A Great Place To Shove Your Temperature Probe

[lonte]

Can anyone see an issue with using aluminium tubing for a thermowell? A metre length from Bunnings costs a few dollars.

Alternatively, I guess a length of vinyl tube?

the vinyl may insulate a little? The aluminium will work as good if not better than SS for temp conductivity. but it raises the age old debate of Al in beer production and alzheimers and we don't want to go there...

 

[newguy]

the vinyl may insulate a little? The aluminium will work as good if not better than SS for temp conductivity. but it raises the age old debate of Al in beer production and alzheimers and we don't want to go there...

There is really no debate.

First, when aluminum is exposed to oxygen, such as that found in ordinary air, it forms a surface oxide layer - Al2O3. This compound forms almost instantaneously, and it is chemically almost identical to ruby. Basically, unless you use an angle grinder to shower your wort with aluminum particles, no aluminum will make its way into your beer.

Second, the original study that suggested a link between aluminum and alzheimer's disease was disproven a long time ago. The study used a dye which contained aluminum to stain the slides they examined.

The only real reasons that 'big' brewers don't use aluminum equipment are because it's a soft metal and caustic cleaners will react with it. Go into any restaurant and chances are all the big stock/soup pots will be aluminum. Aluminum is safe - don't worry about it.

 

[TidalPete]

having the probe hard up against the outside of the fermenter with a rag to insulate it from the cold fridge air is accurate to within 1/2 a degree of the actual wort temperature for me.

I'm quite happy to let my ferment temp range from 17-19 degrees on a constant up and down cycle. Does anyone really think they could tell the difference between a beer fermented like this and a beer fermented at a constant 18 degrees?

Spot on Coodgee. :beerbang:

:beer:

 

[marky_mark]

I've experimented with thermowells and having my fridgemate probe strapped to the side of the fermenter, comletely insulated from the fridge air by a piece of industrial grade insulation taped over it. The problem I faced was that the wort temp would swing by a few degrees before the compressor would kick in, meaning that there would be a lot of condensation building up on the outside of the fermenter as the fridge air temp hit 15-20 C and the beer was at 10 C. For lagers I don't really want hugh temp swings at all.

My solution was to scrap the whole insulation thing and simply use a piece of electical tape to strap the probe to the side of the fermenter. That way, the probe measures the wort temp, but is also influenced by the fridge air temp and hence will maintain very constant fermentation temperatures, down to less than a degree swing! Kind of counter intuitive to what has been discussed here but I think a valid point and somethig that took me a while to figure out. So try it guys. Just spreading the wealth of knowledge.

Cheers,

Mark

 

[bindi]

Bindi do you use a thermowell with that? If not how do you stop the wort soaking the cable?

Warren -

Waterproof cable and probe [covered in a small plastic tube just incase] <_< the chest freezer is not working as hard after the fermentation temp is reached and stable.

 

[The King of Spain]

I just stick it to the side of the fermenter with some electrical tape - works fine.

 

[oneills]

I'm with Mark and Deaves

I just tape the probe to the side of the fermenter with a piece of packing tape and it holds temp to within a degree using an Aldoheat temperture controller.

 

[bindi]

I'm with Mark and Deaves

I just tape the probe to the side of the fermenter with a piece of packing tape and it holds temp to within a degree using an Aldoheat temperture controller.

I did that for a few years but a probe in the wort is so much better, I also gave away my Aldoheats [2] to new brewers [one for a fridge, the other I can't remember :unsure: ] and went digital.

 

[Brad_G]

Hey guys,

What a good thread. Something I have thought for ages, but didnt know whether or not to discuss it as I thought it was common knowledge.

For interests sake, I was using a dip tube for a bit, but I didnt like the idea of something poking into my wort, so now I use electrical tape and i have not noticed a difference in my brews. I do drop the temp on my controller 1 degree though, compensation for the plastic.

Brad

 

[SpillsMostOfIt]

I've been vassilating between what I see are three methods - the aforementioned thermowell, taping it to the side or what I think I will probably do - making a neoprene mat which sits on the floor of my cooler and has a hole in it where the thermistor/sensor lives. The fermenter will sit on the neoprene (so it is nice and comfy) and the neoprene will effectively ensure that the temperature is very close to that of the bottom of the fermenter.

We all know/say that good temperature control is important (so there shouldn't be too much variation during fermentation), but I am guessing that the difference between temperature ranges of 16.8-18.5 and 17.0-18.0 (made-up values) is probably not going to be more/less noticeable in the end product.

Having said that, I believe that the errors in the system would be additive and most of the temperature controllers under consideration hold the temperature within a one degree range, so I can understand the desire to reduce error elsewhere.

I guess the thermal mass of multiple tens of kilograms of water makes an effective buffer, but we also are looking for two different cooling scenarios - 'Cool it down NOW!' and 'Keep it at a constant temperature'. I can't see how a simple refrigerator/freezer/cooler - using air to transfer heat - can be perfect.

But, I do have an answer for those with access to large-scale computer data centres...

 

[Batz]

I just stick it to the side of the fermenter with some electrical tape - works fine.

Same here,I use a few bits of that silver duc tape,the wide one.
Works as well as something stuck in the wort IMO,without having to have something stuck in the wort


Batz

 

[Korev]

I have found Blutack works well to hold the sensor on the outside of the fermentor

Peter

 

[PistolPatch]

Great to see this got off-topic so quickly It was meant to be about crash-chilling but now it seems to be about where to shove your probe after pitching. This getting off-topic has worked out well for me because you guys have got me thinking especially MarkyMarks post.

Lets see if I can summarise what this and subsequent posts got me thinking about

If you put your probe in the wort, like I have done, and you use a Mashmaster probe, your wort temp will cycle between, in our example of 18 degrees, 16 and 20 degrees exactly.

What MarkyMark and others are saying is that shoving your probe where I did (the airspace above the wort in the fermenter) or on the outside of the fermenter will give you lesser range, maybe even half a degree either side.

This sounds great to me and a lot easier than mucking around with the dip tubes like Ive been doing.

Have I got that summary right?

Thanks,
Pat

P.S. Please excuse my not responding to the earlier posts.

 

[Ross]

What MarkyMark and others are saying is that shoving your probe where I did (the airspace above the wort in the fermenter) or on the outside of the fermenter will give you lesser range, maybe even half a degree either side.

How on earth can monitoring the airspace, give you better temp control than measuring the wort :huh:
I'm keen to be educated B)
My worts stay within half a degree of my set point.

cheers Ross

 

[BrissyBrew]

Hi PistolPatch I am also selling the stainless steel probes as separate items as well.

 

[Wortgames]

Ross, I guess it's a case of how wide of the mark your trigger points are.

If you have a controller which allows the subject to vary say 2 degrees before it activates, then having the probe in the wort would mean that the wort has varied 2 degrees before the controller responds.

If the sensor is in the airspace, then the controller will trigger more frequently as the airspace varies that 2 degrees, but the wort would presumably maintain itself at an average temperature somewhere in the middle of the range.

I guess it isn't such a big deal with narrow deadband controllers, but it might be a better way to regulate temps if you have a less precise controller.

Another issue might be that by the time the wort has registered a temp increase, the fridge has already warmed up and it will take a few minutes of chilling to chill the fridge and then the wort - by which time the wort may have warmed even more. Similarly, by the time the wort has cooled enough to turn off the controller, the fridge is probably pretty frosty, and the wort may continue chilling for a while after the controller turns off. Kind of a thermal flywheel effect.

I think it's splitting hairs really, I doubt that fluctuations in the order of a degree or two would make much difference to a brew!

 

[PistolPatch]

How on earth can monitoring the airspace, give you better temp control than measuring the wort :huh:
I'm keen to be educated B)
My worts stay within half a degree of my set point.
cheers Ross

Rossco, this is the advantage of being unemployed in WA. I have the time to think through the above posts. It took me 3 days to understand the above :blink: I have no idea what to add to what Wortgames said apart from the trigger word, 'buffer.'

The air cushion acts as a buffer and this means it will cool before the wort does. This means that the wort doesn't have to cool a whole 2 degrees before the controller kicks in. Vice versa on the upside.

Bloody good idea I reckon. Takes some undistracted thought though to see the sense in it and I've got plenty!

Spot ya,
Pat

P.S. Brissy. Stainless steel probes - you champion, we need some pics!!! Throw a link in here. I have some other ideas on probes as well! Give me a few days.

 

[Ross]

I'm not a fridgie, but my understanding was it's not a good idea to have your compressor switching on & off continually, hence the large temperature dead band in a normal fridge/freezer. If you measure the airtemp with such a tight setting, surely your fridge will be switching on/off all the time.
Measuring airspace, will not keep an active ferment at your desired temperature, submerging your probe or fixing to outside of fermenter will work much better.

Wortgames - i agree, if you have a large deadband, then measuring air temp would be better but that's not the case with the unit we are talking about...

cheers Ross

 

[bindi]

How on earth can monitoring the airspace, give you better temp control than measuring the wort :huh:
I'm keen to be educated B)
My worts stay within half a degree of my set point.

cheers Ross

I'm not a fridgie, but my understanding was it's not a good idea to have your compressor switching on & off continually, hence the large temperature dead band in a normal fridge/freezer. If you measure the airtemp with such a tight setting, surely your fridge will be switching on/off all the time.
Measuring airspace, will not keep an active ferment at your desired temperature, submerging your probe or fixing to outside of fermenter will work much better.

Wortgames - i agree, if you have a large deadband, then measuring air temp would be better but that's not the case with the unit we are talking about...

cheers Ross

I agree with the above stick it in the wort, I am a new convert to this [last few brews] and have noted that the chest freezer [ferm fridge] and controler are not working as hard IMO.

 

[BrissyBrew]

Ross has a point about switching the compressor on and off, more switching more wear, the shorter the lifespan. That aside there are a couple of points to make.

I think the best solution varies accordingly to when we are in the fermentation cycle.

Early in the cycle I am for having a probe inside the wort, as fermentation it self generates heat. The only caveat I have with this is what that you don’t overshoot your fermentation temperature if you are crash chilling in the fridge. The easy way to get around this is to pop back and give your fermenter a rock back and forwards for the first few hours until you are close to your set fermentation temp. With your probe in the wort you will get to your fermentation temperature quicker, you just need to wait that the wort does not drop below your fermentation temp due to the buffer the wort provides. If drilling a hole in a plastic fermenter maybe offset the hole to the side may assist. You can leave your probe immersed inside the wort for the rest of the fermentation period, I do and I don’t think the two degree dead band makes a huge difference. Otherwise you could just pull the probe up a little bit so that it sits in the head space and yes the wort will be a more stable temp (excluding heat generated from the fermentation process.

Now lets say you wanting to use a controller to convert a chest freezer for wine storage (I know a few people who have done this, some of them work for the biggest wine produces in Australia). You want to keep the wine at nice stable temp and avoid any temp fluctuations. Don’t forget to cling wrap necks of the bottles, helps control humidity and keep the labels looking good. If the probe is placed in the air, even with a two degree dead band after some time the liquid in all the bottles will stabilise, you can assist this process by placing a small fan inside the freezer to make sure you have a nice even circulation of temperatures, that way you don’t get a difference between the to and the bottom of your fridge. I had been advised that the recorded variations on the temperature of the liquid in the bottles over a period of time using a data logger was less that 0.5*C (closer to 0.3*C if memory serves me right).