New Fridge Fermentation Setup

[Metman79]

Hi there, next brew and all following, I will be aiming to be fermenting in a proper temperature controlled environment.

So I've gone down the popular route of 2nd hand fridge, greenhouse heater and Inkbird controller. So far so good but just getting things setup for brew day on Wednesday. Found a 2nd hand fridge freezer for £30 so trialling that, not the most efficient I guess due to the freezer element, but it's what I've got at the moment.

I've not gone through the drainage hole for the heating element yet due to needing to chop the plug off and rewire, so I'll probably do that next time. Mounted the heater to the door due to room issues having a 30L Speidel and the MASSIVE air lock that comes with it. Will try out next week and test and adjust as needed as I've just routed wiring via the door seal currently.

Any tips, comments welcomed as this is my first attempt at using this system.

 

[Galena]

Looks good to me apart from the cost of running the freezer if it's empty as you said.
How much space do you have above the top of your airlock? You could use a blowoff tube instead and then raise the FV a little on a platform and put the heater underneath then, also if you have the tap with that Speidel (great choice) then you can use that to take samples for hydrometer or refractometer.

 

[Metman79]

I'd like to try the airlock first, just for interest, otherwise yes plan would be for blow off tube or loose fitting cap on top. Otherwise Speidel too tall to fit a platform under, currently empty too (as photo) because I was just trialling to make sure fridge and heater worked. But the plan is to use the tap at the base which I bought as well when I ferment.

Additionally base temp was 16.5C before I started up today in the garage so the system should mostly be heating anyway. Might pop some bottles of water in the freezer just to get some cold water.

 

[Racehunter]

Just a point. If you are controlling cooling and heating through the inkbird, when it calls for heat, then the compressor will not run and the freezer section will defrost. If I remember correctly to have fully independent control between fridge and freezer, the FF would have to be a twin compressor type and even then would require the electrical circuits to be split somehow.

 

[Metman79]

Yeah, I think that's fine, especially as the garage is cooler than my fermenting temperature most of the time, so will be heating more than cooling. I'll probably plan to upgrade to a large fridge when I find one so that I'm not using the freezer section too. I don't want to mess around with electrics and splitting out circuits.

 

[chopps]

Keep your hops in the freezer part. Even though the fridge is cycling on and off there’s enough residual coldness in the freezer to stay below zero unless you’re opening it too frequently.

 

[Metman79]

We'll probably also use it as a spillover/back up fridge freezer over Christmas etc.

 

[Bill_g]

It would be worth checking whether the fridge and freezer have independent compressors. Low cost fridge freezers frequently do not. Assuming there are independent compressors then the only way that you will be able to use the fridge and freezer sections independently is to re-wire. Your Inkbird controller will just turn the mains supply on & off, so the freezer temperature will be all over the place unless separated out. Looking at my fermentation data logs I think it's a fallacy to think that you might not need cooling, the yeast generates quite a lot of heat during the rapid fermentation phase.
If you find that you have to run the freezer section then just fill it with bubble wrap or polystyrene insulation to prevent air convection.
You will find a lot of moaning about the reliability of tube heaters. I'm fairly certain that this is down to extreme temperature cyvling because the heater is not in good thermal contact with the main thermal mass i.e. the fermenter. A heater belt or mat is a better choice in my opinion because the temperature of the haater element will track the fermenter fairly closely putting less thermal stress on the heater internal wiring etc.

 

[Metman79]

Hey Bill-g, thanks for the feedback.

Nope, not independent compressors as it is, as you guessed, a low cost fridge. Good point on the heat put out through the fermentation process though, be interesting to see how much the fridge freezer has to cool to counter act this. Nice tip about filling the freezer part with bubble wrap, might try that.

I've got a couple of 25w heat belts that I've used in the past so could try that as an experiment on the next one and compare how stable the temperature was in both. Plan is to get the wort down as close to pitching temp (19°C) to start with to put less stress on balancing out the heater and cooler cycles. Will see how this pans out on Wednesday/Thursday.

Longer term plan is to get another 2nd hand large 'fridge only' when one pops up to remove the complications of the dual fridge freezer. This only cost £30 so will probably easily be able to pass on at some point.

 

[Bill_g]

You might find the images below interesting. The data output is from a PLAATO airlock, so the temperature shown is the temperature of the air at the top of the fridge cabinet, see photo. (The PLAATO airlock is mounted on a reservoir which prevents problems from excess krausen getting into the airlock). My temperature controller sensor is taped to the side of the SS fermenter. I allow something like +/-0.5C hysteresis to aim to hold the temperature to 18C +/- 0.5C. I don't set a compressor delay which if you have an Inkbird can also be set to avoid the fridge & heater cycling too rapidly.

The second image is the normal PLAATO app display and the third one zooms in on the cooling period which lasted a little over 24 hours. The temperature of the garage is currently 19C but will drop a bit overnight.
I guess the point I'm making is that the fridge cabinet acts as a pretty good insulator. You could just leave the door open but the point of using a fridge is to keep the fermentation temperature within a target range so I can't see much point in that approach. The brew belt heater being in good thermal contact with the fermenter means that its temperature tracks the fermenter, so will only drop a small amount when the fridge air temperature drops in the cooling phase. A tube heater positioned at the bottom of the fridge will experience a much greater temperature change and fairly rapid cycling between cooling and heating judging from the plots above.
Temperature cycling is a tough test of any electrical equipment. It could well be why many seem to report short lifetime of tube heaters. Also could be simply that they typically don't last long in any installation but I doubt that's the case. Not all fail quickly of course & some are reported to be years old & still going strong. So it's just something to bear in mind if failure occurs, not a reason to change anything now.

 

[Metman79]

Wow, thanks Bill_g, great post and info, I love how techy you can get with these things with the right equipment. I'm very interested to see how this goes as I've never attempted to precisely control my fermentation before. Might not help that I'm going slightly off-piste with an experimental recipe/brew, but interested to see how it all comes out and I'm pretty sure they'll be something drinkable at the end of it at the very least.

As I say this is all more of an experiment and familiarisation with the new equipment and process so will only get better/slicker the more brews I get under my belt. The next brew will involve looking in more detail at managing my water chemistry as well, but the water is pretty soft here so mostly with this 1st brew I'll just look at eliminating the chlorine.

 

[Theoriginalrich]

You might find the images below interesting. The data output is from a PLAATO airlock, so the temperature shown is the temperature of the air at the top of the fridge cabinet, see photo. (The PLAATO airlock is mounted on a reservoir which prevents problems from excess krausen getting into the airlock). My temperature controller sensor is taped to the side of the SS fermenter. I allow something like +/-0.5C hysteresis to aim to hold the temperature to 18C +/- 0.5C. I don't set a compressor delay which if you have an Inkbird can also be set to avoid the fridge & heater cycling too rapidly.


View attachment 45987View attachment 45988View attachment 45990

The second image is the normal PLAATO app display and the third one zooms in on the cooling period which lasted a little over 24 hours. The temperature of the garage is currently 19C but will drop a bit overnight.
I guess the point I'm making is that the fridge cabinet acts as a pretty good insulator. You could just leave the door open but the point of using a fridge is to keep the fermentation temperature within a target range so I can't see much point in that approach. The brew belt heater being in good thermal contact with the fermenter means that its temperature tracks the fermenter, so will only drop a small amount when the fridge air temperature drops in the cooling phase. A tube heater positioned at the bottom of the fridge will experience a much greater temperature change and fairly rapid cycling between cooling and heating judging from the plots above.
Temperature cycling is a tough test of any electrical equipment. It could well be why many seem to report short lifetime of tube heaters. Also could be simply that they typically don't last long in any installation but I doubt that's the case. Not all fail quickly of course & some are reported to be years old & still going strong. So it's just something to bear in mind if failure occurs, not a reason to change anything now.

Hi Bill. After looking at your photos I’m keen on finding out what you think of the Plaato. I have been close to buying one a couple of times but some reviews aren’t complimentary. Is it worth buying?

 

[Bill_g]

Hi Bill. After looking at your photos I’m keen on finding out what you think of the Plaato. I have been close to buying one a couple of times but some reviews aren’t complimentary. Is it worth buying?

I've got mixed feelings about it, at first I was a bit disapointed but I've now got it working a lot better and I think it does provide 'useful' fermentation info, but to be honest it's a brewing gadget rather than an essential tool. The main useful thing is that it provides a graphical log of the fermentation so it's possible to see when fermentation started, follow the rise in CO2 generation, make sure that the temperature reading is doing what's expected and finally see that CO2 production & therefore fermentation is finishing off. The calculation of gravity is a prediction and actually isn't far out, but can't replace a final hydrometer reading.
I found two major problems which I fixed with the CO2 tube & reservoir shown in the photo. Firstly if the fermentation is vigorous then krausen can find its way into the airlock. The bubble counter then stops working and so the log for that brew is useless. Also for PLAATO to be accurate it's important that there is no leakage of CO2 which can be a challenge for some types of fermenting vessel. The other thing to be careful of (but true for all air locks I guess) is that a cold crash or drawing liquid out of the tap on the fermenter will cause the airlock water to be drawn back into the fermenter. For PLAATO you can't use sanitiser because any foam mucks up the bubble counting mechanism.
But overall, having got it working and understanding its foibles, I like to be able to monitor the fermentation progress on my smartphone so I'm fairly happy with it. However if I had more head room in my fermenter I probably would have gone for a tilt hydrometer or iSpindle. Indications are that these should work ok inside SS fermenters because the various gaps in the metalwork are quite 'leaky' for radio waves.

 

[Metman79]

Thought I'd send a quick update to let you know how it went. I've been using the fridge for the primary ferment and I was actually struggling to get the wort down quickly to pitching temperature in the Brewzilla, despite having a pump/whirlpool going at the same time as having the immersion chiller in. So pitched slightly higher in the end (22°C) but then quickly brought it down to 19°C in the fridge. The fridge seemed to maintain the temperature nicely and the door stayed shut fairly well, despite the gap where the cabling exited.

Bought the temp up to 22 then 23°C after 4 day, which again held really well mostly using a little burst of heat every now and then when the temp dipped and now just over a week in, am cold crashing. It's been 24hrs and so far the fridge is only down to 9°C from 23°C and I've set the InkBird to 5°C so we'll see if I can actually reach that overnight toight. Possibly cold crashed too soon given I went from 1055 to 1013, it should really be finishing around 1011, but too late to change that now and I may just adjust the amount of priming sugar a touch just so there's not chance over over-carbonation. Lessons for next time!

Overall, I think it's worked out well but I'd prefer a straight fridge if I can get my hands on one, more for efficiency on the cooling cycle. So will keep my eyes peeled and see what crops up. Will perhaps also try with the heat belt instead of the current heating element, although no real issues so far on that front, but wiring easier to take care off through the drain outlet with a heating belt.

 

[Buffers brewery]

Sounds like it went well.

Possibly cold crashed too soon

I measure the SG after 10 days and again at 12 days. If they’re the same, fermentation is finished. If not repeat in a couple of days until the two subsequent readings are the same then you can confidently start cold crash. If you don’t want to take lots of samples leave it for 14 days before taking the first sample.

 

[Metman79]

Yep, that's the plan next time. Previously everything has been a little adhoc with my brews, trying to get a bit more technical as my experience grows.

 

[Metman79]

Sounds like it went well.



I measure the SG after 10 days and again at 12 days. If they’re the same, fermentation is finished. If not repeat in a couple of days until the two subsequent readings are the same then you can confidently start cold crash. If you don’t want to take lots of samples leave it for 14 days before taking the first sample.

Does this is also partly depend on how active your yeast is and therefore every brew is going to be different? I pitched with Lalleman's Verdant, which is supposed to be pretty active and can finish in 5 days or so?

 

[Buffers brewery]

Does this is also partly depend on how active your yeast is and therefore every brew is going to be different? I pitched with Lalleman's Verdant, which is supposed to be pretty active and can finish in 5 days or so?

Experience will eventually guide you. I used Verdant for the first time my last brew and yes, it was all done in a week and I kegged it after 12 days including 4 days cold crash. Other yeasts are slower but the 2-2-2 rule is a pretty good place to start...2 weeks ferment, 2 weeks carbing and 2 weeks conditioning after bottling or kegging.

 

[Metman79]

Thanks BB, great advice on the 2-2-2 rule, I'll definitely bear that in mind in future. Sounds like you had similar timings with Verdant so fingers crossed this will all work out okay. Looking forward to the first taste further down the line once the bottling, carbing and conditioning have finished....still 4+ weeks away!!! Patience is a virtue I guess

 

[Metman79]

PS -fridge took 2 days in the end to cool 23L from 23°C to 5°C, but it's sat there holding temperature nicely now.