temp deviation

[Minbari]

Prolly discussed before, but here goes

I am an electronics tech by training so getting tight tolerance is in my nature. Is a 2°F swing in your fermentor an acceptable range? I have it set to 68° and the chiller usually overshoots by 0.7° and if heat kicks on it overshoots by the same amount.

The overshoot is caused by residual heat/cold that still has to disapate after the setpoint is reached. Now I could set the SP lower/higher to make it stop early, but the controller I have doesn't have differential setpoints, so one of the operations would still be off

Opions?

 

[Mark Farrall]

I have zero worries about the 1C/2F temperature swings that comes about from using the default setting of the temperature controller I'm using.

If you go to https://brulosophy.com/projects/exbeeriments/ and put fermentation temperature in the search box you can see how hard they have to push temperature changes to get a noticeable difference. Way beyond the 2F that you're considering.

 

[SabreSteve]

There's probably better opinions than mine but unless you're at the very top or bottom of the yeast's ideal range I don't see that small of a variance making much of a difference. Worth noting that many homebrewers have no temp control, or in my case very primative temp control in the form of a cooler and ice bottles

 

[Ward Chillington]

Yeah....a couple degrees here and there... like Tony Soprano says, Faagetta bout et!

From what I know, it's the wild swings in temperature you would need to concern yourself with . If you are working with small volumes of brew, any swings will happen faster so keep that in mind especially during the primary fermentation and like Steve hints to, get in the middle range and you should be just fine..

 

[Minbari]

Cool. Its just the control freak in me. Don't like the control variation.

Ya, i always shoot for middle temp to ferment unless there is reason. I set my glycol chiller for 10° under the SP. Makes a nice gentle correction

 

[HighVoltageMan!]

I’m a electronic tech by training and trade myself. I am also a control freak too. The temperature swings on yeast change from strain to strain. Most ale strains do well being pitched fairly low and allowed to free rise. The rise in temperature is natural due to exothermic activity of the yeast. If the pitch is proper and the wort has been aerated, the swing upward is often a desired result. The yeast will be fine as long as it doesn’t get crazy high.

Don’t fret too much, but if you notice phenolic flavors or the beer seems to taste like it has rocket fuel in it, the yeast probably got too hot. Most times it turns out totally fine

 

[Minbari]

I’m a electronic tech by training and trade myself. I am also a control freak too. The temperature swings on yeast change from strain to strain. Most ale strains do well being pitched fairly low and allowed to free rise. The rise in temperature is natural due to exothermic activity of the yeast. If the pitch is proper and the wort has been aerated, the swing upward is often a desired result. The yeast will be fine as long as it doesn’t get crazy high.

Don’t fret too much, but if you notice phenolic flavors or the beer seems to taste like it has rocket fuel in it, the yeast probably got too hot. Most times it turns out totally fine

Its not getting hot by any means. Literally just that 2° deviation

 

[Nosybear]

Its not getting hot by any means. Literally just that 2° deviation

I'm guessing Inkbird (mine has the same deviation, 0.7° F). Switch it to Celsius - the deviation for Celsius is only 0.3°, slightly less than the Fahrenheit...

 

[Minbari]

I'm guessing Inkbird (mine has the same deviation, 0.7° F). Switch it to Celsius - the deviation for Celsius is only 0.3°, slightly less than the Fahrenheit...

No but similar. The device has a 0.1° acuracy. The temp controller isn't the issue. Its that when the heater or chiller comes on it changes the temp of the beer until it hits the SP. Then turns off. But, the heat or cold is still there until that heat/cold dissipates, it still effects the beer. This causes overshoot.

What I really need is a temp controller with integral/derivative setting, but those are allot more than $30 lol

 

[Nosybear]

No but similar. The device has a 0.1° acuracy. The temp controller isn't the issue. Its that when the heater or chiller comes on it changes the temp of the beer until it hits the SP. Then turns off. But, the heat or cold is still there until that heat/cold dissipates, it still effects the beer. This causes overshoot.

What I really need is a temp controller with integral/derivative setting, but those are allot more than $30 lol

A PUD controlled fridge... It's good that the variation is greater within the fermentor during fermentation than the variation due to temperature yo-yoing

 

[GFHomebrew]

You know your temp probe could be out by that much lol. Sorry had to mention it I'm imagining you going and testing the probe against your best thermometer now. Hope that's accurate too!

STC allow you .3c degree swing if you want which is what I use I set the swing to .5c

Probe placement is another thing I just strap mine to the side of the fermentor with a stubbie cooler on the outside.

Good luck I'm sure with your OCD you'd make some fine beer.

 

[Minbari]

All valid points lol

So just to compete my neuroses. I designed and built a companion board for the temp controller on the heat side. (See below) It allows full heat for 30 secs and then cuts it back to 25% until the SP is hit. This slows the heating cycle down considerably.
Just as an experiment instead of 1° deviation on the controller I changed it to 0.2°. Now before you call me crazy, the idea was if the heat/chiller are on for a shorter duration then the residual heat/cold will be less since they have less time on. It seems to have worked. My temp swing went from 2° to about 0.6°

 

[Donoroto]

If you're crazy, then most of are too.

As everyone noted, 2 degrees overshoot is nothing to worry about. 200 years ago they had nothing of the sort. Many of my fermentations are in free air, and I can see 6 F fluctuations at times.

Also an electronics guy, the limiting factor in your poor-man's PID is sensing temperature. As @Trialben mentioned, your sensor could be off a bit, but think about what exactly you are sensing: The center of the wort? (Then what about the edges?) The top of the wort? (What about the bottom?) The outside of the fermenter? You get it.

Sense what you need to control, but make sure you're really sensing it. Then you can implement a true PID control, fine-tuning P, I and D for your needs. I could talk all day about PID, so if you have questions...

 

[Minbari]

If you're crazy, then most of are too.

As everyone noted, 2 degrees overshoot is nothing taboub worry about. 200 years ago they had nothing of the sort. Many of my fermentations are in free air, and I can see 6 F fluctuations at times.

Also an electronics guy, the limiting factor in your poor-man's PID is sensing temperature. As @Trialben mentioned, your sensor could be off a bit, but think about what exactly you are sensing: The center of the wort? (Then what about the edges?) The top of the wort? (What about the bottom?) The outside of the fermenter? You get it.

Sense what you need to control, but make sure you're really sensing it. Then you can implement a true PID control, fine-tuning P, I and D for your needs. I could talk all day about PID, so if you have questions...

Oh ya, i understand. Temp difference at the top vs bottom of the fermentor is about 3° lol. So this is realbly less about the beer and more about me accomplishing a something that I wanted to (even ifit makes zero
difference) i have calibrated the sensor to a stick thermometer, so at least that is reasonablely accurate at this temp range

Also I used to work for company that did thermal testing with industrial ovens. So some of my OCD cones from having equitpment that could zero in on a temp to with in 0.1°.

 

[Craigerrr]

When you are measuring the temperature in the center of the fermenter, and either cooling or heating from the exterior, the temperature fluctuation within a degree or two is unavoidable. More to do with physics than electronics. While am sure more precise control is achievable, it really isn't necessary, or worth the cost involved.

Think of it this way.
Yeast are living organisms and are use to temperature swings, otherwise they would not survive. Much like the way we heat our homes, there are temperature swings, and it is warmer at the ceiling, and cooler at the floor, but we are within our comfort range.

I think that this is a RDWHAHB moment

Cheers!

 

[Minbari]

When you are measuring the temperature in the center of the fermenter, and either cooling or heating from the exterior, the temperature fluctuation within a degree or two is unavoidable. More to do with physics than electronics. While am sure more precise control is achievable, it really isn't necessary, or worth the cost involved.

Think of it this way.
Yeast are living organisms and are use to temperature swings, otherwise they would not survive. Much like the way we heat our homes, there are temperature swings, and it is warmer at the ceiling, and cooler at the floor, but we are within our comfort range.

I think that this is a RDWHAHB moment

Cheers!

RDWHAHB?

Ya I don't disagree. But I like to tinker, I WILL win! Lol

The heating and cooling is internal as well. Not sure that changes your point

 

[Craigerrr]

RDWHAHB = Relax, Don't Worry, Have a Homebrew!

If you are heating and coming internally via, I assume a coil, your temperature control will be more finite than my old fridge, and space heater fermenter setup. I have never had a complaint (off flavor) from any of my yeast buddies!

 

[west1m]

Gee a lot of control folks here. I spent the last twenty-five years boiling dinosaurs to make gasoline etc. I controlled my processes in one degree or less increments. My home oven swings twenty five degrees ,think that doesn't bug me?

 

[Minbari]

Gee a lot of control folks here. I spent the last twenty-five years boiling dinosaurs to make gasoline etc. I controlled my processes in one degree or less increments. My home oven swings twenty five degrees ,think that doesn't bug me?

Exactly!

 

[Megary]

I did a side by side test in a glass of tap water today after I noticed my normal digital thermometer (white) bouncing around a bit while taking a couple of readings. That’s not acceptable for measuring mash temps so in the trash it went.