Keezer, stc query

[Ghizo]

I have just been given a 210l chesty, I am looking at either changing the thermostat (seen kits on eBay anyone used one of these?). Or buy another stc 1000 to control it.
If I go the stc way where am I best to mount the probe? I have seen them put in jug of water as well as mounted in the middle of the freezer?

Which is the best way to go?

 

[nosco]

I put mone in a 2lt bottle of water. It over shoots a little some times but i get aboit .5c le way.

 

[TheWiggman]

If you can get a small bit of aluminium, say 25x50, and fix the sensor to it. Use a bit of thermal paste between the sensor and strip. Stick this to the side of the keeper and you'll be cheering.

 

[Ghizo]

Is the sensor ok to be in water?

 

[Pogierob]

What you are trying to achieve is the fermentation temperature, so the most accurate reading is going to come from a probe that is either IN the beer or reading the internal temperature through a thermowell.

this then comes down to what type of fermenter you are using, if you are using a glass carboy then a thermowell is not an option, however dangling a probe into the beer is, however the standard probe that comes with the STC isn't really suitable for this and I would suggest getting a stainless steel probe such as in the link http://www.fullpint.com.au/ntc-20cm-temperature-probe/

These are designed I believe to fit into a thermowell if you wanted to go that path also.


The 2lt bottle of water with probe trick probably works reasonably well however there are a few factors to consider.

The 2lt bottle of water isn't fermenting so you are not measuring the heat created by fermentation.
2lt of water will adjust temperature quicker than 20lt of beer.


I personally used to just have the probe either hanging in the chamber measuring ambient temperature and then I did the old stubby holder taped to the side of the fermenter tricks.

As mentioned earlier neither of these methods were measuring the internal fermentation temp. (I worked out that 16 deg on the STC gave me close to 18 deg fermentation) but this may vary from each persons equipment.

It was shitting me that I couldn't give a definitive answer in relation to my fermentation temp control so now I have a SS probe that dangles into the centre of my plastic fermenter and I used the old glad wrap lid method.


I guess you just have to ask yourself how accurate you want to be and then base your equipment on that decision. with the Freezer already sorted, it's not a big investment to go that little extra step to get the most accurate control you can.

 

[Ghizo]

Not for a fermentation sorry rob keezer,

 

[Pogierob]

Ahh oops, then forget everything I just said. Carry on

 

[Moad]

I have a stubby of water with a probe in it on the compressor hump. Thinking about it the bottom might be cooler but only a degree tops. Get a fan in there to keep the air moving

 

[mofox1]

Easy peasy.

STC-1000. Sensor duct taped to the side of the freezer wall with a small piece of foam between it and the freezer wall to monitor the freezer air temp a bit more accurately (not affected by cooling coils on other side of freezer wall).

+1 to the fan idea. Will be implementing that as part of the collar build.

 

[spog]

I have a stubby of water with a probe in it on the compressor hump. Thinking about it the bottom might be cooler but only a degree tops. Get a fan in there to keep the air moving

Hmm, and the probe is telling you the temp of the stubby of water,not the beer nor the keezer.
A probe ( temp) some where in the keezer ,not wrapped or shrouded in anything will give the best indication of keezer temp.
The beer temp is another matter and the only way to find this is to measure it,but in a keezer given a couple of days the difference would be bugger all if anything at all.

 

[osprey brewday]

Probe in the water will prevent short cycling of compressor which would already be short cycling given it would normally have had a 5deg or so differential as a freezer much better for life span of the compressor if probe is in a thermal mass. Tablet bottle/container filled with candle wax with probe in centre works well or just water in a bottle.Have used an apple before also good for about 2 months

 

[Crusty]

Hmm, and the probe is telling you the temp of the stubby of water,not the beer nor the keezer.
A probe ( temp) some where in the keezer ,not wrapped or shrouded in anything will give the best indication of keezer temp.
The beer temp is another matter and the only way to find this is to measure it,but in a keezer given a couple of days the difference would be bugger all if anything at all.

Just having the probe hanging about in the keezer is a bad idea. Even with a fan for air circulation the compressor will be on & off far too often as osprey brewday suggested. We don't want to know the air temperature in the keezer, we want to know the temp of the liquid that's in there. I've tried it several ways & the most accurate is the way Moad suggested & it's exactly what I'm doing. The probe on the STC is also fine too immerse in water. I haven't got a clue what the actual air temp is in there but I know the stubby of water & the beer is sitting at 3deg.

 

[Moad]

Yep I figured in liquid was not going to be 100% accurate but more so than hanging in the air.

We are talking very minor temp differences between the water and the beer which I'm ok with. I trust it will sort itself out over time.

 

[TheWiggman]

Here's what I was getting at, which is pictured from a Jaycar temp control kit -

 

[jeremy]

Just having the probe hanging about in the keezer is a bad idea. Even with a fan for air circulation the compressor will be on & off far too often as osprey brewday suggested. We don't want to know the air temperature in the keezer, we want to know the temp of the liquid that's in there. I've tried it several ways & the most accurate is the way Moad suggested & it's exactly what I'm doing. The probe on the STC is also fine too immerse in water. I haven't got a clue what the actual air temp is in there but I know the stubby of water & the beer is sitting at 3deg.

I know a lot of people subscribe to this theory but it just seems wrong to me. The liquid in the freezer will eventually stabilize to the same temperature as the ambient temperature in the freezer (given that it is not fermenting). As such I think you need the air temperature to be measured and controlled. Fair enough if you are worried about the constant cycling of the power on and off, with my Tempmate this is dealt with by setting an on value and an off value, and I believe it even has a minimum time between as an extra backup (which I dont think would even be required if the difference between the temps is >2 deg), perhaps the STC does not have this feature. However I think even a stubby of water is too much insulation for the probe. If you put the stubby of water if the freezer I would think that by the time it gets down to 2deg, the freezer will be at minus 10, by the time the stubby returns to 4 degrees the freezer will be at 15. I think you want the ambient temp swinging 2-3 deg, and the liquid temp will struggle to swing by a single degree.

Obviously plenty people are operating well on this model, so it must work on some level, but I have a probe just hanging 4 inches from the lid of my freezer, with no fan circulation at all, and the temp set on 2, and its been going strong for many years, temperatures perfect all year round. I think if you are fiddling around with a stubby of water and you have never tried just letting your probe swing in the breeze (or tape it to a bit of foam on the side of the freezer) its definitely worth giving it a shot, especially if you are having issues controlling your temps.

 

[mofox1]

Yep STC has that option... F3 I think. Can set the compressor delay from 1 to 10 minutes.

You can also set the hysteresis (F2) to a largish value too - ie allow a temp diff of whole degree or two. I'm not *that* picky about the exact temp of my beer to have it controlled to the micro-degree. I like it cold, but not too cold you cant taste it. I do tend to adjust the temp for what I'm serving, but anywhere between 4 and 8 seems to do the job... I'm not the OP, but I assume I would be happy setting it 5 deg, with a hysteresis of 2 degrees, so once it warms up to 7 it will cool it back down to 5.

I might check my settings tonight...

 

[spog]

I know a lot of people subscribe to this theory but it just seems wrong to me. The liquid in the freezer will eventually stabilize to the same temperature as the ambient temperature in the freezer (given that it is not fermenting). As such I think you need the air temperature to be measured and controlled. Fair enough if you are worried about the constant cycling of the power on and off, with my Tempmate this is dealt with by setting an on value and an off value, and I believe it even has a minimum time between as an extra backup (which I dont think would even be required if the difference between the temps is >2 deg), perhaps the STC does not have this feature. However I think even a stubby of water is too much insulation for the probe. If you put the stubby of water if the freezer I would think that by the time it gets down to 2deg, the freezer will be at minus 10, by the time the stubby returns to 4 degrees the freezer will be at 15. I think you want the ambient temp swinging 2-3 deg, and the liquid temp will struggle to swing by a single degree.

Obviously plenty people are operating well on this model, so it must work on some level, but I have a probe just hanging 4 inches from the lid of my freezer, with no fan circulation at all, and the temp set on 2, and its been going strong for many years, temperatures perfect all year round. I think if you are fiddling around with a stubby of water and you have never tried just letting your probe swing in the breeze (or tape it to a bit of foam on the side of the freezer) its definitely worth giving it a shot, especially if you are having issues controlling your temps.

Hmm, maybe I was on the right path with my post,or maybe not .only time will tell,sounds like a good dedicated topic .

 

[kennek]

Have a keezer around the same size. And have the stc probe in a bottle of water. Works just fine.

 

[yum beer]

I use an upright freezer as bottle fridge, STC in a stubby of water in front left corner set to 1.8c keeps everything cold and lagers what needs lagering.
I have a separate probe measuring air temp, it can jump up to mid teens when I have door open to retrieve a bottle of golden refreshment, beer in bottles is still 1.8c and the freezer temp drops back pretty quickly with the thermal mass inside. Compressor does not start and 10 minutes later temp is back to 1.9c, takes hours to climb to 2.3c(switching temp). If I was going off the hanging sensor the freezer would by kicking in and out like a *******. The beer inside whether bottled or kegged is going to take a long time at lower or elevated temps before making any noticeable difference.
Probe has been in stubby for around 2 years now with no issues.

 

[ahferg]

This is what I used on my Keezer and it works perfectly.