin, available at many specialty shoppes. Adding too much of it will result in it thickening the product, but adding just a slight amount often works wonders in terms of rheological depression.

As for the total fat content, the mfr should be able to tell you very quickly what the fat and viscosity should be – every chocolate product made will have these two items specified by internal, and probably external, specifications. Most chocolate viscosities are read in degrees Brookfield or equivalent (anything below a 30 should be ok for moulding – the lower the number the more fluid it is). If it’s in MacMichael, you’re probably going to want something 120 or below, but hardly anyone uses this method anymore (its so old, parts can no longer be had for the equipment). Some places may express it in cP (centipoise), and I’d have to look up conversion numbers to tell you what those should be..

alternatively, you could also add pure cocoa butter yourself (be sure to temper the mass after you add the cocoa butter…).

February 24, 2005
1:09 am
Hans-Peter Rot
USA
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August 1, 2006
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Like they said [;)]

February 28, 2005
10:09 am
Polarbear
Tromsø, Norway
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Thanx a lot for all the advice! I think the main problem has been to low temperature (of fear of getting too high temperature…) and inherent viscoud choc. The choc I used was a cheap 50% baking bar, so a low cocoa butter content makes sense (it did not contain other funny fats). The reason I used it is simply that I will need a lot of choc to mess with when I practice. The cheap choc costs €1 per 100g, while a 70% G&B costs €4 and a Valrhona or Cluizel at least €5. May be a drop of vegetable oil could help, even if it is a kind of heresy?

***
My name is Polarbear and I am a chocoholic…

*** My name is Polarbear and I am a chocoholic...
February 28, 2005
11:39 am
Sebastian
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Probably not. Mixing oils is usually a very, very tricky thing, as you’re going to run into something called ‘eutectics’ meaning, that you mix two oils that are usually solid at room temperature, the result isn’t likely to be what you’d expect – the result probably won’t be solid at room tem perature, and you’lre going to ahve troubles tempering. there are exceptions – shea and illipe oils can be mixed into cocoa butter, but they’re awfully hard to find…

February 28, 2005
12:27 pm
Polarbear
Tromsø, Norway
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Thanks, Seb! If I understand you correctly, the problem will be that the two fats have different melting temperatures and will therefore separate to two different phases?

It’s fun for me as a geologist to see the similarities between chocolate and geology – the same “problems” arise when melts cool down to form solid rocks; minerals of different melting temepratures/pressures will separate. And the reason that chocolate needs to be tempered is due to cocoa butter being polymorphous, that is one chemical compound can crystallise with different structures depending on P-T-conditions. The most known is diamonds and graphite, which both are pure carbon, C. Ordinary silica, SiO2, actually has six different polymorphs, quartz is the most common.

http://www.waynesthisandthat.c…../tempering

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My name is Polarbear and I am a chocoholic…

*** My name is Polarbear and I am a chocoholic...
February 28, 2005
4:09 pm
Sebastian
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Sort of. What happens isn’t so much that it striates due to varying compositional or physical delinations, but rather that they’ll interact with one another, resulting in a net yield of something that’s not quite what you’d expect. IE, if you’ve got 1 kg of an oil that has a mp of 30C, and 1kg of an oil that has a mp of 35C – if you mix them together, you’re not going to get 2 kg of an oil at 32.5C – it’ll likely be depressed, and you may end up with 2kg of an oil at 27C. It also will interfere with your ability to temper, and if you add even small amounts, it’s likely to make it darn near, if not absolutely, impossible to temper.