Glycol / Stratification

[Bainbridge]

So our glycol system is oversized for our current setup (expansion plans later on) so it does a really good job. Too good. We're having trouble getting the probes in our uni's to show 34, beers seem to stop around 38-40.

System: four 10bbl double jacketed tanks, jackets ran in parallel. Glycol's 10 horse, running 26 degrees and 15 psi. Didn't think stratification would be a major issue at this size but apparently it might be. Don't think we've eisbocked it.

Anyhow: thoughts on how to do a controlled crash of the beers without this happening? And how to mix the ones that already are crashed? Trying not to re-mix the finings and cone gunk if possible.

Trying to get a protocol in place. Thinking:

• Main Ferment - Top jacket open 50%, bottom closed. It's rolling anyway, don't want a cold pocket forming on the bottom.
• Secondary - crack bottom open a bit, 10%. Things are settling, want to compact the yeast cake.
• Crash/Dump/Fine - Drop to 40, open bottom valve 50% and close top to 10%? Don't want top to become more dense than bottom. Use fining injection through upturned racking arm to mix things a bit.
• Final rest - drop to 34 - open top to 50% until everything balances out?

As for the existing tanks we're thinking:
- up the temp on the glycol and pump it around 34 degrees?
- pump over to another uni to mix?
- bubble co2 up the drain port?
- turn the racking arm up at an angle and bubble through it?
- recirc through racking arm, with de-o2'd water to prime the pump?
- some kind of cycle between the jackets, 15 minutes on top, 15 on bottom, etc to try and get a current going?

Anyhow, going to go chip some ice off my valves now.

[PruBrew]

Controller differential

Check your differential on your temp controller. Doesn't sound like a stratification issue from the way you've described it...

[Bierkoenig]

I'd second that. Sounds like the controller is not getting an accurate read. What type of temp probe? Did you test it with boiling water and ice water or against a known accurate thermometer (with the same length of thermocouple wire or probe extension)?

[Bainbridge]

Hmm. The solenoids are controlled by some Johnson Controls on the wall. All new and the differential is set at 1 degree. The termometer probes are stuck down at the end of the tanks' thermowells, ran through and secured by plastic conduit. Could be they're getting a poor read off that I suppose.

[PruBrew]

Have you tried physically double-checking the temp of your beer with a handheld digital thermometer from various access points in your tank?
Chances are that your sample port and thermowell are roughly at the same level, so that will at least give you an idea if you are having probe calibration/conduction issues.
The problem, the way you described it, is that your setpoint on your control is 34 degrees, but your temp readout on the control never falls below about 38. If that is the problem as you're seeing it, then there could be a whole host of issues going on, but temperature stratification is pretty far down the list.
First issue to check is if the control is still calling at 38 or not.
If I've missed some other piece of the puzzle, fill us in.
Cheers & good luck.

[jvandenbrink]

Thermal Mastic or Air?

A couple things come to mind as possibilities.

1. Sounds like your thermowell might not be conducting correctly or ambient air is sneaking into the thermowell to give it a little higher temperature. I had this issue and resolved it with this stuff.

http://www.grainger.com/Grainger/VIRGINIA-KMP-Thermal-Mastic-4E847

2. Do you have a way to bleed air from your glycol loop? In the past when I had troubles getting beer down to temp it was because I had air in my top jacket (mine are run in parallel as well). I found that ice formed on the lower jacket but not on the top when this was the case. If you don't have an air bleed in your loop then make sure the tank is calling for glycol and loosen the "out" port on your top jacket and you will hear air hiss out. do this repeatedly until all air is evacuated. If air returns then you have a flow problem.

Good luck.
Joel
Two Beers Brewing Co.

[Bierkoenig]

Joel,

How many thermowells could you treat with that tube? And did you fill the whole well or just pack the end? The stuff is a little tricky to get it where you want it. I've thought of using a syringe with a long tube attached to the tip.

[Bainbridge]

Sorry for the delayed reply, we were waiting on our new 24" long thermocouple probe. (I dub thee Excalibur!)

Took some measurements. On our kolsch, the thermostat was set at 34 but read 36. Lot of ice buildup on the valves from the constantly running glycol. Measurement down the dryhopping port to the top of the tank was 30, but no ice thankfully. Getting 38 out of the sample port. (Basically on the same level as the thermostat probe.)

Ordered in some thermal mastic like you suggested Joel. Talked to Alex and he said his all read the same after it (the same, not necessarily "accurately" We'll see what it does. L&I made us conduit in our thermostat probes, so putting the paste in will be fun...

[Bierkoenig]

Keep in mind that the temperature of samples taken from the sample port will be higher than the beer in the tank for a couple of reasons:

First, the beer sitting in the port is a little warmer because it's separated from the outside air only by the metal of the valve assembly, so it's a warm point.

Second, if the beer is carbonated, the gas breaks out of solution as soon as it emerges from the short sample spout into the atmosphere. This energy release warms the sample. With 2+ volumes of dissolved CO2, it can be several degrees. Compare samples taken from a sample valve versus a zwickel and you'll see the difference.

[jvandenbrink]

I was able to do a handful of tanks with one tube of thermal mastic. I use the Ranco ETC's and so the actual probe is only a couple inches long. I would put on as much as I thought reasonable, but the probe in the thermowell and repeat a couple times until it seemed sufficient. I've now done that with 16 tanks and I'm on the same tube.

I hope it works for you Bainbridge. Best of Luck and I can't wait to try your beer.

Joel

[Bainbridge]

Yeah, I pulled about three 5oz samples from the port so it wasn't drawing right from the beer in the port. First sample was like 50 degrees!

Moved it to the brite today. No ice inside, and brite read 37. It's a mystery. But the mastic is on its way.

Going to make it out to Bremerton next weekend Two Beers?