Fermenters and fermentation fridges!

[kevin1911]

Afternoon folks! I'm looking to get a bit more control over the fermentation of my BIAB brews. I'm currently fermenting in one of those £20 plastic tubs with sealing lid and airlock, and have been leaving it in the corner of the kitchen during the fermentation period. The temperature of the kitchen swings quite wildly in the winter (~13C to ~20C at various times of the day), and is likely to be ~15C - 28C in summer. So I have acquired a large freezer and an Inkbird ITC-308 with a few to setting up a fermentation fridge to keep a constant temperature, and to allow me to start trying out some lagers.

I've seen a lot of debate about whether the thermometer on the ITC should be in the wort or in the air next to the FV. Is there any consensus amongst you guys about which is best? I'm concerned about hysteresis. Also, which heating element is recommended? It's a fairly tall freezer, but quite narrow.

Finally, I've been eyeing up those Brewtech SS Chronical fermenters, and like the idea of using something a bit more sophisticated. They're a little pricey though. Are there any FVs people recommend that are better than plastic buckets but not as expensive as those?

Thanks!

K

 

[MyQul]

You could possible use a fast ferment conical. Here's Godsdog's review http://www.thehomebrewforum.co.uk/showthread.php?t=58536 or go all American and get a glass carboy http://www.geterbrewed.com/5-gallon-glass-carboy/

 

[Leon103]

Is it a fridge or freezer?

I attach my probe to the side of the fv with a layer of bubble wrap Inbetween. I have check this temp again temp of the wort and they are very similar

 

[chuffer]

Does your inkbird have the long probe? If so, drill hole in FV lid and feed probe through lid after fitting a tight fitting grommet

 

[Graz]

As above, got mine taped to the side of the FV with a pocket of bubble wrap taped over that. Doesn't seem to swing around much on the default settings.

At the moment the heater warms it up to 20 degrees, then given it's colder than that in the garage it slowly drops to 19.5 degrees and then the heater kicks in again.

Got my heater here: http://www.ebay.co.uk/itm/Tubular-h...houses-/121067066775?var=&hash=item61d13d56fe

 

[Brewdoug]

I'm assembling my own brew fridge at the moment and I'm still undecided on whether to tape the sensor to the fermentation vessel or not.
I'm fully open to correction on this, but due to the time delay in the volume of liquid adjusting temperature to the surrounding environment, I can imagine it's temperature continually 'hunting', swinging one way then the other.
So why not just keep the environment in the fridge at the required temperature, making a small adjustment in the early stages of fermentation to allow for the heat created by the fermentation?

 

[kevin1911]

Cheers all. I'd seen those fast Ferment conicals and quite like the idea, but surely if it's plastic it still has the same drawbacks as plastic buckets?

I hadn't actually considered the glass carboy. I'll definitely look into that option.

It's the short, stubby probe on my Inkbird - I'll use the bubble wrap idea, seems least hassle. Isn't there quite a lag though between the heater kicking in and the liquid reaching the right temperature? Is the trick ensuring that the liquid is as close as possible to the ideal temperature before putting it in the freezer?

 

[Graz]

I'm assembling my own brew fridge at the moment and I'm still undecided on whether to tape the sensor to the fermentation vessel or not.
I'm fully open to correction on this, but due to the time delay in the volume of liquid adjusting temperature to the surrounding environment, I can imagine it's temperature continually 'hunting', swinging one way then the other.
So why not just keep the environment in the fridge at the required temperature, making a small adjustment in the early stages of fermentation to allow for the heat created by the fermentation?

Quite the opposite in my limited experience. When I'd finished my brew fridge I gave it a little test run with nothing in it. It was all over the show, heater on 20 degrees, heater off, temp continues to rise 21-22 degrees, fridge kicks in, down to 20, fridge off, continues to drop, etc. You get the idea.

I think that the large thermal mass of 23l of wort makes the whole process quite controllable as it is very slow to react. At the moment it's cold enough in my garage that it's only heating. The temp drops to 19.5, the heater kicks in and brings it up to 20, it may overshoot a little after that but as everything is now cooling off again it's never enough of an overshoot to cause the cooling to kick in.

Remember also the heaters we use in these things are really puny, only 60W at the end of the day, it would have to be on for quite a long time to make even a 1 degree rise to happen in 23l of liquid.

 

[Leon103]

Cheers all. I'd seen those fast Ferment conicals and quite like the idea, but surely if it's plastic it still has the same drawbacks as plastic buckets?

I hadn't actually considered the glass carboy. I'll definitely look into that option.

It's the short, stubby probe on my Inkbird - I'll use the bubble wrap idea, seems least hassle. Isn't there quite a lag though between the heater kicking in and the liquid reaching the right temperature? Is the trick ensuring that the liquid is as close as possible to the ideal temperature before putting it in the freezer?

The trick is getting the settings on the inkbird. I set it .3 either side so the heater or fridge kicks in early enough

 

[Brewdoug]

Quite the opposite in my limited experience. When I'd finished my brew fridge I gave it a little test run with nothing in it. It was all over the show, heater on 20 degrees, heater off, temp continues to rise 21-22 degrees, fridge kicks in, down to 20, fridge off, continues to drop, etc. You get the idea.

I think that the large thermal mass of 23l of wort makes the whole process quite controllable as it is very slow to react. At the moment it's cold enough in my garage that it's only heating. The temp drops to 19.5, the heater kicks in and brings it up to 20, it may overshoot a little after that but as everything is now cooling off again it's never enough of an overshoot to cause the cooling to kick in.

Remember also the heaters we use in these things are really puny, only 60W at the end of the day, it would have to be on for quite a long time to make even a 1 degree rise to happen in 23l of liquid.

Ah I see what you mean.

It's taken me a while to final finish my fridge off and test it out. Tried it with just the probe loose in the fridge and temperature set to 20 C with a 1 degree differential either way. The temperature swung all over the place, overshooting and undershooting, due to the heater and chiller maintaining their respective temperatures for a long time after switching off.
This means that either the heater or the fridge would be on almost all the time, making it rather expensive to run over 2 weeks fermentation period while not achieving the steady temperature I'm looking for.
So it looks like I'll definitely go with taping the probe directly to the fermenter covered with bubble wrap or something.

What temperature differential values do people generally find work best?

 

[dan125]

What temperature differential values do people generally find work best?

I have mine set to smallest possible differential of 0.3C with the sensor strapped to the FV under bubble wrap, and it works a treat.
If I have bottles carbing in the top, and there's no FV in it for a day or two, I leave the sensor dangling and increase the diff to 0.5.

 

[ericmark]

For heating using the probe held on the side of fermentor with some insulation I use a sponge is good enough, I tested with second probe centre of brew less than 0.5ºC difference so not worth the problem of sanitising the probe may as well go on side, the main thing is to use a small heater, I found an 8W bulb even in heart of winter was enough. I used it in freezer compartment laying on a tin tray so it would not damage plastic in the short draw, then I put the stuff to brew in the long draw, it will just fit the fermentor with no air lock fitted. During the winter I can do two brews one in fridge and one in freezer compartment.

In the summer it is another story, the freezer motor as around 85W and far more efficient than the heater I use, and this is the problem it is too big, so with the sensor on the fermentor the cooling will over shoot. What you need is around 3 to 5ºC between freezer switching on and heater switching off, but still 0.3ºC freezer switching on to freezer switching off. However the STC 1000 I use changes the gap between heating and cooling at the same time as the gap between cooling starting and cooling stopping. I also have a MH1210A which is very like the STC 1000 and I use one in top fridge and one in bottom freezer in winter. In the summer however both are used in the freezer one does heating the other does cooling so I can get the gap I need between heater off and cooling on. So I can still put sensor onto the fermentor.

However my experiments showed you can get a 3 ~ 5ºC variation between air temperature and brew temperature. How much depends how you heat the brew, I use a demo under floor heating panel 18W and this heats the fermentor direct, one way to reduce the variation is to use a fan, and I think most who heat and cool do have a fan running to help the heat transfer from air to fermentor or fermentor to air.

To my mind it is the fermentor temperature which is important, so side of fermentor is best, however having the heater and cooling playing yo-yo with each other is clearly not good, so in the summer either two controllers (or a really good controller) or measure air and use fan, in the winter with just a heater then on side of fermentor and use a small heater, as I say I found 8W CFL was ample.

As a PS today set up new brew with just cooling no heater, and on side of fermentor, I hope the freezer will never switch on but should it get too warm then it will stop it raising to some silly high level.