Posted by gerard on January 24, 1999 at 20:04:42:
In Reply to: Re: tempering chocolate posted by Pierre on January 24, 1999 at 18:45:30:
Pierre
Definately no gadget, costs a few thou.
Mfgered by Stoller in Germany.
Its a self contained refrigerated unit with graph print out, the whole machine is no bigger than a lunch pail.
A sample is placed inside and it does an instant cool down and prints out the degree of temper in graph form, a reverse S on the graph is thought to be perfect but slight deviations are acceptable even for mass production of 5000+lbs daily.
Its an ingenious process, imagine a single crystal element such as ice, as it warms it absorbs heat at a given steady rate until it reaches 32, at this point it stops getting warmer because the energy (heat) is absorbed by the crystal breaking down(melting).
After the ice crystal has broken down(melted duh!) the heat is released and this latent heat can be measured.
Choc works in the opposite direction but the process is similar plus choc is a multi crystal element but it does the same thing.
Chocolate cools at a predictable rate until it reaches the point of crystalization, at this moment the heat ceases to be released because the energy is absorbed into the formation of alpha/beta crystals whatever.
Immediately after the stable crystals form (alphas?) latent heat is released and its this latent heat or stored energy that the Stoller machine measures and converts to graph form.
Depending on the useage of the choc you can attain different tempers, its nice to get that extra bit of shrinkage (1 1/2%) when molding.
Its kinda obvious that the type of tempering we do as pastry chefs is rudimentry and sometimes a shot in the dark at best.
I'll try to get a price on it, the voltage will need converting.
The more I find out about choc the more I realise I don't know anything.
Cheers, Gerard