Temperature Questions

[Strangelove]

I'm going to be pulling the trigger on a freezer/controller combo soon, but I'm hoping to have a few things straight before I settle on a size.

1.) Assuming a 3-4 week primary-only, does the wort need to be at 65 the whole time, or can it be moved out once it's at FG? (ambient 68-70).

2.) If racking to secondary, does the secondary go in the freezer?

3.) If it's a barleywine, etc, how long does it need to stay in?

4.) Say I brewed last week and I have a batch in at 65. If I brew this week do I move the probe onto the new fermenter (with ~75 degree wort) and possibly cool the old batch too low, or keep the probe on the old one and allow the new one to cool more slowly?

5.) Am I over-thinking this?

Thanks

 

[BryanJ]

1) Yea you can move it, fermentation temp is more important than when its conditioning.

2) Not unless you add more yeast for some reason or if you are cold crashing.

3) I aged my barleywine about 10 months in a carboy before i bottled it. Its entirely up to you. Id say at least 6 months if its above 10%.

4) Not sure whats going on here.

5) Yes.

 

[pstrohs]

4.) Say I brewed last week and I have a batch in at 65. If I brew this week do I move the probe onto the new fermenter (with ~75 degree wort) and possibly cool the old batch too low, or keep the probe on the old one and allow the new one to cool more slowly?

So, I assume that you are attaching the temp control thermometer to the outside of the fermenter?

I have the thermometer to my fermentation chamber measuring the ambient temperature so I make sure that I keep the temp set lower than my desired fermentation temperature. This is because the temp of the wort can be anywhere from 2-10 degrees warmer than the ambient temperature during active fermentation.

 

[Tiredboy]

Not wanting to hijack the thread but assuming I wanted to use a converted chest freezer as a fermentation chamber, could I keep other foodstuffs in it also or would they does it get aromatic and would I expect the other foods to take on a beer flavour/aroma?

 

[Cacaman]

Not wanting to hijack the thread but assuming I wanted to use a converted chest freezer as a fermentation chamber, could I keep other foodstuffs in it also or would they does it get aromatic and would I expect the other foods to take on a beer flavour/aroma?

If they're sealed I'm sure they'll be ok.

 

[cwi]

4.)
So, I assume that you are attaching the temp control thermometer to the outside of the fermenter?

I have the thermometer to my fermentation chamber measuring the ambient temperature so I make sure that I keep the temp set lower than my desired fermentation temperature. This is because the temp of the wort can be anywhere from 2-10 degrees warmer than the ambient temperature during active fermentation.

That is why attaching it to the fermenter works so well. You don't need to include yourself in the control loop as second controller.
vessel wall|probe|insulation|(tape, bungy, velcro, strap, etc.)

 

[cwi]

4.) Say I brewed last week and I have a batch in at 65. If I brew this week do I move the probe onto the new fermenter (with ~75 degree wort) and possibly cool the old batch too low, or keep the probe on the old one and allow the new one to cool more slowly?

It really depends on what your tolerances are for temps. How tight do you want to control the temps?

That said, there is no feasible way to accurately control the temps of many vessels with one controller if any of the vessels are exothermic. One solution is to control the ambient with the probe on the most exothermic ferm, and use heat belts (with controllers) for the least exothermic vessels. You could also heat belt all of them, and set the ambient low enough to account for the most exothermic vessel.

For vessels that have no yeast activity you are concerned with controlling (like bulk aging), the temp variation they experience due to controlling the exothermic vessel won't hurt anything. For vessels that may still have some activity, like a batch 1 week old, you may still care about not affecting the yeast with temp swings. In this case, with only one controller, most would say to control to the new batch.

You are adding in some extra complexity as you are implying that you need to ramp the new batch down to pitching temps from 75F.

 

[cwi]

If they're sealed I'm sure they'll be ok.

Are you talking about storing food and fermenting simultaneously?

As long as the foodstuffs don't spoil at 65F. I can't think of anything that can be kept at 65F without spoiling that can't also be kept at room temp. If you are lagering, maybe it would work as a fridge.

 

[Strangelove]

Thanks for the answers. Pretty much what I thought, but it's always good to have input from the experienced. If I only need to keep them at a strict temperature for 1-2 weeks I can get a smaller freezer.

As a follow-up, how do most set their controllers? I understand that you can change how often the controller activates the freezer's compressor.

 

[cwi]

Thanks for the answers. Pretty much what I thought, but it's always good to have input from the experienced. If I only need to keep them at a strict temperature for 1-2 weeks I can get a smaller freezer.

As a follow-up, how do most set their controllers? I understand that you can change how often the controller activates the freezer's compressor.

Things that change how often the compressor activates are the temp differential setting, heat of ferm, probe placement, ambient temps, etc. See my post above for a vetted probe strategy. Use at least 1/2" of decent insulation. Too much insulation is not an issue to be concerned with.

With that probe strategy, and a 5 gallon carboy, you can set the actual differential to ~1F with no issues. Some controllers have screwy ways of arriving at the temp setting, so read the manual thoroughly.

Some controllers have Anti-Short cycle Delay (ASD), which prevents the compressor from activating shortly after it has just run. I would not own one that does not have ASD. This should usually be set to the maximum- ~10 minutes, or even a bit longer. Shorter than 5, and you risk damage to your compressor.

Check out the ebay aquarium controller thread. Dual stage for $25 + $5 in parts and ~1hr DIY.

 

[cwi]

If I only need to keep them at a strict temperature for 1-2 weeks I can get a smaller freezer.

The size that can hold a sanke 1/2 barrel are nice in case you ever want to turn it into a kegerator. That size is around 15CF these days. Older smaller ones (7CF) were wider front to back and could hold a keg. Newer ones, even some 14CF ones, can't. Bigger than 15CF seems impractical to me. I would rather have multiple smaller ones, but still have at least one that could fit a sanke.

 

[pstrohs]

Thanks for the answers. Pretty much what I thought, but it's always good to have input from the experienced. If I only need to keep them at a strict temperature for 1-2 weeks I can get a smaller freezer.

As a follow-up, how do most set their controllers? I understand that you can change how often the controller activates the freezer's compressor.

I have a Love dual temp controller and have my main settings set as follows:

SP1: 64 (temp for fridge)
SP2: 59 (temp for heater)
R1: 1.5 (fridge will kick on at 65.5 (64 + 1.5))
R2: 1.5 (heater will kick on at 57.5 (59 - 1.5))
C0: 25 cycle time for fridge and heater will be ≥ 25 min.

These are really the only settings that I ever change on my temp controller. I will raise C0 if I don't want my fridge to cycle too often and change SP1 and SP2 depending on my desired fermentation temps.

 

[cwi]

I have a Love dual temp controller and have my main settings set as follows:
C0: 25 cycle time for fridge and heater will be ≥ 25 min.

These are really the only settings that I ever change on my temp controller. I will raise C0 if I don't want my fridge to cycle too often and change SP1 and SP2 depending on my desired fermentation temps.

Parameter C0 is minimum off time, and is equivalent to ASD. It is usually used to prevent hot starts of the compressor. 15 minutes is more than enough to prevent compressor damage for a standard freezer. 25 min might unnecessarily impact your temp control. Widening the temp diff will be more predictable, and spare your compressor at the same time. In practice, the cooling cycle generally won't re-activate under 10 minutes unless something strange happens like a door opening shortly after a cycle ends. Probe placement is a factor as well.

From the looks of it, C0 doesn't discriminate between cold or heat relay activation. Most purpose built controllers for compressor cooling and resistive heating will only apply ASD to the cooling cycle.