Where Abouts Did I Shove My Probe?

[rendo]

Hi All,

Cheers to Pok for the subject title. I've done lots of reading on this topic and thought I would share what I did and why.

I finally have a brew fridge and couldnt decide where to put my temp probe for the digital thermostat.

1. In the brew
2. Outside the brew on the fermenter/above the brew line/below the brew line, covered with some insulation, not covered
3. In a jug of water in the fridge
4. Just hanging in the fridge, suspended in air as such
5. Some place pretty nasty that would produce really sh!tty beer if it ever dropped into the brew.


​

I ruled out #5 very quickly. There are so many good posts here that all have very valid reasons for doing it either way. Here is what I think.

I have the probe on the outside of the fermenter, with a stubbie holder cut flat over it (neoprene?), with a bit of velcro that wraps around my fermenter that holds it all in place. Very importantly I also have added a fan (ex-computer power supply fan) in to the fridge, I had two, but that was giving way too serious air flow. One is plenty!

My problem with putting the probe against the fermenter is that it can make the fridge over cool the brew. Once the brew reaches say 18degrees if that is your setting, the fridge stops,but since the fridge is so cold, it will still continue to chill the brew somewhat...called overshoot. Its like trying to stop dead RIGHT at the finish of a 100m race, yeah right. Yet most people only had +/- 1deg, my ebay dig thermo has +/- 0.3degrees! Fantastic.
The fan is explicitly to get around the overshoot, my thoughts were that it will force the fermenter and fridge temps to converge as it is cycling the air around the ferm so much.

So far, i am thinking this is exactly what happened. When the brew first got to 18deg, the fridge was 13 deg. After 1/2 day, when the brew was 18deg, the fridge was 17deg. Looks like its possibly working for me. The fridge turns on every so often,once an hour maybe. Temps of fridge and brew still within 1 deg. Without the fan, this convergance just doesnt seem to happen. I am a firm believer that the fan makes a massive difference. It is on all the time regardless of the digital thermo stat.

The problem I have with leaving the probe in the air is that it would take tooooo long to cool the fermenter as the fridge will hit 18deg, well before the brew does. Many are right though in saying that this will give a most consitent brew result, but the lag time is too long in my opinion. You need to get that temp down in the initial stages of the brew....anyhow...

Jug of water/stubbie of water....pfft...not interested
In the brew....hmmm, too much hassle, cleaning, etc.

So there u have it, I just had to tell you all, as it was many nights reading this forum that helped me make the deicision.

Thanks all

 

[seravitae]

nothing useful to add as it's late at night and i misread the subject line as "where abouts do I shave my pubes?"

:unsure:

 

[rendo]

HAHAHA

i really shoudlnt comment, I did have something typed, but its just wrong...

nothing useful to add as it's late at night and i misread the subject line as "where abouts do I shave my pubes?"

:unsure:

 

[Nevalicious]

Hi All,

Cheers to Pok for the subject title. I've done lots of reading on this topic and thought I would share what I did and why.

I finally have a brew fridge and couldnt decide where to put my temp probe for the digital thermostat.

1. In the brew
2. Outside the brew on the fermenter/above the brew line/below the brew line, covered with some insulation, not covered
3. In a jug of water in the fridge
4. Just hanging in the fridge, suspended in air as such
5. Some place pretty nasty that would produce really sh!tty beer if it ever dropped into the brew.


​

I ruled out #5 very quickly. There are so many good posts here that all have very valid reasons for doing it either way. Here is what I think.

I have the probe on the outside of the fermenter, with a stubbie holder cut flat over it (neoprene?), with a bit of velcro that wraps around my fermenter that holds it all in place. Very importantly I also have added a fan (ex-computer power supply fan) in to the fridge, I had two, but that was giving way too serious air flow. One is plenty!

My problem with putting the probe against the fermenter is that it can make the fridge over cool the brew. Once the brew reaches say 18degrees if that is your setting, the fridge stops,but since the fridge is so cold, it will still continue to chill the brew somewhat...called overshoot. Its like trying to stop dead RIGHT at the finish of a 100m race, yeah right. Yet most people only had +/- 1deg, my ebay dig thermo has +/- 0.3degrees! Fantastic.
The fan is explicitly to get around the overshoot, my thoughts were that it will force the fermenter and fridge temps to converge as it is cycling the air around the ferm so much.

So far, i am thinking this is exactly what happened. When the brew first got to 18deg, the fridge was 13 deg. After 1/2 day, when the brew was 18deg, the fridge was 17deg. Looks like its possibly working for me. The fridge turns on every so often,once an hour maybe. Temps of fridge and brew still within 1 deg. Without the fan, this convergance just doesnt seem to happen. I am a firm believer that the fan makes a massive difference. It is on all the time regardless of the digital thermo stat.

The problem I have with leaving the probe in the air is that it would take tooooo long to cool the fermenter as the fridge will hit 18deg, well before the brew does. Many are right though in saying that this will give a most consitent brew result, but the lag time is too long in my opinion. You need to get that temp down in the initial stages of the brew....anyhow...

Jug of water/stubbie of water....pfft...not interested
In the brew....hmmm, too much hassle, cleaning, etc.

So there u have it, I just had to tell you all, as it was many nights reading this forum that helped me make the deicision.

Thanks all

Rendo, its funny, I have just finished my fermenting fridge setup (got the fridge off the net for $20 (its a 1960 Electrolux donk))...

Anywho, I spent ages like yourself, reading into where to put the temperature probe to obtain the best results. I did a trial run using a fermenter full of water, knowing full well that this will not give a 100% accurate result as fermentation generates heat etc, but I found that the most accurate way is to place the probe on the side of the fermenter below the fluid line. I covered the probe in a big hunk of Blu-Tak and then folded up a rag several times, placed that over the probe/blu-tak then using an old occy strap, held it all in place... Seems to work.

I am sans a circulation fan, but am open to the idea if you reckon that it may give a better result. I also thought about the hanging it in the air method but ruled this out as I didn't wan to over-cycle the compressor and stuff up a perfectly good fridge. I realise that the fridge cost $20 but the inconvenience of getting rid of a knackered fridge is of more concern that $20!!

Oh, I also have a glass of water in there with a glass thermometer in the liquid. Its currently at 12*, the fermenters digital thermomter on the side says 12*, and the fridgemate shows 12*, so I'm chuffed with the result. Has been running since friday morning (lager put down) and used 2kWH's of electricity, total on time of about 18 hrs (i have one of those digital cost meter thingos to measure just for shits and giggles) So far about 38 cents! Nice!

Anywho, just my opinion

Tyler

 

[rendo]

Good to hear from you, makes me think I am not going crazy.

Yep,i did so much reading and testing like you did too. Regarding a fan, just try it and see for urself. Thats what I did. I THINK its better, am certain it is, makes logical sense, BUT maybe u wont notice the diff....

one of those digital meters that measures the elec used/cost sounds GREAT....where do i get one of thiose? roughly how much?

CHEERS!!

Rendo, its funny, I have just finished my fermenting fridge setup (got the fridge off the net for $20 (its a 1960 Electrolux donk))...

Anywho, I spent ages like yourself, reading into where to put the temperature probe to obtain the best results. I did a trial run using a fermenter full of water, knowing full well that this will not give a 100% accurate result as fermentation generates heat etc, but I found that the most accurate way is to place the probe on the side of the fermenter below the fluid line. I covered the probe in a big hunk of Blu-Tak and then folded up a rag several times, placed that over the probe/blu-tak then using an old occy strap, held it all in place... Seems to work.

I am sans a circulation fan, but am open to the idea if you reckon that it may give a better result. I also thought about the hanging it in the air method but ruled this out as I didn't wan to over-cycle the compressor and stuff up a perfectly good fridge. I realise that the fridge cost $20 but the inconvenience of getting rid of a knackered fridge is of more concern that $20!!

Oh, I also have a glass of water in there with a glass thermometer in the liquid. Its currently at 12*, the fermenters digital thermomter on the side says 12*, and the fridgemate shows 12*, so I'm chuffed with the result. Has been running since friday morning (lager put down) and used 2kWH's of electricity, total on time of about 18 hrs (i have one of those digital cost meter thingos to measure just for shits and giggles) So far about 38 cents! Nice!

Anywho, just my opinion

Tyler

 

[Nevalicious]

I got my electricity meter thingamajig from Jaycar. Bout $29. I bought it to monitor power on a newly aquired beer fridge (is an older one also but was curious more than anything), used it for three months to figure out an average cost to run my beer fridge for a year.

When I set up my fermentation fridge I thought it would be interesting to see how much it costs to run. When I got the fridge I ripped it apart (took the door skins off and insulation, have since stuck large pieces of styrofoam to door) and the door seals needed replacing... Because it is essentially a shitty looking fridge, I didn't want to spend $80 odd on new seals. I went to Clark Rubber and got foam tape to seal the gaps. Gold, and cost bout $15 total.

So rambling a bit but yeah, they are handy to have. I guess you could also have a power board plug into it and monitor the consumption of a bunch of things at once...

Good luck

Tyler

 

[stm]

I think that this post:

http://www.aussiehomebrewer.com/forum//ind...st&p=411990

gives a really interesting analysis of where to shove your probe and discusses a few options. The poster's conclusion was to blu-tac the probe to the outside of a glass of water sitting next to the fermenter. With the next best solution appearing to be to just leave it hanging in the air, but beware short-cyling the fridge.

 

[rendo]

Hi stm,

The only thing that I cant get over with hanging it in the air (in the fridge), is that I feel it takes far too long to do the initial cooling of the brew down to the desired temp.

I have been thinking what I MIGHT try and experiment with is, having the temp probe against the side of the ferm, for the first day, until the brew is the right temp and there is some sort of equilibrium going on with the fridge/ferm. Then hang it in the fridge air....

Any thoughts on this? Anyone do this? I think I remember one guy doing this throught the reading I have been doing

Rendo

EDIT: and I am still convinced that a fan in the fridge really helps establish some kinda equilibrium/harmony between the ferm and fridge temp, by keeping that air in the fridge constantly circulating around the fridge/ferm

I think that this post:

http://www.aussiehomebrewer.com/forum//ind...st&p=411990

gives a really interesting analysis of where to shove your probe and discusses a few options. The poster's conclusion was to blu-tac the probe to the outside of a glass of water sitting next to the fermenter. With the next best solution appearing to be to just leave it hanging in the air, but beware short-cyling the fridge.

 

[stm]

"The only thing that I cant get over with hanging it in the air (in the fridge), is that I feel it takes far too long to do the initial cooling of the brew down to the desired temp."

Yeah, that's a good point. I hang it in the air (because I'm too lazy to set up a glass of water and blu-tac), but initially (for ales) set the fridge to 10degC for about 6 hours to pull down the wort temp a bit quicker and then re-set to desired temp. For me, this is 15degC fridge air-space. Seems to give me a steady 18degC at high krausen according to the sticker thermo, and is less frigging around. And my fridge hasn't blown up yet.

 

[glaab]

The problem I have with leaving the probe in the air is that it would take tooooo long to cool the fermenter

The only thing that I cant get over with hanging it in the air (in the fridge), is that I feel it takes far too long to do the initial cooling of the brew down to the desired temp.

What temp you pitching at? The pitching temp and the ferment temp shouldn't be that different.

 

[rendo]

Hi Glaab,

Agreed, would be good to have them the same or similar. I pitched at 25 and brewed at 18 deg.

What I want to do next time is put 20L in a cube in the brew fridge, get it down to 18 deg, then use that to brew. THat way I can easily control my pitching temps....good idea?

What temp you pitching at? The pitching temp and the ferment temp shouldn't be that different.

 

[glaab]

you could but it sounds like a lot of work for a lazy ******* like me, 2 kg of ice and you'll be at 20C easy enough, unless it's an AG and you don't wanna add water.

 

[rendo]

I almost made some ice for the last brew.....u dont buy it from the servo do u??

maybe next time will make some ice.

you could but it sounds like a lot of work for a lazy ******* like me, 2 kg of ice and you'll be at 20C easy enough, unless it's an AG and you don't wanna add water.

 

[glaab]

I have a few ice cream containers and make my own but have used plenty of bags from the servo and never had any problems with it, but it's a waste of money really. For a 45L batch of extract I might need 8-10kg.