# temp probe outside or in fermenter?



## kiwisteveo (17/8/14)

Just brought a keg king 16amp temp controller and was wondering what do most people do and or is the best

a) tape probe to outside of fermenter,
b) insert probe through fermenter using a plastic bulkhead,
c) insert probe through fermenter using stainless thermowell,
d) insert probe through lid of fermenter into wort,

fermenter will be in a dead fridge using a heat belt,

cheers kiwisteveo


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## Diggs (17/8/14)

Taped to the outside, but open to better ways to use it.


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## growler (17/8/14)

I use a block of styrofoam, (with a groove for the probe on the inside) taped to the fermenter about midway down. You just need to wipe the outside of the fermenter before taping to get a good "stick" with the tape.

G.


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## BrosysBrews (17/8/14)

I have mine on the outside, but I use a stainless fermenter so I believe the temp conduction would be better then if you are using plastic, see link for picture.

http://aussiehomebrewer.com/topic/79589-temp-control-set-up/

Also I have it insulated using some polystirine


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## CrookedFingers (17/8/14)

I use a SS fermenter, keg king temp controller also.
Fitted a SS thermowell. 
I figure I wanted the probe right in there....nice and deep like .....hmmm






CF


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## zooesk (17/8/14)

I use the foam too but I have a shoelace with both ends tied to an elastic band stops messing around with tape


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## pcmfisher (18/8/14)

If you use a dead fridge even without a heater belt your beer is going to get real hot real fast at the beginning of your ferment as the heat generated by the yeast will not be able to escape.
Something to watch.


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## brewologist (18/8/14)

I use an old neoprene stubby holder that is cut up, then doubled over, and gaffa taped to the side of the fermenter. This is to insulate the probe from the ambient temp in the fermenting freezer.


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## mofox1 (18/8/14)

^What they said.

Taped polystyrene. Might even upgrade to an ocky strap one day.


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## TidalPete (18/8/14)

In the process of getting home-made thermowells welded to ss lids for ss fermenters but until then put probe on the outside as in the pic.


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## pilgrimspiss (18/8/14)

brewologist said:


> I use an old neoprene stubby holder that is cut up, then doubled over, and gaffa taped to the side of the fermenter. This is to insulate the probe from the ambient temp in the fermenting freezer.


 Same here....half a stubby holder taped to side with temp tape, insert temp probe.

Ale: 12V pc fan sitting on a piece of PVC pipe for recirc air, heat pad and fridge plugged into STC1000. Keeps temp at 18C
Using 60 litre fermentors now so the head pad sits in the door.


Lager: Fridge controller set to 13C with fridge plugged in, also has fan in door for recirc air.





Cheers
Matty


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## Spiesy (18/8/14)

Option 'C' for me. Stainless thermowell gets the probe right into the middle of the wort for a super-accurate reading. Easy and cheap enough to do.


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## Dan Pratt (18/8/14)

Mine is mounted to the outside with 2 x ockey straps and a piece of stubbie holder


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## Exile (18/8/14)

Mines a 12" Weldless Thermowell mounted from the lid to get that deep penetration


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## Blind Dog (18/8/14)

Strapped to the outside covered in a cut up old mouse mat.

Upgrading to SS fermenter, hopefully this weekend, and aim to add a SS thermowell through the lid


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## Diggs (18/8/14)

I am definitely "upgrading" to include old stubby holder.


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## Mattress (18/8/14)

My observations

I used to use the cut up stubby holder taped to the outside method

upgraded to a beerbelly thermo well and was surprised in the difference in temp, especially noticeable when first cooling the wort down to pitching temps.
I was getting a reading at least 2 degrees warmer with the thermo well.
It also takes a lot longer for changes to the fermenter temperature to occur with the thermo well, taking the reading from the middle of the wort.


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## panzerd18 (18/8/14)

Spiesy said:


> Option 'C' for me. Stainless thermowell gets the probe right into the middle of the wort for a super-accurate reading. Easy and cheap enough to do.


How much difference in temperature does this make compared to reading the temperature on the outside surface of the fermentor thats been insulated with foam?


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## superjim (18/8/14)

panzerd18 said:


> How much difference in temperature does this make compared to reading the temperature on the outside surface of the fermentor thats been insulated with foam?


For me, I found it was about 2-3 degrees, like Mattress said.

A blind stainless tube directly into the wort will obviously have a better reading, and sanitary issues are pretty much non-existent if you follow normal procedures. I'll upload some pics later but I use electrical cable glands, fairly cheap and easy to clean.

That said, if you know your process and you know what "artifacts" fermenting at the temperature your external probe with your foam/abandoned stubby holder produces, there's nothing wrong with that. As long as the process is repeatable and consistent.


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## Coalminer (19/8/14)

I am having good control with this through the fermenter lid connected to an STC1000

http://www.craftbrewer.com.au/shop/details.asp?PID=955


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## vykuza (19/8/14)

Spiesy said:


> Option 'C' for me. Stainless thermowell gets the probe right into the middle of the wort for a super-accurate reading. Easy and cheap enough to do.



This is what I do as well. Just put a stainless thermowell through the side wall of my bunnings fermenter. Takes about 5 minutes to do, and that includes the time getting the drill out of the shed.


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## Spiesy (19/8/14)

panzerd18 said:


> How much difference in temperature does this make compared to reading the temperature on the outside surface of the fermentor thats been insulated with foam?


Quite a few people have noticed a difference, some people have noticed no difference.
Personally speaking, I can't be arsed doing tests - logically it makes sense. It's right in the middle of the fermenter, immersed in wort and less exposed to the changing outside temperatures.

For the $20 or so it cost me, I'll err on the side of caution. I like to give my beer every chance possible to be awesome.


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## Spiesy (19/8/14)

Nick R said:


> This is what I do as well. Just put a stainless thermowell through the side wall of my bunnings fermenter. Takes about 5 minutes to do, and that includes the time getting the drill out of the shed.


I'm surprised more people don't do it. Cheap and quick enough to do.

It's odd, some people worry about the resolution of their STC/temp-controller, that it only displays 0.5 resolution - and then leave the probe taped to the outside of the fermenter, or worse, in a water filled beer bottle inside the fridge... :blink:


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## kiwisteveo (19/8/14)

cheers for all the replies/comments I brought a plastic bulkhead for the probe to go through wall of fermenter and the probe directly into wort cause it was cheaper than SS thermowell so will do that today with a single hop bravo brew but looks like best option will be SS thermowell for other fermenters in the future.


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## SJW (19/8/14)

Probe in with cling wrap over the top of fermenter.


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## superjim (19/8/14)

Pics as promised.


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## TheWiggman (19/8/14)

Spiesy said:


> It's right in the middle of the fermenter, immersed in wort and less exposed to the changing outside temperatures.


In my opinion you're best off having it offset a little from the centre of the fermenter (like post #14) to avoid overshoot with a temp controller like an STC-1000. Only really matters if you're doing temp changes (like stepping a lager), and even then only if you're using a lot of power to heat/cool.

Having it in the middle will allow a temp gradient through the wort from outside in. For example, once the temp might chill to your setpoint of 12°C the freezer/ambient may be -10°C and the outside boundary of the wort might be 9°C. The vessel will continue to get colder after the freezer turns off. Having the sensor closer to the edge will reduce this effect. The outside temps are being used to control the inside temps after all.

Bleeding edge, but it's zero extra hassle for that little bit of improvement in control.


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## Spiesy (19/8/14)

TheWiggman said:


> In my opinion you're best off having it offset a little from the centre of the fermenter (like post #14) to avoid overshoot with a temp controller like an STC-1000. Only really matters if you're doing temp changes (like stepping a lager), and even then only if you're using a lot of power to heat/cool.
> 
> Having it in the middle will allow a temp gradient through the wort from outside in. For example, once the temp might chill to your setpoint of 12°C the freezer/ambient may be -10°C and the outside boundary of the wort might be 9°C. The vessel will continue to get colder after the freezer turns off. Having the sensor closer to the edge will reduce this effect. The outside temps are being used to control the inside temps after all.
> 
> Bleeding edge, but it's zero extra hassle for that little bit of improvement in control.


Good idea.


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## Blind Dog (19/8/14)

TheWiggman said:


> In my opinion you're best off having it offset a little from the centre of the fermenter (like post #14) to avoid overshoot with a temp controller like an STC-1000. Only really matters if you're doing temp changes (like stepping a lager), and even then only if you're using a lot of power to heat/cool.
> 
> Having it in the middle will allow a temp gradient through the wort from outside in. For example, once the temp might chill to your setpoint of 12°C the freezer/ambient may be -10°C and the outside boundary of the wort might be 9°C. The vessel will continue to get colder after the freezer turns off. Having the sensor closer to the edge will reduce this effect. The outside temps are being used to control the inside temps after all.
> 
> Bleeding edge, but it's zero extra hassle for that little bit of improvement in control.


Good point

Intuitively it would seem that the air inside the fridge itself would stabilise relatively quickly when heated or colled compared to the fermenting beer so that even though I have a specific heating and cooling sources, their location is unlikely to play a significant effect on the temperature differentials inside the fermenting beer.

Interested if anyone thinks this is not right


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## TheWiggman (19/8/14)

Largely right I'd say Blind Dog. The liquid will contains a lot more thermal/heat capacity (often referenced here as 'thermal mass') than the air, so energy required to increase the temp of the air in the fridge is much, much less than required for the same temperature difference in the liquid.

If the fridge was cooling and is turned off, the wort will drop in temp and pass some of its heat to the air until they're the same temp
If a belt was heating and is turned off, it will pass its heat into the wort until they're the same temp

As for the speed... well they'll both stabilise at the same rate (because they will both eventually be the same temperature), but the temp difference that the air dropped will be a lot more than the wort dropped.

The location _will _play a part for the reasons above. The further something is away from the source, the more energy will be passed onto its surroundings first.
If you were in a large cold room would you rather stand on the opposite side and wait for the whole room to heat up or be right next to the heater? And if you stood on the other side of the room and you got warm, what would happen if you realised the heat was turned up too much? By the time you find out the room's already too hot, and you'd have to wait ages for it to cool down. (this is 'overshoot', which can be prevented or minimised using PID control).

The fementer is like the latter example. With the exception that the fermenting wort will generate heat, so to maintain the right temp the ambient air needs to be cooler than the desired fermenting temp.


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## Coalminer (19/8/14)

TheWiggman said:


> In my opinion you're best off having it offset a little from the centre of the fermenter (like post #14) to avoid overshoot with a temp controller like an STC-1000. Only really matters if you're doing temp changes (like stepping a lager), and even then only if you're using a lot of power to heat/cool.
> 
> Having it in the middle will allow a temp gradient through the wort from outside in. For example, once the temp might chill to your setpoint of 12°C the freezer/ambient may be -10°C and the outside boundary of the wort might be 9°C. The vessel will continue to get colder after the freezer turns off. Having the sensor closer to the edge will reduce this effect. The outside temps are being used to control the inside temps after all.
> 
> Bleeding edge, but it's zero extra hassle for that little bit of improvement in control.


Must agree with this as that is how mine is set up
It is half way between the edge and the center. I figure that will give me an average of the whole system
Bear in mind that there is a lot of movement and mixing of an actively fermenting wort and that should even out the wort temperature
Just my opinion. (for what its worth)


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## storeboughtcheeseburgers (19/8/14)

I just have it in a cupboard and let the probe sit flush against the inner door of the cupboard about half way down. I figure yeast generally brews at a higher temp once its going, so 18 degrees in a 1.5 X 1m I have had no dramas. 

Heat belt is indirect, but close.


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## Dips Me Lid (20/8/14)

I use the Keg King controllers for my plastic fermentors, the probe fits nice and tight into a SS keg dip tube which I use as a thermowell to get right down into the liquid, I flatten one end of the dip tube with a vice, drill a 20mm hole through the fermentor lid and use a 20mm cable gland to seal it up, I've set mine up just slightly off centre.


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## Topher (20/8/14)

Tried the thermowell ...... but it kept falling through the glad wrap. 

Seriously I do the same, tape and some foam. But I am gonna try the Occy strap method next brew, the bloody tape keeps coming off. Twice the temp probe has fallen right out of the fridge......Had one stout go to 28 degrees and ferment right out in a day, and my current brew had a tropical holiday at 30c but only only for a few hours.


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## mofox1 (20/8/14)

Topher said:


> Tried the thermowell ...... but it kept falling through the glad wrap.
> 
> Seriously I do the same, tape and some foam. But I am gonna try the Occy strap method next brew, the bloody tape keeps coming off. Twice the temp probe has fallen right out of the fridge......Had one stout go to 28 degrees and ferment right out in a day, and my current brew had a tropical holiday at 30c but only only for a few hours.


I left out the good bit... Big block o' blutack over the sensor, holding it in place, and beefing up the thermal mass around it. The polystyrene/murdered stubby holder goes over that, and held on by tape/ockies.

That way if the tape (or ocky straps) give way, it is still stuck to the side of the vessel, just not as insulated as it used to be.

Also makes it easy to switch it over to my stir plate, or whatever else I'm psuedo-temp controlling at the time. But then I'm sure someones got a thermowell in their stir plate too and will claim this as the superior method. h34r:


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## storeboughtcheeseburgers (20/8/14)

Depends how cold it gets where you are - I find I'm getting 11 minimums in a closed cupboard with no heating source, so don't really go to much effort (just hang a heat strap from a pipe in the cupboard) and put the probe in the inside, about 50% down and close the doors.

If your in Tassie or vic or whatever u prob could be a bit more pedantic but winter will be over soon anyway - then the madder brewers can start doing lagers, just to go against the seasons and have all different combos of measurements and engineering just cuz they can .


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## superstock (20/8/14)

Do you guys just slide your temp sensor into the thermowell dry?
Most thermowell controlled devices in industry have oil/liquid in the thermowell to transmit temp more directly, accurately and responsive to the sensor.


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## vykuza (20/8/14)

I do - I figure it's close enough and not enough air movement in and out of the thermowell's core is going to make a difference. You could also put a plug of play-doh in the end if you want to be super keen on it.


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## Mattress (20/8/14)

superstock said:


> Do you guys just slide your temp sensor into the thermowell dry?
> Most thermowell controlled devices in industry have oil/liquid in the thermowell to transmit temp more directly, accurately and responsive to the sensor.


Mate, C'mon.
We're only making beer.
It's not like we get all super anal about our processes.


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## superstock (20/8/14)

Mattress said:


> Mate, C'mon.
> We're only making beer.
> It's not like we get all super anal about our processes.


I totally agree with you. Against the FV wall, insulated & taped does me. However, from the posts, there are others out there with controllers setable to 1/10 degree, using thermowells in the best position for best reading and not using best practice to ensure accuracy. :huh:


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## mofox1 (20/8/14)

superstock said:


> Do you guys just slide your temp sensor into the thermowell dry?





Mattress said:


> It's not like we get all super anal about our processes.





superstock said:


> I totally agree with you. Against the FV wall, insulated & taped does me.


Based on the current trend this topic is taking... that's a little too much information. But hey, whatever rocks your fermenting fridge. B)


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## nathanvonbeerenstein (20/8/14)

Im doin it a littleeee different and using a stainless K-type thermocouple thats secured into my fermenter. Bit more contact and accuracy over a thermowell and less movement than just chucking it in the wort! Works for me


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## Hawko777 (1/9/14)

If you use yeast slants, you can clean one out drill small hole in top lid. Then fill slant with water and replace cap with your probe poking through it into the water and afix to side of fermenter with tape. This insures you dont get fridge turning on frequently and possibly damaging fridge and using more power than necessary ( that is if you connected a pid temp controller to turn fridge on and off). The minimum amount of water should be enough so as not to over or under shoot your temps. This is what I have done.

Good luck


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## schtev (3/9/14)

mofox1 said:


> Based on the current trend this topic is taking... that's a little too much information. But hey, whatever rocks your fermenting fridge. B)


Guys, are we still doing phrasing?


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## elcarter (3/9/14)

I must be the only one that just throws the probe under the glad wrap and seal and lets it float around in the middle of the fermenter.


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## Adr_0 (3/9/14)

nathanvonbeerenstein said:


> Im doin it a littleeee different and using a stainless K-type thermocouple thats secured into my fermenter. Bit more contact and accuracy over a thermowell and less movement than just chucking it in the wort! Works for me
> 
> 
> 
> ImageUploadedByAussie Home Brewer1408540195.364455.jpg


accuracy?


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## TheWiggman (4/9/14)

I concur, how sure are you that the K-type thermocouple is reading correctly at that range nathanvonetc.? They're known to be out by +/-2°C. I use them for my HERMS and have to check how much they are out every brew so I can accomodate for the error.




Hawko777 said:


> ... This insures you dont get fridge turning on frequently and possibly damaging fridge and using more power than necessary ( that is if you connected a pid temp controller to turn fridge on and off). ...


Take a lof of care using PID controller on a fridge. Unless it is purpose-made for fridge control, it's a fast way to kill a compressor. This includes the mounting arrangement you're suggesting. A thermostat or STC-1000 type controller is far more suitable.


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## Adr_0 (4/9/14)

Using a fridge with a time-proportional PID controller is pretty much the worst idea ever if you don't know what you're doing. These PID controllers turn the output onffor a percentage of a nominated time, eg 2 or 10 seconds for an immersion heater. This is obviously not that flash for a fridge to be turning on fur 0.4 seconds every 2 seconds. I guess you could make this 5min fur the freezer/fridge. If you had a variable frequency drive on the compressor and a 0-100% output, that would be cool. 

There are smarter on/off controllers that measure rate of change and then roll off the cycles. The most obvious example is BrewPi. I'm sure there are others out there.


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## nathanvonbeerenstein (8/9/14)

Adr_0 said:


> accuracy?





TheWiggman said:


> I concur, how sure are you that the K-type thermocouple is reading correctly at that range nathanvonetc.? They're known to be out by +/-2°C. I use them for my HERMS and have to check how much they are out every brew so I can accomodate for the error.


really accurate actually! i use an Atkin's Aquatuff which provides a plus or minus 0.3*c accuracy at ambient temperatures, the probe is a cheap one and the cable to the connectors a bit long so the reading is slightly delayed but this is no issue for the relatively slow moving temps of fermentation, tested it in ice water compared to the short high-quality probe that came with the unit and got the same reading to a degree with only 0.2 difference.


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## macca05 (8/9/14)

I used to tape mine to the side until I couldnt be bothered anymore. Now I just place it into the wort under gladwrap and I have found my temp is so much more stable than previously. Just a spray with sanitiser and a few wipes a couple of times and shes been good. Touch wood 
Macca


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## stm (9/9/14)

Option D seems to work for me.


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## TheWiggman (3/2/15)

Revelation: taping to the side of a fermeter doesn't do a great job for me. ACTUAL REAL-LIFE PIC OF FERMENTER SHOWN BELOW -




I scored this fridge last week which has an internal circulation fan - perfect (found on the side of the road, the owner said "it's no good, it freezes things all the time and we couldn't fix the temp adjuster thing". Whimmy-wham!).

I set my STC-1000 to 10°C for my pilsner. Yeast nutrient, 02 for 1 min. Noted activity after 12h.
Day 2 - not much action. Check SG which had dropped 3 points. Bumped temp to 11°C
Day 3 (yesterday) - _just _beginning to see krausen.
I've noticed that the 'new' fridge seems to run a lot for a fridge trying to achieve 11°C.
Considering it should be well underway by now I put a glass (which you can see in the pic) next to the fermenter with my thermometer in it. I left it for a few hours and came back to see it sitting at 6°C. As far as I'm concerned the two liquids should be the same because the air is being recirculated. This explains the slow start, and I gave the pilsner a gentle stroke to show my appreciation that even though it was at 6°C, it was still fermenting.

I had my STC-1000 adjust to +1 so in effect it was set to 10°C, but still controlling 4°C lower than set value. To account for this I've adjusted the offset but it goes to show that it's hard to trust the sensor if it's not submersed.

Yes, I have checked the accuracy of the STC temp probe with my thermometer before and yes, I will be buying a submersible probe tonight. Life's too short to gamble with pilsners.


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## stux (3/2/15)

superstock said:


> Do you guys just slide your temp sensor into the thermowell dry?
> Most thermowell controlled devices in industry have oil/liquid in the thermowell to transmit temp more directly, accurately and responsive to the sensor.


Great idea, but my impression with the temp mate probes I have is that they're more splash resistant than water proof. 

I use option e) lid with SS thermowell (from beer belly)

The thermowell is positioned halfway between the wall and centre. Figure this gives a more average reading. And about a third to half way up from the bottom. Depending on depth of fermenter. 

I slide the thermowell through the grommet lubrucated with starsan, but try to keep the thermowell dry (ish) on the inside. It invariably has some starsan in it. In the past I was not so careful and my probes (they're not rubber like Stc probes) show signs of verdigris/corrosion. 

I use a heatbelt placed wrapped around above the tap, and have found this corrects for heating overshoot compared to just using a heater in the fridge cavity. Could perhaps be solved with a PID, but I already have temp mates/stcs


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## Spiesy (3/2/15)

TheWiggman said:


> Revelation: taping to the side of a fermeter doesn't do a great job for me. ACTUAL REAL-LIFE PIC OF FERMENTER SHOWN BELOW -
> 
> 
> 
> ...


Why don't you draw out some wort/beer to test?

There's always a chance that your wort is fermenting and creating heat, but your new fridge is struggling to chill it enough (you did mention its on a lot). 

Mind you, I've noticed a 1-degree difference in probe outside or inside, but mine is on a stainless fermenter, which is a better conductor of temperature.


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## TheWiggman (3/2/15)

Fair call, and the answer is tightarseness. Considering I just coughed up $40 in thin metal tubes I'll draw off a 30 cent sample and measure that.


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## pcmfisher (4/2/15)

TheWiggman said:


> Revelation: taping to the side of a fermeter doesn't do a great job for me. ACTUAL REAL-LIFE PIC OF FERMENTER SHOWN BELOW -
> 
> 
> 
> ...


If you are confident about the accuracy of your stc, the temp it is reading insulated to the side of your fermenter is the one you should be taking notice of. It may even read a couple of degrees cooler than what your fermenting beer actually is. 

The glass of water doesn't mean much.


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## TheWiggman (4/2/15)

not confident of the reading of the STC.



pcmfisher said:


> The glass of water doesn't mean much.


Why not?


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## manticle (4/2/15)

Fermentation generates heat. The glass of water won't. Fermenter also has more thermal mass than a small glass of water and is insulated by a different material. About the only thing the two have in common is that they are both volumes of liquid inside a container.


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## paulyman (4/2/15)

I've seen a few mentions in the discussion about people putting the probe in the wort under the cling wrap. Anyone had any issues with this?

I am probably going to buy a few SS thermowells, but that won't be until I get around to buying a step drill bit and ball valves to install in my brew rig for a less ghetto recirc. So this would be a good stop gap while I wait if people have had success.


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## seamad (4/2/15)

paulyman said:


> I've seen a few mentions in the discussion about people putting the probe in the wort under the cling wrap. Anyone had any issues with this?
> 
> I am probably going to buy a few SS thermowells, but that won't be until I get around to buying a step drill bit and ball valves to install in my brew rig for a less ghetto recirc. So this would be a good stop gap while I wait if people have had success.


Have been putting the probe straight in without issue for years Give it a wash with warm napisan then a quick soak in some starsan and under the glad wrap it goes. After all you want to measure wort temp.


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## paulyman (4/2/15)

Cheers Seamad, years of positive data sounds good to me. Will give it a go in the next brew.


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## TheWiggman (4/2/15)

manticle said:


> Fermentation generates heat. The glass of water won't. Fermenter also has more thermal mass than a small glass of water and is insulated by a different material. About the only thing the two have in common is that they are both volumes of liquid inside a container.


Respectfully manticle, that's the misunderstanding and the reason I asked (a little facetiously). All the above matters naught bar the fermenter generating heat if the temp of the environment is constant. 
If (if) the temp of the fridge is 4°C, so will be everything in the fridge given time. The volumetric heat capacity (what's meant by thermal mass, which is a term used in building) will determine the rate at which the vessel gains or loses heat from/to the environment. Will happen much faster to the small vessel.
The material it's made of, much the same. 
In a fridge, over time, a large and small vessel (not fermenting beer) will be roughly the same temp if using the small vessel's temp to control. It will cycle more often but be more tightly controlled. 
If using the large vessel, the small vessel will get colder but will eventually increase to the temp of the large vessel. 
Now in my case (when I posted the pic) I adjusted some settings on the STC to extend intervals and waited until it was to cut back in before checking. Then checked later again to confirm. I double-checked last night as per Spiesey's recommendation and found the wort to be a degree and a half warmer than the glass of water, and it was actively fermenting. Adjusted the STC offset to suit (disregarded glass of water), and I think it's pretty bloody accurate now until I get my dip tubes. 
My post was admittedly alarmist but I'm pretty confident if you use the ol' bottle of water with probe in the fridge technique, and you know the difference between it and a fermenting beer generating heat, you're going to be accurate within a degree.


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## michaeld16 (4/2/15)

But isnt it just as easy to stick it on the side of the fermenter and not have to worry about working out the difference between fridge air temp and fermenting wort


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## TheWiggman (4/2/15)

I just deleted my reply over-analysing things. I think I should talk less publicly and take my own advice sometimes.

Yes you are right. The biggest mistake I made was not calibrating the STC-1000 to the temp in the wort, regardless of lengthy investigation or explanations. Submersing in the liquid (beer/wort) is the only true way to know the temp though.


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## manticle (4/2/15)

TheWiggman said:


> Respectfully manticle, that's the misunderstanding and the reason I asked (a little facetiously). All the above matters naught bar the fermenter generating heat if the temp of the environment is constant.
> If (if) the temp of the fridge is 4°C, so will be everything in the fridge given time. The volumetric heat capacity (what's meant by thermal mass, which is a term used in building) will determine the rate at which the vessel gains or loses heat from/to the environment. Will happen much faster to the small vessel.
> The material it's made of, much the same.
> In a fridge, over time, a large and small vessel (not fermenting beer) will be roughly the same temp if using the small vessel's temp to control. It will cycle more often but be more tightly controlled.
> ...


Over time, everything will equilibrate sure but it is the early part of fermentation where temp is key. How much time for 20 L of heat generating liquid to match 100 mL of non- heat generating liquid?


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## Matplat (5/2/15)

I filled my fermenter with tap water which came out around 28deg, then set the temp on the STC to 18 and stuck the probe on the outside using blu-tack (acts both as an insulator to air temp, and a heat transfer medium from the FV). I figure this is a reasonable approximation of cooling a wort as I am cooling something that is hotter than desired temp.

When the STC got to 18deg the water temp was 2deg higher, this data point is only relevant when the temp probe first reaches it, as obviously the system would equalise over time as no heat is actually being generated by the water.... I will be setting my STC 2deg below desired temp with the probe on the outside where it doesn't need sanitising and doesn't get sticky. :beer:


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## mosto (5/2/15)

I just dangle the probe so that it's up against the side of the fermenter(s). I've done a couple of basic tests and concluded that the wort will be roughly 2c higher than the air temp, so I set my STC accordingly. I often have two fermenters (20L jerry's) in the same fridge, in which case the probe is wedged between two, essentially insulated by the two batches of wort.


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## gezzanet (5/2/15)

I use plastic fermenters. I Use the lid instead of glad wrap because I have a ss thermowell in the lid held in place by a airlock grommet. Probe sits in the thermowell. Works great. No liquid or grease in thermowell. I tried the thermowell with and without grease and no real difference. Grease just makes it messy when you skip it in or out. Lol


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## mofox1 (5/2/15)

Does said thermowell go down under liquid level? Where do you get such beasts?


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## stux (5/2/15)

mofox1 said:


> Does said thermowell go down under liquid level? Where do you get such beasts?


Yes.

Here: http://shop.beerbelly.com.au/fermentor-thermowell-9-53mm-x-400mm-stainless-steel-with-grommet.html


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## TheWiggman (5/2/15)

I got me two of them too mofox. Other option (for me) was this from craftbrewer: http://www.craftbrewer.com.au/shop/details.asp?PID=955
It was twice the price and only 200mm long, so probably not long enough through the lid if I wanted to do a 10l batch in my Coopers fermenter.

Just quietly beerbelly shipped them the afternoon I ordered them. Very happy with that.


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## tugger (5/2/15)

Or in the bung hole.


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## mofox1 (5/2/15)

tugger said:


> Or in the bung hole.
> 
> 
> 
> ImageUploadedByAussie Home Brewer1423109239.925153.jpg


lolz


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## mosto (5/2/15)

tugger said:


> Or in the bung hole.
> 
> 
> 
> ImageUploadedByAussie Home Brewer1423109239.925153.jpg


What are you measuring the temperature of??? :unsure:


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## TheWiggman (5/2/15)

Just installed my beer belly dip tube, ruining a lid in the process. 
Took it off the side of the fermenter, then stuck it in the dip tube. Dip tube was 0.3°C cooler. This is with an air circulated fridge.


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## daveHQ (5/2/15)

TheWiggman said:


> Just installed my beer belly dip tube, ruining a lid in the process.
> Took it off the side of the fermenter, then stuck it in the dip tube. Dip tube was 0.3°C cooler. This is with an air circulated fridge.


As Dr Karl would say "do the experiment"!!!!


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## droid (5/2/15)

feck it, just ordered the ss thermowell


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## Exile (5/2/15)

Got mine from brewershardware.com the 12" one
I found the one with the grommet in the pic above kind of loose, and it was a bastard to remove and clean.


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## Spiesy (6/2/15)

Can't believe this thread is still going... or can I?


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## Coalminer (6/2/15)

TheWiggman said:


> Other option (for me) was this from craftbrewer: http://www.craftbrewer.com.au/shop/details.asp?PID=955


These are brilliant. It fits a standard airlock grommet perfectly
Mine is set up halfway between edge of fermentor and the centre but does not seem to matter (found by experiment) as convection currents in the fermenting wort even out
the temps across the whole fermentor.
I use male/female RCA plugs from Jaycar to connect to STC1000 so easy to disconnect when removing fermentor from fridge


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## azampech (6/2/15)

I lower mine through the airlock gromet and hold at correct 'depth' with a peg.


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