[DanBricker]

I am trying to get my Fermentation system to be able to lager.



My Glycol Chiller is capable of getting to 14F no problem. When I set my equipment to chill my fermenter to 35F it can get to 40 and then flat lines. I have had a little icing when I was at 14F. I adjusted my Glycol temp to 35F and have still not been able to get the fermenter to drop below 40F. It is a 1/2 barrel Fermenter with a 3/8" tube SS 3" coil. Im using a 5000 BTU AC unit with a 48qt reservoir. The graph above shows where it flatlines at 40F we had no icing inside the unit.

[durschad]

Is the glycol pump on a temp controller or are you constantly circulating?  I'd try setting the temp on the glycol as low as it goes and only circulate when the beer temp is above the 35 degrees you want.

[DanBricker]

Yes the glycol is on a temp controller and it can hold 14F while circulating Fermenter 3 but fermenter 3 will not get below 40F.


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[kylekohlmorgen]

Sweet graphs. I'm a process/automation engineer by day, so I'm gonna dig in here.

1. I'm assuming this is just a test? During an actual fermentation/lagering, chilling the beer 20F in 4 hours is way too fast. Go for 1-2F over the course of a day.

2. You'll never drop your fermentor temperature to the temperature of the glycol. This is why the temp flatlined ~ 40F when your glycol was 35F - the temperature difference wasn't large enough to transfer heat.

Think about cooling your wort on brewday. The wort temp cools to several degrees above the cooling water temp. Instead of raising the glycol temp, just recirc when cooling is needed.

3. What is your glycol/water mix? The more water, the better the heat transfer. 50/50 is usually a good blend of freeze protection and heat transfer. I would expect that 35-40F would be a good setpoint for primary fermentation, and 25F-30F would be good for maintaining lager temps. Depends on coil dims, insulation, ambient temp, etc.

4. Have you checked calibration on your temperature sensors? If you don't have a calibration thermometer, check them against a few of your brewday thermometers.

MOST IMPORTANTLY:
Can you post more pics of this fermentor, the chiller, and the controls? I would love to see it!

[DanBricker]

1) yes just a water test at the moment.

2) we flatline even when the glycol is 14F.

3) we are at a 33% mix at the moment. allowing approx. -3F in the chiller lines. 

4) We have not calibrated in a while.


Pics) Soon. Have to clean it up a bit.


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