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Chezza

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Good morning Mr Chrome A. Key,

 

I'll start by covering my rather large backside with "it depends". Having said that:

 

Firstly, as I'm sure you know, make a simple insulating cover for the probe so it is only recording the temp from the outside fermenter wall and not the ambient air temp in the fridge. Some use a cut out piece of foam, some use a cut up rubber-type stubby holder etc. Using tape of some sort, affix it to the FV.

 

If you have a fan to actively circulate the air, then it doesn't matter so much as long as it's at a level where there is wort in the FV.

 

If no fan, and there's only one fermenter in the fridge, or there's a few and both are the same height above the base of the fridge, about halfway up the fluid level of the FVs is good. If there are some at two levels (see Ben's pic in Post #42), I'd suggest toward the base of the higher fermenter.

 

Hope that makes sense, and cheers

Phil

 

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Thanks Antiphile.

 

I suppose what i was thinking though is in the case of 2 fermenters (1 above the other in the fridge)

 

Normally i have my temp probe attached to the 1 fermenter and insulated with bubble wrap. I just wait until that ferment is pretty much done and then move to a new brew.

 

I haven't been able to find a way to have 2 brews at different levels in the fridge at the same time other than just controlling the ambient temp of the fridge (i have a fan in the fridge to help keep the temp pretty stable at all levels)

 

I realise the fridge ambient temp will be quite different to the fermenters internal temp when the fermentation is really kicking along. So how do people deal with this when they have 2 fermenters 1 above the other?

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Hi again, Big Boy

 

I didn't explain myself very well, did I? That bubble wrap is one of the good tricks I'd forgotten about. Yet, since you have a fan in the fridge, all is well and you won't have any probs.

 

It was explained to me by my brew guru a while ago. Without a fan to circulate the fridge air, it will "layer" bands of air, colder at the bottom and warmer at the top; very much like scuba divers experience the deeper they go. Of course, it depends on the vertical height of the interior of the fridge, but he said he placed two thermometers in a 2 metre high fridge, top and bottom, and said it was not uncommon to have a 4 or even 5 degree C difference between them.

 

But with have a steady air circulation from the fan, you won't experience any significant difference at all, so it really shouldn't matter where the temp probe is placed.

 

Cheers mate.

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So with that notion' date=' just leave the probe somewhere central and set the brew fridge to say 17c and hope for the best?[/quote']

 

That would be my plan. Cover the temp probe with bubblewrap and tape to a fermenter. The fan and temp controller will keep the air temp at a steady temp once the probe detects the wort temp is 17C. If you then put in a second FV, it will take a few or more hours to cool down to 17C, and may be half a degree or so above 17C whilst actively fermenting due to the heat being put out by the chemical processes, but it will be so close as to not make any significant difference in any way.

 

Cheers

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  • 1 month later...

After my last batch fermented out around the 28-30° C mark, I decided to take a break from brewing until I could sort out some kind of temperature control. We were given a small bar-fridge years ago that we never used for anything (and were thinking of selling at one point), but after a rather excited (and successful!) test-fit of the Craft fermenter, it was destined to start a new life as a fermentation chamber. At first, I was tempted to grab an STC and be done with it, but decided to go about building my own, since:

  1. I had a box of spare parts I wasn't using,
  2. I was planning on moving to a BrewPi-type setup later anyway, and
  3. I'm a fussy bastard who will almost always go the DIY route (even/especially if it's harder).

 

Rather than going with a simple, standalone temperature control setup, I grabbed an integrated arduino/ethernet board from another stalled project so I could use the networking capability to output data to the web (eventually I might add the ability to control it from the web too, but baby steps). Added two DS18B20 temperature sensors (one for ambient temps, one for fridge), built a small solid-state relay control board, and the first prototype was complete for a total cost to date of $14.

 

7zQHz03.jpg

 

Tested the stability of the system over a few days using a free web service to graph temperatures. Since the prototype was sitting on a desk in the study and the sensors were side by side, the plots came out identical, but the system ran for a few days without issue. First stage complete!

 

3AknHGC.jpg

 

Grabbed an enclosure from Jaycar (on clearance, woo!), and upcycled a spare 4-wire phone cable I had laying around for my remote/fridge sensor. The flat profile meant that it would sit nicely between the fridge body and seals without creating a large gap for the cool air to escape. Fitted it with a 2.5mm stereo jack and wired a 2.5mm socket to a DIY arduino shield made out of leftover protoboard/header pins. Signal/power connections for the relay board added too, but relay not connected to 230VAC yet (refer to relevant state laws, don't DIY 230VAC, etc).

 

ts7fIcR.jpg

 

Put the remote sensor inside the fridge and let the whole shebang run. Part of this was to get an idea of how cold the fridge could get, and the other was to get an idea of how quickly it could get to temperature. Console output tweaked slightly to give more meaningful feedback.

 

ND570IE.jpg

 

So the controller works, it's time to focus on the fridge. Since we already had two fridges when we were given this one, we never really needed to plug it in and thus never really cleaned it. Started by taking the door off, removing the thermostat and attacking it with a bottle of Jif and a scrubbing brush (much to my wife's surprise).

 

Oa2t0a8.jpg

 

With the fridge clean (I have no photos of this for some odd reason), I had a Fridgie mate pop around and check out the electrical work I'd done before powering it up (see above RE: relevant laws, don't DIY, etc). While the controller was working beautifully with the fridge, I was starting to have issues around this point with the data-logging/graphing service I was using -- it kept messing up timestamps and looping back on itself to try and correct the error. Tried a few different approaches before switching services to another freebie that ran a little more reliably (and with correct timestamps). The new data-logging service had the option to setup a widget I could watch from work to monitor temperatures, too. Nifty.

 

Filled the Craft FV with water and attached the remote sensor, which was insulated with part of a butchered stubby-cooler. Ran the system for a few days to check performance and consumption, which worked out to cost around 7c a day to run on average (at least with a setpoint of 22°, hysteresis of 2°, and ambient temps between 24-30°).

 

4xw2bH0.jpg

 

With the system & testing now complete, the first temperature-controlled brew is set to start sometime on the weekend. Hoping to remember to take a few more happy-snaps to update this post when it happens.

 

Total cost: $28 (enclosure + solid-state relay)

Total time cost: Not a great deal, but enough to have win over SWMBO with a bunch of flowers, a few nights in the kitchen and the promise of tasty beer.

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  • 3 weeks later...

Pardon the double-post -- having used the controller to fully ferment one batch, the ability to graph temperatures has enabled me to spot a noticeable difference in the temperature rise gradient between active fermentation and when the brew has pretty much reached FG (irrespective of ambient temperatures).

 

Since it's a given that active fermentation generates a slight amount of heat, the data nerd in me wants to try and derive some specific temperature rise formulas for my fermentation fridge based on ambient temps (when no fermentation is active), then to do the same for active fermentation to see what the difference is.

 

Fortunately though, the beer nerd in me has said that's a bit too much work for the silly season, and that checking SG every so often does the same thing, for way less effort.

 

Think the beer nerd might be the smarter of the two...

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Yup. I have to agree. Very good work.

 

I'm a bit of a gee-whizzo-techno-greek myself. I can almost make the hair straightener and dryer sing. I understand the knee bone is connected to the thigh bone, but what connects it to the backbone? And I know it must be a very sad time for you after your hysteresis, but after a while maybe you can adopt.

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Thanks gents! I'm already planning improvements to the current setup, so when all the ducks line up, I might share a few more happy-snaps and a bit of a write-up.

 

I know it must be a very sad time for you after your hysteresis' date=' but after a while maybe you can adopt.[/quote']

I almost spat my beer out when I read that, you funny b@stard... lol

 

You won't treat me like less of a woman now, will you?

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Pardon the double-post -- having used the controller to fully ferment one batch' date=' the ability to graph temperatures has enabled me to spot a noticeable difference in the temperature rise gradient between active fermentation and when the brew has pretty much reached FG (irrespective of ambient temperatures).[/quote']

Here's a visual of what I was blathering about -- this is for a mid-strength kit lager that should end around the 3.5% ABV mark (so logic says fermentation shouldn't take long anyway):

 

itNCKcu.jpg

 

You can see that it took around 8 hours for the yeast to rehydrate/wake up and start munching through the sugar, and the steep temperature rise gradients between pitching and around midnight on 29/30 Dec indicate that fermentation was kicking along nicely, after which point it slowed to a profile similar to the water tests I did before using it for brewing.

 

I haven't checked the SG to confirm yet, but since I'm planning on checking it later this afternoon, I'll go on the record as saying that I reckon it's already around the 1.008 to 1.010 mark (from an OG of 1.035) based purely on the temperature rise.

 

The next batch will be up around the 5-6% ABV mark, so it'll be interesting to see if I get a similar graph (though it'll obviously be a bit longer).

 

Late edit: Just checked the SG @ 19:53 and it's 1.010. Spot on.

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hey guys,I am looking for some help with temperature control. I have an old fridge/freezer that i would like to use as a brew fridge. I am considering the mangrove jacks controller just wondering if it will work plugged straight in or does the thermostat need changing? also wondering if it's a problem that it has a freezer compartment above. any help appreciated.

cheers

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G'day Scott,

 

I've got the mangrove jacks temp controller and it works great essentially it is the thermostat and switches it on if it gets to warm and off if to cold I have done lagers and ales and cold crashed with it and it has maintained temps perfectly.

 

Cheers

 

Oh and my fridge has a freezer up top to I don't use it I just ignore it could probably store some brew cans or something in it.

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I'm guessing the MJ temp controller is basically a re-branded STC-1000 or the like...anyway, the thing with these external temp controllers is described exactly by "external".

 

There is no need to fiddle with the fridge thermostat or anything like that. The controllers don't override it either. Plug the fridge into the controller and the controller to the mains, set your temps and leave it to do its thing. All they do is act like a person standing there flicking the power to the fridge on and off intermittently to maintain a certain temperature. You may notice if you open the fridge when the contoller has turned it off, that the light doesn't come on. This is why.

 

Obviously when running the fridge on its own like you would for normal foodstuffs in the kitchen or wherever, the fridge thermostat only controls when the compressor comes on and off to maintain its temperature; the power is constantly on.

 

Cheers

 

Kelsey

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  • 9 months later...

Hi All, Just wondering if anyone has any idea what the average temp difference would be between an insulated thermistor attached to the fermenting vessel (like mine pictures) and what the actual liquid temp is?

Ive installed an STC-1000 in this fridge and just curious how accurate it may be.IMG_2312_zpsics1jh53.jpg

 

thanks,

Ben

 

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In my experience it's accurate to about 0.5 of a degree going off SG samples taken and immediately measured with my mash thermometer. I do calibrate the STC 1000 every 3 or 4 batches against my other thermometer as well, just to make sure it's reading properly.

 

That's close enough for rock n' roll for me.

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In my experience it's accurate to about 0.5 of a degree going off SG samples taken and immediately measured with my mash thermometer. I do calibrate the STC 1000 every 3 or 4 batches against my other thermometer as well' date=' just to make sure it's reading properly.

 

That's close enough for rock n' roll for me. [/quote']

Yeh, still waiting for my thermalwells I ordered and going to attach to one of my FVs - to get close to the reaction center - just to see joyful

However I'm running out of beer because my brother found out! So I'll be brewing an ALE in the cellar.

Lager season is over for me until I get a fridge (mainly logistics and time) - but a proper thermal chamber like a fridge would provide better stats.

 

@benny:

Just an observation but probably not a big deal. I wouldn't place the heater pad in direct contact with the FV. Because it's already in a thermal containment - putting a couple of foam blocks between the pad and the FV would allow the heat to dissipate more evenly within the chamber. Temps will rise more slowly but be more consistent within the wort. I know some put the pad in a self below the FV shelf giving a least a couple of inches as it primarily usage is general chamber heating.

I don't have a chamber (fridge) but I still raise it on foam blocks + wrapped in a thermal blanket - holds it own - especially when the yeast is very active.unsure

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Yeah having a fridge certainly makes lager brewing a LOT easier given you have pretty precise temperature control at your fingertips. I didn't really brew any until I got the fridge to ferment in. And then I got annoyed at them tying up the fridge for 2-3 months at a time until I was put onto the quick lager method which turns them around in about 4 weeks. Needless to say I'm brewing a lot more of them these days. lol

 

Re the heater, depending on your location and/or the weather in general, you may not even need it in there at all. It's easy for me being in Brisbane because it rarely gets cold enough to need heating, especially during the height of fermentation. I've actually yet to bother with it. I don't get any real temperature overshoot downwards, maybe 0.1C if it's a little cool and nearing the end of fermentation (or during the lag phase) but otherwise it stays between 18 and 18.3 for ales. Lagers I never have any issues, with them being fermented at 10C.

 

The thing is, to maintain the fermentation temp, the air in the fridge is probably 2-3C lower than fermentation temp anyway, and the beer temp will take a lot longer to move down, plus the yeast is generating heat at the same time. That said, there are obviously situation where heating is needed, for instance in colder climates than mine.

 

Cheers

 

Kelsey

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Not that I have seen it happen, but have read that heat pads or belts designed for brewing, must be in contact with the fermenting vessel, to sink the heat generated by the pad or belt, otherwise they can melt.

 

The are also a lot more powerful than what is actually required when using a fridge as a chamber. My reptile heater seems to average only about 6 watts to heat my fridge to about 8 degrees above ambient, (during winter for brewing ales in my garage in sydney).

 

The reptile heater cord is also cheaper, got mine for $12 delivered I think, from ebay, local vendor.

 

I also use a computer fan to circulate air inside my fridges, whether heating or cooling.

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Not that I have seen it happen' date=' but have read that heat pads or belts designed for brewing, must be in contact with the fermenting vessel, to sink the heat generated by the pad or belt, otherwise they can melt. [/quote']

Yeah you absolutely right, I had a helt belt melt on me for real. No such problem with heat pads. A small computer fan or similar would be a good idea.

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In my experience it's accurate to about 0.5 of a degree going off SG samples taken and immediately measured with my mash thermometer. I do calibrate the STC 1000 every 3 or 4 batches against my other thermometer as well' date=' just to make sure it's reading properly.

 

That's close enough for rock n' roll for me. [/quote']

 

Thanks mate, I might get myself another thermometer and calibrate mine too.

0.5 is nothing to worry I guess.

 

@benny:

Just an observation but probably not a big deal. I wouldn't place the heater pad in direct contact with the FV. Because it's already in a thermal containment - putting a couple of foam blocks between the pad and the FV would allow the heat to dissipate more evenly within the chamber. Temps will rise more slowly but be more consistent within the wort. I know some put the pad in a self below the FV shelf giving a least a couple of inches as it primarily usage is general chamber heating.

I don't have a chamber (fridge) but I still raise it on foam blocks + wrapped in a thermal blanket - holds it own - especially when the yeast is very active.

 

Cheers, I will look at moving this around as mine is a heat pad. But as Headmaster noted and I also have 1st hand experience with a heat belt melting through the bottom of a another fridge I had a Kegking controller running on. I watched their youtube video and the guy demonstrates just throwing it into the bottom. Lucky I smelled something otherwise may have been a fire.

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Interesting read guys

Ive just started and I live in Melbourne so maintaining 18-22c isn't all that hard at the moment but I can see it will be when it starts warming up (yes sometimes it does get hot in Melbourne!). I have a heater for warming up (an inversion heater) and after much discussion and advice from Kelsey Im gonna get a belt heater too

But......I have an old fridge in the garage which we bought when friends were staying and we needed another, its just a fridge only and quite big (240ltr or so I would say) - its not being used at all so seems like a waste not to consider using it - also I could then leave my FV's in the garage instead of taking up space in the laundry.

 

But - I am no tech wiz by any stretch of the imagination and my DIY skills are limited to say the least! I googled the STC100 and say plenty on ebay and they seem cheap - but the instructions to wire it all up and set up look a bit challenging. Some of the pics look very technical too ! Who would I get to come in ado that bit for me? - an electrician? fridge repair person?

I like kelseys idea of having the fridge plugged into the temp controller and that plugged into the mains - seems the simplest of options. But does that still require wiring/set up?

 

What do you guys think?

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Very good idea to get that fridge going Payno, you will never look back.

 

You could just buy one of these already wired up:

 

http://kegking.com.au/mkii-10-30amp-temperature-controller-heat-cool.html

 

looks like this new one has programmable functions now. I could use one of these for automatic step mashing!

 

I'd go a 25W reptile heater cord over a heat belt though if using the fridge. Cheaper than a belt and you dont need to strap it to the FV.

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