How does a tempering machine work (Pomati)?

Annika von Schlieben
@annika-von-schlieben
10/23/13 09:56:55AM
7 posts

Hi,
I have a Pomati T5 tempering machine, but I can't seem to get the tempering right. I'm used to temper in three steps, heat/cool/heat, but with this machine I can only set one heating temperature and one cooling temperature. How can this work? Or does some magic happends behind the scenes so the chocolate tempers even though it seems like the machine only uses two steps, heat/cool?

The chocolate manufacturer told me to use the following temperatures for tempering their chocolate: 50 C / 26 C / 31 C. Does this mean that I should use 50 C / 31 C with my tempering machine or should the three steps be translated in to something else when I should use only two steps?

I really appreciate your help. Thank's a lot!


updated by @annika-von-schlieben: 04/09/15 08:40:32AM
Carlos Eichenberger
@carlos-eichenberger
10/23/13 02:31:18PM
158 posts

The T5 is a continuous machine, in that it takes care of the heating/cooling/heating inside a set of coils. IIRC you only need to set the high and working temperatures.

Brasstown Chocolate
@brasstown-chocolate
10/28/13 02:15:03PM
14 posts

The machine tempers using a two stage process and works quite nicely when you figure out the proper temperature settings for the bowl and the spout. The working bowl should be set at 45c or there abouts depending on the chocolate you are using. The tempering setting should be between 30 and 32c depending on the chocolate. Everything that comes out of the spout is tempered chocolate. The bowl is kept at 45c and therefore takes the tempered chocolate out of temper. The chocolate then cycles through the screw area where it is tempered again. You might have to adjust the temperatures until you get the combination that works for the chocolate you are using.

Annika von Schlieben
@annika-von-schlieben
10/28/13 07:41:27PM
7 posts
Thank you both! So you are saying that I do not need to change the cooling temperature during the tempering process? Just let it go up to the max temperature (45 or above) and then push the button for entering the cooling phase and when it reaches the lower temperature the chocolate is tempered and ready to use?If I set the working temperature (30-32c) as the "cooling" temperature, will the machine then cool it more than that inside in order to get it tempered correctly? Or should I set the cooling temperature to the lowest (under 29c for dark chocolate)?Should the bowl temperature and the archimedian screw temperature be the same or not?Where is it best to check the temperature manually, in the bowl or the chocolate coming out of the processing pipe? The temperatures shown on the display doesn't seem to be that correct...I really appreciate your time. This is drivning me crazy... :-S
Brasstown Chocolate
@brasstown-chocolate
10/29/13 09:48:53AM
14 posts

When you add your chocolate to the bowl, set the bowl temperature and the screw temperature to 45c. After the chocolate melts turn on the agitator and leaveuntil the chocolate reaches the set temperature.Once 45cis reached, leave for a short while to let the chocolate stabilize. If your are working withchocolate that is already melted then you can turn on the agitator right away and then let stabilize. Once the chocolate is stabilized then turn on the cooling, tempering side of the screw. Set this between 30 and 32c. When that temperature is reached leave it there for a short while to stabilize and then check for temper andmold. Setting the proper temperature for tempering is really a matter of what type of chocolate you are using. If you are not getting a nice temper at 32c then lower to 30c. In addition you might have to adjust the bowl temperature to slightly more or less than 45c to balance out the tempered chocolate. It really is a balancing act but if you lower the bowl temperature to much less than 45c you are going to over temper the chocolate. Hope this is useful information.

Annika von Schlieben
@annika-von-schlieben
10/29/13 10:03:51AM
7 posts
Thank you! I started with only two temperatures but since I wasn't satisfied with the result (after trying several different combinations of temperatures) I thought that mayby I had to make it in three steps like when tempering by hand.Now I know that I should use only two temperatures so I will keep on testing with that. I always get the moduled chocolates to look nice but I'm having trouble to get them out of the modulds (I suppose the chocolate doesn't shrink as supposed). Thank's a lot for your help. I appreciate it!
Clay Gordon
@clay
11/03/13 05:30:43AM
1,680 posts

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.




--
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clay - http://www.thechocolatelife.com/clay/
Esteban Iriart
@esteban-iriart
11/18/13 06:45:49AM
10 posts

Hi, I also have problems with a batch tempering machine. I set the melting temperature to 45 C / 113 F and also set the other thermometer, to cool the chocolate, to 31 C / 87,8 F. However, my chocolate has full of white streaks!! I'm getting crazy!!!

I was trying with 6 kg of chocolate that all process last 1 hour. I also was trying different temperatures, but without success.

I'm very dissapointed.

Any, any help will be SUPER appreciated.

Luis Dinos Moro
@luis-dinos-moro
02/15/15 05:50:17PM
15 posts

I'm looking at the Pomati T5, and was wondering if anyone knew the hourly production rate of the machine, and how long the machine takes to temper.

Thanks

Luis

Clay Gordon
@clay
02/15/15 06:18:00PM
1,680 posts

Luis:

From what I have heard - when you buy Pomati you don't get what you don't pay for. They are inexpensive -- and there are reasons. If you take a close look at the materials and quality of component selection you might be surprised at what you (don't) see.

That said ... in general, the rule of thumb you can use is that the maximum hourly production rate for a continuous tempering machine is roughly 3x the capacity of the working bowl. This assumes that you replace the chocolate you take out of the bowl in a way that does not interrupt the tempering cycle at any time. So, with a 5k working bowl you could expect to get up to 15kg/hr tempering capacity. This is a theoretical figure based mostly on the the rate of flow of chocolate. If you were to empty the bowl by one-third and then put unmelted chocolate pieces into the bowl it could take easily take 15-30 minutes for the machine to come back into temper.

Next, how long it takes to go from melted state to being in temper depends on the rate of flow as well as the difference between the melting point set in the bowl and the temper set point. So - it's going to take longer when the melt point is 50C and and the tempering point is 29C than when the melt point is 46C and the temper point is 32C. There are other things to take into consideration including the heating and cooling capacity of the respective systems. Looking at the wattage, the T5's heating and cooling capacity is not all that high, which leads me to believe it might take longer than with other company's models. But, rule of thumb from melted to tempered suggests that it should be 15-20 minutes.

Reviewing some of Anna's challenges with getting her T5 to work consistently there are two issues I can see without having to open the T5 up:

1) The length of the tempering pipe looks to be very short. This means that the chocolate is not in the pipe for very long. This can lead to inconsistent and incomplete crystal creation and mixing. This is, IMO, a critical design flaw when coupled with what appears to be a low-capacity cooling system.

2) The temperature probe is in the wrong place, so it's measuring the temperature of the chocolate in the wrong place. This is going to affect the feedback loop that governs the tempering cycle (and not in a good way, IMO).

All that said. The T5 is inexpensive. It might work for you, but it might not.




--
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
clay - http://www.thechocolatelife.com/clay/

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