How does a tempering machine work (Pomati)?
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Tech Help, Tips, Tricks, Techniques
Annika -
Most smaller continuous tempering machines are two-zone, some are three. In a two-zone machine you set the temperature of the working bowl and then the temperature of the cooling pipe. The temperature of the working bowl is set high enough to melt out all the crystals. The temperature of the cooling pipe is set to generate enough crystals so that the chocolate is properly tempered when it exits the spout. Any chocolate that is not used goes back into the bowl where the crystals are melted out before the chocolate re-enters the cooling pipe. The cycle is not interrupted which is why it's called continuous (as opposed to batch) tempering.,
The actual temperatures you arrive it will probably be different from the ones you use in a batch tempering machine like a Chocovision. You can use the high and low temperatures the manufacturer recommends as the starting points, but don't expect them to be right. You will need to experiment to find the correct temperatures. What those are depends on a complex set of factors - the viscosity/rheology of the chocolate, the overall size of the machine (capacity), the power of the compressor, and more.
Also, never expect the temperature of the chocolate in the working bowl to be even, or the same temperature from the sides to the center and the top to the bottom. What you care about is the temperature of the chocolate as it leaves the working bowl and if all the crystals are melted out. (Think about it - you are dropping chocolate from the cool point into the top of the chocolate in the work bowl, which is warmer, and mixing it up. It takes time for the chocolate to warm up, and that will be towards the bottom of the working bowl.)
In general, as you modify temperatures, you want to work towards the lowest temperature in the working bowl that works for you, and the narrowest range of temperatures between the working bowl and the tempering pipe. This will reduce overall energy consumption and mean that the compressor is not working harder than it needs to.