Temperature stratification before fermentation starts

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Jtvann

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Wondering what you all do if anything about temperature stratification before active fermentation starts. Once fermentation is going strong, everything stays pretty good and mixed around. I hadn’t noticed stratification to the level I’ve seen until my current batch.

I recently bought a new tilt hydrometer pro. Out of the box, I thought the temp reading was wrong on it. I didn’t care too much because I don’t use it for temp readings. The SG readings were spot on.

I also use a Ssbrewtech 14g unitank. My FTSS controller was set to 68 degrees and read perfectly 68 degrees upon pitching yeast. It varies in that 1 degree range between 67-68.

Looking back at my tilt though, it read as high as 79 degrees. I really didn’t trust it, but that was before fermentation really started. Looking at the graph, as soon as actually vigorous fermentation has kicked off, both my tilt and ftss agree exactly on what the temp is and has continued to agree.

So it makes sense that the tilt reading from the top would read higher than the ftss reading from the middle, but 10-11 degrees higher is surprising.
 
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Jtvann

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Now fermentation is barely slowing down. Temp is mostly still holding fine, but it did tick up to 69 once. My bet is that as it continues to slow more and more that my stratification comes back. Especially during cold crash.
 

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I always calibrate the temperature and SG in the Tilt app to the known temp/SG at the beginning of fermentation. I haven't noticed any issues with the temp on mine. It seems spot on for temp; it's SG that I don't trust (and use only for trending).

I'd be surprised at that much stratification without a heating source of some kind. After this batch is packaged, maybe run a test in a cup of water. See what your Tilt says for temp and compare to another thermometer you know to be accurate. That still doesn't tell you anything about why it would change with fermentation, though.
 
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Jtvann

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So for some context. I’m brewing in my garage. Temps dip to near or below freezing sometimes. I am heating by running warm water through the chiller coil. Heat is not coming from the bottom and rising up.

I’m worried the heat is all going to the top and not registering on my ftss probe. As soon as active fermentation kicked off and mixes things up, temp was accurate throughout.

What do I do for the 24 hours before, when it’s hot at the top?
 

Vale71

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Place a heating pad on the cone and heat with that. This will cause convection and better temperature distribution.
 
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Jtvann

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I’ve got one of those, but they don’t put out enough heat. It’s good for at most about 20 degrees.

It’s 22 degrees outside right now.

I was looking for a bigger or more powerful heat wrap that I could use. Hopefully something that the ftss controller can use, but not an absolute must.
 
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Jtvann

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Temp range for safale 05 is 53-77. I did exceed the upper end of that briefly. I don’t think this is going to have a huge impact on my beer. Just trying to figure out what to change going forward.

I could lower the temp at first to the low 60s to average out the top and bottom temps to try and keep them both in range, then increase to optimal temp after 24 hours.

I could also find a more powerful heat pad to put on the bottom of the unitank.

Looking for any other ideas, or problems with either of these solutions.
 

Vale71

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Are you pumping the hot water from the bottom up or vice versa? Although that's probably not going to make much difference being that the coil in the SSB Unitank barely reaches below the temp probe.
If your garage really dips below freezing and considering that the insulation in the Unitank is nearly non-existent there is a real possibility that the only effective solution is some sort of insulated cabinet to put your Unitank in and then using the heating pad? How powerful is the one you're using now?
 
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Jtvann

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The garage is uninsulated. It’s 34 right now in the garage. That thin neoprene is more for looks than actual insulation I think.

Not sure what you mean about pumping from the bottom up. It’s just going through the chiller coil loop.

The heating pad is the supplied one with the ftss system. It covers a decent part of the cone but is just warm to the touch through the neoprene.

I think when I’m done with this batch I’m going to just fill it with water and turn the heating pad on set to 90 degrees. I’ll let it set a few days and test what the capability of the pad really is. That ought to tell me what it’s really able to do with no yeast movement.

I’ve lowered the temp down to 65 on the ftss for now just to keep it from going too high. This fermentation ran hot for sure. I had to open my garage door at one point in day 2. Garage temp was in the upper 50s, and temp shot up above 68. I don’t have any cooler mechanism when I’m using the chiller coil to heat other than ambient temps.
 

Vale71

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Not sure what you mean about pumping from the bottom up. It’s just going through the chiller coil loop.
One of the coil attachments shoots straight to the bottom of the coil. This should be your "in" side when heating with warm water, this way the bottom of the coil will be the warmest part with temperature steadily decreasing as you go towards the top and this will encourage convection.
 
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Jtvann

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Are you pumping the hot water from the bottom up or vice versa? Although that's probably not going to make much difference being that the coil in the SSB Unitank barely reaches below the temp probe.
If your garage really dips below freezing and considering that the insulation in the Unitank is nearly non-existent there is a real possibility that the only effective solution is some sort of insulated cabinet to put your Unitank in and then using the heating pad? How powerful is the one you're using now?
I see what you mean now on the down/up loop. One keg of the coil goes straight down. I’ll have to check my arrangement on the next batch.
 

Vale71

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As to the temperature control I assume you're using warm tap water with the water then going down the drain after a single pass instead of back into some sort of reservoir? Even in that case it's possible to rig a solenoid valve controlled by the FTSs that will only draw warm water when needed.
 

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I have to agree with @Vale71. The shortcoming of coil chillers (heaters) is that they radiate heat outward from the coil. Until the heat/cold differential at different points in the fermenter becomes great enough to set up a convective vertical mixing you're going to see what appears to be a stratification but is probably just your temperature probe being in close proximity to the coil being rapidly heated by the infusion of warm/hot water. When I turn down the cooling demand temperature setting on my controller I can see an immediate 3-4F drop in the temperature display. Conversely when I increase the temperature (activate the heating pad at the bottom of the unitank) it takes quite a while to start seeing any temperature increase, and it is gradual without sudden spikes.

Now according to Spike Brewing, a significant stratification occurs while cold crashing when the tank reaches 40F. They recommend reversing the input/output lines of the glycol tank. I've observed that phenomenon in my own setup when is seems to stall at 38F and won't go any lower until I cross the glycol lines. Even after that I can only get the tank down to 34-35F (insufficient insulation is my guess), but I don't think that's the issue you're experiencing. I think you are probably seeing the temperature probe responding to a rapid temperature rise in your coil.
 

Vale71

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Good catch. Since he has warm water running through the coil all the time and since the Tilt is free-floating it's posible it has become stationary in the vicinity of the coil and is being more or less directly heated by it.
 
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Jtvann

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Good catch. The tilt pro is big. So big it can’t fit inside the chiller coil. It has to go on the outside between the tank wall and coil.

It’s probably showing the heat from possibly even touching the coil from time to time.

While it probably is a little warmer, it’s likely not actually 10 degrees warmer in the actual beer.

Ssbrewtech suggested lowering the temp of the heat water some. I’ve been using a regular cooler with a fish tank heater set to high. Heat reservoir is probably in the 80s. I could turn that down to the 70s and have the pump run more frequently.
 

JoeMamasIPA

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What are your thoughts on the Tilt Pro? Or if there is another thread with Pro opinions steer me there. I didn't see one.
 
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Jtvann

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I didn’t know about it either until I went to buy a regular one.

It’s big. Twice the size if not more than the regular one. That benefits from being more stable in a violent fermentation. It’s still not perfect though as you can see my graphs. There’s swings still, but they do seem a lot more tame than the regular version. A huge difference is transmission through stainless. The signal is strong. I’ve not lost connection a single time, and it registers quickly.

It’s powered by 2 AA batteries which are cheaper and easier to find than the CR123. Batteries supposedly last up to 5 years. We will have to wait and see on that.

It’s accurate out of the box with no need to calibrate.

It’s got a sort of cone shape to it for maybe having krausen slip off easier.

I like mine more than the regular version, but as always in my opinion, a tilt is a nice and cool thing to have. It’s not a need.
 

Brooothru

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Good catch. The tilt pro is big. So big it can’t fit inside the chiller coil. It has to go on the outside between the tank wall and coil.

It’s probably showing the heat from possibly even touching the coil from time to time.

While it probably is a little warmer, it’s likely not actually 10 degrees warmer in the actual beer.

Ssbrewtech suggested lowering the temp of the heat water some. I’ve been using a regular cooler with a fish tank heater set to high. Heat reservoir is probably in the 80s. I could turn that down to the 70s and have the pump run more frequently.
Longer runtimes at a more moderate temperature is probably a good idea and will avoid any large spikes or swings that could affect the fermentation. There's always going to be a heat loss/cold gain between the cooled or heated fluid in your reservoir and the fermenting beer. I see an average delta between the glycol tank and my fermenter temperature of around 8F. When I'm cold crashing I set the glycol reservoir to 26F to get 34F in the fermenter. So far, no freeze-ups in either the coolant or the fermenter, and I don't see the advantage to try to push things any colder.
 

NewJersey

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Seeing this tilt pro has me pretty annoyed rn.
I use a tilt with the tilt repeater and it would've been nice to just buy this instead.
Oh well.
My tilt works fine btw, but it seems like the repeater isn't working...
 

JoeMamasIPA

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Seeing this tilt pro has me pretty annoyed rn.
I use a tilt with the tilt repeater and it would've been nice to just buy this instead.
Oh well.
My tilt works fine btw, but it seems like the repeater isn't working...
I know we are getting off topic but this is were I am as well. I am debating getting the repeater or the pro. If the pro range is around 20 feet through a stainless fermenter I would consider it. Having said that I typically use the same yeast with a similar grain bill so the fermentation is fairly constant.
 
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Jtvann

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I can test the range if that will help.

All I can say is that it is much better. I leave my old cell phone hanging directly on the fermenter. I’ll pull it away and tear the range though.
 
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Jtvann

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I know we are getting off topic but this is were I am as well. I am debating getting the repeater or the pro. If the pro range is around 20 feet through a stainless fermenter I would consider it. Having said that I typically use the same yeast with a similar grain bill so the fermentation is fairly constant.

That was a fairly easy test. It’s not 20 feet through stainless consistently. I’d say it’s consistent at 10 feet, possibly 15. It is for sure less than 20 feet. I was not able to walk out of the front of my garage without losing signal.

My regular tilt was barely adequate through stainless. It would occasionally lose signal with the phone hanging from the tank. I’d have to reset it once or twice over the whole fermentation window.

I feel like the pro will keep that from happening, and could handle multiple fermenters set up in the same area, but the receiving device needs to be with the fermenters.
 

JoeMamasIPA

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That was a fairly easy test. It’s not 20 feet through stainless consistently. I’d say it’s consistent at 10 feet, possibly 15. It is for sure less than 20 feet. I was not able to walk out of the front of my garage without losing signal.

My regular tilt was barely adequate through stainless. It would occasionally lose signal with the phone hanging from the tank. I’d have to reset it once or twice over the whole fermentation window.

I feel like the pro will keep that from happening, and could handle multiple fermenters set up in the same area, but the receiving device needs to be with the fermenters.
Hey thanks a lot for the test. My experience with the regular TILT is the same; real spotty through the fermenter. Just hard to justify $250 when I can coax a reading out of the regular TILT with some iphone finagling. Thanks again for the follow-up.
 

BigDave1303

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I have noticed that my Tilt temperature takes longer to react (lags behind) the temperature probe on my GF conical. At first I thought it was a fault but now I realise that the Tilt is floating in liquid at the top of the brew whilst the conical probe is connected directly to the stainless surface near the bottom of the brew. The inner workings of the Tilt are within the plastic case, plastic is not a good conductor of heat compared with the directly connected probe in the conical.
The Tilt eventually catches up over time as the brew evens out.
I did do a trial using water and saw the same difference which quickly evened out after a stir. Although I will definitely not be stirring my brew.
I also realise that the SG reading can be a bit unstable during the very active part of the brew however once this has died down it is accurate enough to let you see how the gravity is progressing.
Dry hopping throws the Tilt gravity readings out the window until the pellets start to sink to the bottom.
 
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