Ghetto rigged lagering. Will this work

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fezzman

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I've not yet managed to pick up an external thermostat for lagering in my garage refrigerator. The wife and I are saving for a trip to Bonaire, so I'm on kind of a budget right now. :D

What kind of control do you think I could get by plugging my fridge into a timer? I imagine it would take a bit of tweaking to get it where I would need it. Maybe start by having it turn the fridge on for two hours and off for two. Then adjust it from there to see if I can reach lagering temps.

Do you think this would work or just be a waste of time?
 
Under idea circumstances and a lot of tweaking complete with temperature record keeping, you probably could get by with that. However, there would be a lot of other variables played into that whole scenario as well. Outside ambient temperature? If you have in the garage, there would be a lot of fluctuations that may cause your compressor to turn on more frequently. Humidity is another one. How often would you plan to open and close the door? Like, if your using the refrigerator for other things. One of the first laws in thermodynamics is that heat flows from hot to cold.
 
Have you tried the built in system? Mine seemed to work down to 20f, but I dunno the top end. That's on an old 'frosting' kind. A muffin fan inside from an old computer would keep it consistant. A frostless fridge is more complex though...
 
The warmest I can get it up to is 45F. That's why I figured that if I could just keep the compressor off for a bit longer I could reach the low-mid 50's.

I'm more concerned with just the lager fermenting temps. Can't I just keep it at 45F for the post fermenting?

I don't open the doors on it very frequently because there is nothing important in there, except for a few bottles of homebrew. ;)
 
You should be able to make due with a timer. You need to have the timer come on more in the daytime than the night because it is hotter in the daytime.....so you need a variable delay setting. Otherwise you will get it to 50 during the day and 40 at night.

You can also find the thermostat in your fridge and tilt it to adjust your temp if it's a mercury switch type.
Change resistance of the sensor if it is electronic. Use a volt meter and check the reading that the thermometer sensor is reading @40 degrees and lower it 25% to get the fridge to go to 50 degrees.
 
dougjones31 said:
You should be able to make due with a timer. You need to have the timer come on more in the daytime than the night because it is hotter in the daytime.....so you need a variable delay setting. Otherwise you will get it to 50 during the day and 40 at night.

Ahh, good point. The timer I have can turn off and on each hour, should I choose to. I'll make the daytime cycles longer. I guess I'll start the first experiment tonight and see what temps i can get.
 
I guess I don't understand what you are doing. What will prevent the refrigerator's own thermostat from cycling on and off during your timer cycles? It goes back to my earlier question, is this for fermenting or lagering? Either way, have you determined the max and minimum your refrigerator will hold utilizing its own controls?
 
Brewpastor said:
I guess I don't understand what you are doing. What will prevent the refrigerator's own thermostat from cycling on and off during your timer cycles? It goes back to my earlier question, is this for fermenting or lagering? Either way, have you determined the max and minimum your refrigerator will hold utilizing its own controls?

I was just looking for a way to obtain fermenting temps. Nothing will prevent the refrigerator's thermostat from cycling, except for the timer which will actually shut the whole fridge off.

Isn't that essentially what the Johnson Controls Controller does? Cycle the power to the fridge on/off based on the temp reading from its thermostat? I just thought that a timer could loosely mimic the function of the controller, without its own temp reading of course.

I understand that i likely won't obtain a steady temperature with this method. I am just looking at a way that I can brew a lager this weekend without the need for a controller.

The max temp my refrigerator will do is 45F. I have not tried to see what the minimum temp can be.
 
OK, I get it now. I think you have a good idea and look forward to hearing how it works out. I had a friend who had a light bulb in his as a heat source to keep the temp up in winter time (outside refrigerator).
 
I'm sure it is far from an ideal setup. I'll certainly give it a few days just to see how the temp goes, before actually trying to stick my fermentor in there.

Before I go through the trouble, there isn't a yeast that will ferment at 45F, is there?

That lightbulb idea sounds tempting as well. Hmmmm....it'll definitely be easier to try than my idea.
 
I think the problem is that your fridge, when given power, will always try getting you to your set temp. If your max temp on the built in thermostat is 45, when your timer reapplies power, it's going to start working on dropping it to 45. If I understand your theory, if you time it just right, you'll only give it enough on time to get down to say 55dF. It will be tricky because your outside temp may not be consistent and any tendancy to rise or fall in temp will be somewhat additive so your actual temp may snowball out of your expected range.

I wonder what it would take to modify the temp range of a stock controller. Maybe it's a simple resistor value change? I have no idea what kind of circuits they're based on.

Bobby
 
I really would look at the thermostat in the fridge. If you can alter it then you can maintain a more constant temp.

You just need to see which type of thermostat is there. If it is the mercury switch/coil type then tilting the thermostat a little to one side will give you a little more adjustment in the upper temp ranges
 
dougjones31 said:
I really would look at the thermostat in the fridge. If you can alter it then you can maintain a more constant temp.

You just need to see which type of thermostat is there. If it is the mercury switch/coil type then tilting the thermostat a little to one side will give you a little more adjustment in the upper temp ranges

Not a bad idea at all. Thanks for the tip. Good thing weekend tinker time is nearly here.
 
Oh....make sure you empty the freezer if you have a fridge/freezer combo. Frozen stuff in the freezer will keep you from getting the temps in the fridge up.
 
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