19 replies to this topic

[positiveContact]

Last night I set the temp chamber to chill 10 gal of wort down to 2C.  airlock and a couple of water bottles are frozen solid.  beer not frozen at all.  this has never happened in the past so the only thing I can think of is that the new insulation I put on the probe is giving me a better read on the beer temp.

[3rd party JKor]

Sounds about right.  I've noticed that the temp from my probe drops fairly quickly when the AC kicks in.  Way faster than the entire mass of wort would cool down, then when the AC goes off it slowly creeps up over the course of a few minutes (at least when I first put it in the chamber).  I've equated this behavior to one of two things, either the probe isn't insulated quite enough (although it's pretty well insulated) or there is a layer of wort that cools faster around the outside of the fermenter then after the cooling stops the cool outer layers mixes with the internal fluid and evens out the temp.

 

It definitely gets below freezing in the chamber, but never long enough to freeze anything.  

[positiveContact]

Sounds about right.  I've noticed that the temp from my probe drops fairly quickly when the AC kicks in.  Way faster than the entire mass of wort would cool down, then when the AC goes off it slowly creeps up over the course of a few minutes (at least when I first put it in the chamber).  I've equated this behavior to one of two things, either the probe isn't insulated quite enough (although it's pretty well insulated) or there is a layer of wort that cools faster around the outside of the fermenter then after the cooling stops the cool outer layers mixes with the internal fluid and evens out the temp.

 

It definitely gets below freezing in the chamber, but never long enough to freeze anything.  

 

well in my case it appears it was lack of insulation.  I'm guessing the probe was picking up a combination of air and liquid temp.  I think more insulation will be better for the chest freezer in the long run (less cycling) but I'll have to be careful if I have kegs or something in the chest freezer and I attempt to cool something else that isn't already pretty cold.  things to keep in mind!

Edited by Evil_Morty, 07 October 2015 - 04:58 AM.

[3rd party JKor]

Wouldn't less insulation on the probe make the chest freezer run less?  If the probe is more susceptible to the air temp then it will read a lower average temp, causing the freezer to shut off sooner.  

 

I'm having trouble reconciling that with the frozen airlock and water bottles.  

 

Was the wort warmer than normal?  Was your wort volume larger?

[positiveContact]

Wouldn't less insulation on the probe make the chest freezer run less?  If the probe is more susceptible to the air temp then it will read a lower average temp, causing the freezer to shut off sooner.  

 

I'm having trouble reconciling that with the frozen airlock and water bottles.  

 

Was the wort warmer than normal?  Was your wort volume larger?

 

I wouldn't think so.  The extra insulation would mean I'd be reading more wort/beer temp and less air temp.  the air temp is going to vary a lot more and move a lot faster than the liquid temp.  The beer was at something like 18C when I se the controller to bring it down to 2-3C.  so b/c the probe was well insulated I'm guessing the chest freezer ran for a long time.  The airlock and the 2L soda bottles are relatively small volumes compared to 10 gallons of beer so those would cool off quickly and subsequently freeze before the beer was down to 2-3C and the chest freezer turned off.

 

what I meant by run less is that now that the beer is cold even if the air temp goes up in the chest freezer it's going to be a while before the beer temp drops and the freezer cycles back on again.  so when the freezer runs it will run longer but it won't be turning on/off as often.  I have to think this is better for the compressor.

Edited by Evil_Morty, 07 October 2015 - 06:43 AM.

[3rd party JKor]

But as long as the wort temp is above the setpoint the freezer should be running continuously.  The closer your probe is to the actual wort temp, the longer the freezer will run.

 

Hypothetically, if your probe was always at the exact temp of the wort the freezer would run continuously until the wort reached the set point (unless you have some PID parameters set, in which case it would dampen the response as you got closer to the SP).

 

That would be the worst case scenario for freezing other things in the chamber.

[positiveContact]

But as long as the wort temp is above the setpoint the freezer should be running continuously.  The closer your probe is to the actual wort temp, the longer the freezer will run.

 

Hypothetically, if your probe was always at the exact temp of the wort the freezer would run continuously until the wort reached the set point (unless you have some PID parameters set, in which case it would dampen the response as you got closer to the SP).

 

That would be the worst case scenario for freezing other things in the chamber.

 

I agree with what you are saying.  I was talking about the freezer cycling on/off more b/c of the lack of insulation.

[3rd party JKor]

Ah, OK.  I wasn't following.  It would be better for cycling less.

 

Although, I wonder why you'd never seen the bottles/airlock freeze before.

[SchwanzBrewer]

I read this as you were insulting your probe. That's probably bad juju for the beer.

[positiveContact]

Ah, OK.  I wasn't following.  It would be better for cycling less.

 

Although, I wonder why you'd never seen the bottles/airlock freeze before.

 

I think b/c the temp probe would think I had hit the target temp when I had not and shut off.  then the air would warm up a little and then it would kick on again.  it would slow down the rate that I was cooling the beer which would mean I'd never sustain sub-freezing air temps for nearly as long.

[positiveContact]

I read this as you were insulting your probe. That's probably bad juju for the beer.

 

I'm nice to all of my equipment

[3rd party JKor]

I think b/c the temp probe would think I had hit the target temp when I had not and shut off.  then the air would warm up a little and then it would kick on again.  it would slow down the rate that I was cooling the beer which would mean I'd never sustain sub-freezing air temps for nearly as long.

 

 

Doh!  I totally missed that you had actually insulated it more this time.  For some reason I was thinking that you just realized you *need* to insulate it more because your airlock froze.  i'm not sure why I took it that way.

[djinkc]

I have my sensor in a thermowell inside a White Labs vial filled with water.  It's suspended outside of the fermenter.  A cheap Taylor indoor/outdoor reads the temp inside the fermenter from another thermowell.  This seems to work well for keeping my fermentation temps where I want them.

[positiveContact]

Doh!  I totally missed that you had actually insulated it more this time.  For some reason I was thinking that you just realized you *need* to insulate it more because your airlock froze.  i'm not sure why I took it that way.

 

this all makes a lot more sense now! 

[bigdaddyale]

What are you guys using for controllers? I built a dual probe STC1000+ ver.8 but haven't use it yet.

[positiveContact]

What are you guys using for controllers? I built a dual probe STC1000+ ver.8 but haven't use it yet.

 

stock stc1000.

[neddles]

stock stc1000.

same

[gnef]

My stuff is all from before the discovery of the STC controllers.

 

I use Love digital temperature controllers. I believe I paid around 50-60 per controller, an earlier model came with the probe, and I remember the later model I bought, TS-2, that did not come with probes.

 

I like them, but they rose in cost very quickly, and they don't provide any advantage over the STC controllers that are out now, especially the heat and cool ones, and if you have the ability to flash it.

[positiveContact]

My stuff is all from before the discovery of the STC controllers.

 

I use Love digital temperature controllers. I believe I paid around 50-60 per controller, an earlier model came with the probe, and I remember the later model I bought, TS-2, that did not come with probes.

 

I like them, but they rose in cost very quickly, and they don't provide any advantage over the STC controllers that are out now, especially the heat and cool ones, and if you have the ability to flash it.

 

higher amp rating on the SSR I'm guessing and longer life are still advantages.  on price the STC is hard to beat!

[3rd party JKor]

It's never too late for TWSS, right?