temp control help.

I swear its like ive asked to many questions in the past week. Hopefully im not annoying with the questions. But i have another one.

Bought this temp control (http://www.northernbrewer.com/shop/...on-controls-a419-digital-temp-controller.html)

however my chest freezer is already at around 40-50F so it's a little to cold for what im brewing according to the instructions. I also have a cold cellar in my basement, would i just hook up my temp control to a lightbulb in the freezer to heat it up when needed or a area heater in the cellar (perhaps when i have several fermentations)?

Thanks in advanced

Tape the "probe" to the carboy/bucket to with some foam. You want the temp of the wort not the air.
Then set the Temp control to the temp range of the yeast your using.
So, if you want to ferment at 65F.. set it there. and it will stop cooling.

The way those temp controllers will work is that when it gets near the top of that temperature range, it'll turn the freezer on. When it cools off to go near the bottom of that range, it'll turn the freezer off, allowing it to warm back up naturally, until it gets too warm, and the whole cycle starts over.

bfinleyui said:

The way those temp controllers will work is that when it gets near the top of that temperature range, it'll turn the freezer on. When it cools off to go near the bottom of that range, it'll turn the freezer off, allowing it to warm back up naturally, until it gets too warm, and the whole cycle starts over.

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Ya but the freezer is already to cold, so do i have to have a bulb or heater in the on 24/7? there must be a more efficient way of doing this

This is the problem I had over the weekend. I put a string of C9 Christmas lights with all but one bulb removed in refrigerator drawer. It puts off just enough heat that the compressor and the heat source aren't competing with each other too hard. In other words the cycling is kept to a very reasonable rate.

gromitdj said:

This is the problem I had over the weekend. I put a string of C9 Christmas lights with all but one bulb removed in refrigerator drawer. It puts off just enough heat that the compressor and the heat source aren't competing with each other too hard. In other words the cycling is kept to a very reasonable rate.

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thank you! ill be testing out bulb sizes

drewN said:

Ya but the freezer is already to cold, so do i have to have a bulb or heater in the on 24/7? there must be a more efficient way of doing this

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I think you are missing the point, the controller will shut your freezer off, and only turn it on when and only for how long, it takes to cool your beer.
Unless your freezer stays too cold with it unplugged this will work.
Ie... if your freezer is outside in winter you will need heat but otherwise not.

The controller controls the power to the freezer. They switch on and off the plug that they plug into. This will keep the freezer from getting too cold. Additionally if you have a 2 stage controller, you could include a heat source (light bulb, fermbelt, etc) on the other side to keep it from getting too cold if the freezer is in a colder than desired area.

menerdari said:

I think you are missing the point, the controller will shut your freezer off, and only turn it on when and only for how long, it takes to cool your beer.
Unless your freezer stays too cold with it unplugged this will work.
Ie... if your freezer is outside in winter you will need heat but otherwise not.

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I understand what the OP is saying, its basically that its already to cold to do the beer he wants too..

Dont fiddle with lights, if you need to warm it up just give it time..open the lid and blow the cold air out of the bottom with a fan and give it 4 hours for the walls to warm up.

Then plug it into your temp controller, and it will pull it down to the 60-65F or whatever you have it set to for fermentation.

menerdari said:

I think you are missing the point, the controller will shut your freezer off, and only turn it on when and only for how long, it takes to cool your beer.
Unless your freezer stays too cold with it unplugged this will work.
Ie... if your freezer is outside in winter you will need heat but otherwise not.

Click to expand...

I understand what the OP is saying, its basically that its already to cold to do the beer he wants too..

Dont fiddle with lights, if you need to warm it up just give it time..open the lid and blow the cold air out of the bottom with a fan and give it 4 hours for the walls to warm up. Or just unplug it and open the lid up and leave it open for a while.

Then plug it into your temp controller, and it will pull it down to the 60-65F or whatever you have it set to for fermentation.

Ya the freezer isn't plugged in and it's to cold is what im trying to say. Sorry for the confusion. Thats why i think have a low energy light with the lid closed + temp control might work best for me

drewN said:

Ya the freezer isn't plugged in and it's to cold is what im trying to say. Sorry for the confusion. Thats why i think have a low energy light with the lid closed + temp control might work best for me

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Gotcha, i had it in reverse,keep forgetting its winter.

Get a reptile warming light thing from any pet store. They work really well ive heard. They produce lower heat then a standard bulb, so you arent likely to overshoot your temperatures as harshly as if you just stuck a standard 100W bulb or something in there. And atleast in my mind, less chance of a fire or something...you are sticking a bulb in a very very small space that is designed to keep the heat in...standard bulbs can heat those areas up super fast as you likely know...as most dudes have stuck their hands up next to a lit light bulb at some point in their life and gotten burned lol.

brew a lager

drewN said:

Ya the freezer isn't plugged in and it's to cold is what im trying to say. Sorry for the confusion. Thats why i think have a low energy light with the lid closed + temp control might work best for me

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You can use a simple heating pad an just hang it in your freezer, works great for me.

When summertime rolls around, you may still have the same issue. I have the Johnson II as well. And I think bc my freezer isn't very efficient, it was over cooling. Had the set point at 70 with a diff of 1. So the freezer would kick on when it hit 70, then stay on til my probe (insulated and taped to fermenter) hit 69. But the freezer took so long to drop my fermenter 1 degree that the air temp actually dropped to 55. So while the freezer was off, my fermenter actually dropped down to 60 before it started heating up again. Anyhow, you may not have this issue in the summer as a lot of people do not. But if you do, you will need to look at a dual controller that has the option for a heating element and cooling element to run simultaneously. I now have a ranco dual controller, works amazing in winter and summer. It also works well for those days when the high is 75 and low is 40 (freezer is in the garage). Keep this in mind.

The heating pad is what I use and it works for me.

Where are you guys getting these heating pads?

drewN said:

Where are you guys getting these heating pads?

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Just a simple like 12 inch by 12 inch heating pad people use on their back or body. Cvs has them, grocery stores probably have them.

Double-R said:

Tape the "probe" to the carboy/bucket to with some foam. You want the temp of the wort not the air.

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I don't mean to open a can of worms here but it is better to put the probe in the open air of the freezer and a thermometer either in the wort or on the carboy/bucket. Change the temp of your controller while watching the temp of your wort and adjust accordingly. The thermal capacitance of wort is ginormous compared to air so your freezer will have to make huge temp swings to maintain the wort within the temperature range targeted by your controller. Most temp controllers work within a few degree differential too so the freezer may not turn on until your wort is a couple degrees over your target then the coolant may run through the coils for a bit once the compressor turns off potentially overshooting your target the other way. If you put the controller probe in the air, you are allowing the freezer to make its usual 5-10 degree swings while your wort only changes a half a degree. Granted, this all takes a little extra babysitting in the first few days of a heavy fermentation and your freezer will run for shorter periods more often but it is ultimately more accurate and more consistent.

Valid point, makes sense to me. Would have definitely solved my issue of overcooling with the Johnson II controller. Have you found if there is a common air temp that works for all wort? Or do you usually figure out your set point batch by batch? Do you have a simple process of figuring out a good set point other than just posting up with some homebrew and watching the controller and the thermometer

I've also heard that the temp of the middle of the wort can be a few degrees different than the edges. But on the other hand I've read that due to some law of physics the temp of the wort will be the same throughout the wort because it heats and cools together? Can anyone clarify this?

carsonwarstler said:

Have you found if there is a common air temp that works for all wort? Or do you usually figure out your set point batch by batch? Do you have a simple process of figuring out a good set point other than just posting up with some homebrew and watching the controller and the thermometer

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It varies throughout the fermentation. For the first couple days you may need to set it a few degrees below your target to compensate for the heat produced by the fermenting wort. Once that's passed, maybe a degree above your target or right at it. I'll usually let the temperature gradually rise once things have settled down so I adjust it fairly regularly. I have a web based logging/control system going though, so I have the advantage of being able to keep an eye on it from work.

carsonwarstler said:

But on the other hand I've read that due to some law of physics the temp of the wort will be the same throughout the wort because it heats and cools together? Can anyone clarify this?

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Convection. Warmer wort will rise on the outside of the vessel then fall on the inside when it cools at the top. This may cause the outside to be a hair warmer than the inside but for the most part it should all be fairly even. This only really occurs when the wort is actively fermenting.

Spintab said:

It varies throughout the fermentation. For the first couple days you may need to set it a few degrees below your target to compensate for the heat produced by the fermenting wort. Once that's passed, maybe a degree above your target or right at it. I'll usually let the temperature gradually rise once things have settled down so I adjust it fairly regularly. I have a web based logging/control system going though, so I have the advantage of being able to keep an eye on it from work.

Convection. Warmer wort will rise on the outside of the vessel then fall on the inside when it cools at the top. This may cause the outside to be a hair warmer than the inside but for the most part it should all be fairly even. This only really occurs when the wort is actively fermenting.

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Great to know. Thanks for the info. For now, I'll probably have to stick to my dual controller with the probe insulated on the fermenter because I won't have quick access to monitor and change it throughout the day. I've been able to keep it between a 3 degree range, so I feel it's sufficient for now.

Spintab said:

It varies throughout the fermentation. For the first couple days you may need to set it a few degrees below your target to compensate for the heat produced by the fermenting wort. Once that's passed, maybe a degree above your target or right at it. I'll usually let the temperature gradually rise once things have settled down so I adjust it fairly regularly. I have a web based logging/control system going though, so I have the advantage of being able to keep an eye on it from work.

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I gotta raise my hand in confusion. What does yeasties copulating have to do with your target temperature? Target temperature is target temperature, right? It is what you are shooting for to correct all the ancillary influences.

Spintab said:

Convection. Warmer wort will rise on the outside of the vessel then fall on the inside when it cools at the top. This may cause the outside to be a hair warmer than the inside but for the most part it should all be fairly even. This only really occurs when the wort is actively fermenting.

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Trying to understand this here. I'm used to warm rises, cool falls. Now, within a vessel, outside rises and interior falls? Aren't the yeasties equally distributed throughout the vessel, why does the exterior behave differently from the interior?

MrNatural said:

I gotta raise my hand in confusion. What does yeasties copulating have to do with your target temperature? Target temperature is target temperature, right? It is what you are shooting for to correct all the ancillary influences.

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When the yeast are actively fermenting, they produce heat. Enough for the wort to be a handful of degrees warmer than the air around it. I control the air temperature around the wort when I ferment so I set my controller to target air temps lower than my targeted wort temp to compensate for the extra heat.

MrNatural said:

Trying to understand this here. I'm used to warm rises, cool falls. Now, within a vessel, outside rises and interior falls? Aren't the yeasties equally distributed throughout the vessel, why does the exterior behave differently from the interior?

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There is a ton of awesome science happening when fermentation is really going. I don't know it all spot on but there are a number of things going on. First, the heat. While the yeast is in fact distributed throughout the vessel, you will still get portions that rise from the heat produced then cool when they reach the top. Second, co2. We all know co2 is a byproduct of fermentation. It has to get out of the wort somehow. Up and it most likely brings some wort along for the ride. Last, alcohol. As the wort ferments, it gets lighter. I would think this would cause a little motion but it happens so slow I don't know how much.

I really wish I fermented in carboys because this whole process is really cool to watch. There are a bunch of youtube videos out there.

MrNatural said:

Trying to understand this here. I'm used to warm rises, cool falls. Now, within a vessel, outside rises and interior falls? Aren't the yeasties equally distributed throughout the vessel, why does the exterior behave differently from the interior?

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Probably way off but this is what springs to mind for me:fro:

Bit like wind or sea currents, maybe? The path of least resistance and also opposites attracting. The warmer liquid will find less resistance, and be attracted towards the cooler temps, at the outer surfaces of the fermenter. After cooling it'll be heavier than the rest of the wort and so sinking into the centre is possible. Then the movement from convection is perpetuated until fuel, sugar for the yeast, is depleted.