Keeping exact temperature control during fermentation

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Newtybar

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Hi All,

I currently have a chest freezer along with a digital temperature controller. However is there a better way of keeping the temperature consistent? I know certain yeast will end up tasting different if fermented at 68 degrees versus 72 degrees...but it seems like my setup fluctuates quite a bit between that range.

When it is too hot the controller turns on the freezer which in turn cools it rapidly...sometimes down to 60 degrees before it shuts off.

Also in the winter I plan on getting a heating device...but what if there's a heat wave in the winter which takes temperatures up to 80 degrees?

Is there some sort of combo device that heats and cools, keeping the temps exactly at 72 degrees?
 
From your setup you might want to try using a thermowell in the airlock and using a heat pad

Place the fermentor in the cold fridge with the heat pad wrapped around the carboy. Let the controller turn on and off the heat pad.


Sent from my iPhone using Home Brew
 
I know alot of people will tape the probe to the side of the carboy and then tape insulation over the top of that. I personally let the probe measure ambient temp in the freezer, and keep the Setpoint set @ 62F for ales or 46F for lagers and pitch at the lower end of the temp spectrum. So far it has worked well without issues
 
My probe is just in the freezer about halfway down, recording the ambient temp.

Interesting idea on the heatpad freezer combo. I was thinking one controller for the heatpad and another for the freezer. Gets too hot, the freezer activates...gets too cold, the heatpad activates.
 
Newtybar said:
When it is too hot the controller turns on the freezer which in turn cools it rapidly...sometimes down to 60 degrees before it shuts off.
Click to expand...

To me it sounds like you might have an issue with the settings on your temp controller, such as allowable variance or something. When set up properly, you should not get swings of more than a few degrees.

Edit: or it may be because you are measuring air temp and not beer temp. Air temp fluctuates MUCH faster than beer temp.

Newtybar said:
My probe is just in the freezer about halfway down, recording the ambient temp.
Click to expand...

Natdavis777 said:
I personally let the probe measure ambient temp in the freezer
Click to expand...

Ambient temp does not equal beer temp. There can be a huge difference between the two during active fermentation. It also results in the freezer cycling much more frequently, as the ambient temp will fluctuate MUCH more readily than the liquid temp will, which is hard on the compressor. I would strongly suggest finding a way to measure beer temp, be it via a thermowell or simply attaching the probe to the side of the fermenter.
 
hunter_la5 said:
To me it sounds like you might have an issue with the settings on your temp controller, such as allowable variance or something. When set up properly, you should not get swings of more than a few degrees.

Edit: or it may be because you are measuring air temp and not beer temp. Air temp fluctuates MUCH faster than beer temp.





Ambient temp does not equal beer temp. There can be a huge difference between the two during active fermentation. It also results in the freezer cycling much more frequently, as the ambient temp will fluctuate MUCH more readily than the liquid temp will, which is hard on the compressor. I would strongly suggest finding a way to measure beer temp, be it via a thermowell or simply attaching the probe to the side of the fermenter.
Click to expand...


I am aware ambient temp doesn't equal beer temp. I have experimented with this method by measuring the temp of the wort during fermentation and the technique I am utilizing now has always kept me within a few degrees of what I am aiming for. It works for me and I don't have to spend money on thermowells.


Sent from my iPhone using Home Brew
 
I use a STC-1000 to control my freezer. The probe is in a stainless steel rod submerged in the beer. The stc also runs a heating pad to warm it if needed. It is pretty accurate. I also have another thermometer to measure the ambient temp in the freezer. While the ambient temp will fluctuate from 60-70 degrees the beer only fluctuates a degree or two. Which I think is perfectly acceptable. Here is a link to the thermowell I use. That is the set up I have been most satisfied with.
 
I too use a freezer and set the temp controller at 60 (I use WLP090 for the most part). I have done many batches this way and the ambient will keep my beer for the most part at 63-64 which is exactly where I want it. After 4 days I start raising it one degree a day until I am at 67 and let it sit for another week. This has created beers with no off flavors. The freezer runs maybe 6-8 times a day and only runs for a minute or two.
 
If you put a fan in your chamber it will certainly help. With stagnant air you could have very different temperatures througout your chamber. Get the air moving around and you will see much better results. It will cause your compressor to cylce more often though which to some is too much of a downside. I don't mind it.
 
thisisbeer said:
I use a STC-1000 to control my freezer. The probe is in a stainless steel rod submerged in the beer. The stc also runs a heating pad to warm it if needed. It is pretty accurate. I also have another thermometer to measure the ambient temp in the freezer. While the ambient temp will fluctuate from 60-70 degrees the beer only fluctuates a degree or two. Which I think is perfectly acceptable. Here is a link to the thermowell I use. That is the set up I have been most satisfied with.
Click to expand...

How do you run the heating pad and freezer at the same time with the STC?
 
Newtybar said:
How do you run the heating pad and freezer at the same time with the STC?
Click to expand...

The STC-1000 is a two stage controller. So when it gets too warm, the freezer will come on, and if it overshoots and gets too cold, then the freezer shuts off and your heater turns on. Far better than a single-stage controller and very well suited for thermowell use.
 
This is great guys, both the link to the blackbox and description of what the STC does is great.

Extremely helpful!
 
Sorry, I had an additional thought about the heat pad.

The outer liquid will be much warmer than the inner liquid inside the carboy. Will this be an issue?
 
What everybody else said. The heat seems to rise up quickly through the carboy. I have never had an issue with it during active fermentation. Thats when the temp counts.
 
If you don't want to put your thermometer in the beer you can put it inside a hydrometer tube filled with water. Water heats and cools much slower than ambient air temp.
 
Like someone else mentioned about the settings on the STC for allowable tolerance. I believe it is the F2 or F3 value. If it is set for too large of a spread it will cool/heat within the set value. I.e. If you want 65f and the F value on the controller is at 10, it will have a 10 degree window on either side of 65 (55/75).
 
zoomzilla said:
If you don't want to put your thermometer in the beer you can put it inside a hydrometer tube filled with water. Water heats and cools much slower than ambient air temp.
Click to expand...

There's really no reason to ever put the probe in a flask of water or whatever if your controller lets you set the differential. All you're doing by putting the probe in a glass of water is increasing the differential. Instead of messing with a glass of water, just follow the rule: if the probe is in the beer, use a 0.5F diff; if it's in air, use a 3-4F diff. Either will roughly accomplish the same thing.
 
SpeedYellow said:
There's really no reason to ever put the probe in a flask of water or whatever if your controller lets you set the differential. All you're doing by putting the probe in a glass of water is increasing the differential. Instead of messing with a glass of water, just follow the rule: if the probe is in the beer, use a 0.5F diff; if it's in air, use a 3-4F diff. Either will roughly accomplish the same thing.
Click to expand...

^^^ what he said. I use 0.5 degree on my probe in the beer.
 

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