controlled fermenting..

[loady]

I am starting on converting a spare fridge into fermenter and just wondered by what means people control the temp. Having used a kegerator for some time, i initially had a probe sealed inside a vessel of water inside the kegerator, i found the the fridge/heater would contanly be fighting each other, even with the STC1000 set and many variation, i would still have to tweak it when the ambient temperature in the outhouse changed dramitically..i the removed the probe from vessel of water and left inside the fridge not touching anything and have found that to be the best way. My thoughts on that are that if the fridge is closed overnight then the beer would reach its stable temperature, if you had the door open for say 10 mins it would have no effect on the temperature of the beer as the fridge enviroment would restabilise within 4 minutes..doing it this way i found that only one element would ever be running..during the summer..just the cooler will run..during the winter just the heating element. I am hoping that the same will apply to the fermenting fridge i create.

 

[Dave1970]

I'm a probe in a pocket of bubble wrap on the side of the FV man. Don't seem to have any problems with the fridge & heater competing

 

[PD]

as above, I also try not to open the fridge doors too often...leave well alone when you know its fermenting well.

My shown temp remains in the range of 1C above or below the set temp, usually at it.
Very happy with that set up

 

[loady]

are your fermenting fridges situated in a constant ambient temp and are you using a PID or STC1000 as the controller ?

 

[Dave1970]

Using an STC-1000 and it's in an outside garage so the ambient is all over the place

 

[evanvine]

I have voted the way I would do it if I used a Fermenting fridge (option 3).
Alas my fermenter is too big for a domestic fridge or freezer.
So using a "Rab Maxwell" device and a thermowell for the probe, I directly heat/cool the wort.

 

[TheMumbler]

I just hang mine off the handle of the FV as I like to make sure that the probe is in the fridge. My fridge is indoors so the ambient temperature outside the fridge doesn't change very quickly.. My wort is generally more or less the same temperature as the temperature of the fridge interior when I take hydrometer readings but I suspect it will differ from the ambient temperature of the fridge more when fermentation is going strongly. I usually ferment towards the lower end of recommended temperatures for the yeast which I hope will keep things within ideal range when the FV is throwing off a lot of heat. I then move the temp up a bit later in fermentation. Say start at 17.5 on the STC1000 and then move it to 20.0 when fermentation is getting towards the end say 3 or 4 days after pitching when using S04 which has an ideal range of 15-24 according to Fermentis.

I think the best way of doing it would be to have your probe in the wort and to have some sort of heating/chilling coil also in the wort. You could also monitor the temperature more carefully this way if you had the right probe especially if you linked it up to some sort of computer.

The bottom line for me is I think I get better results using the fridge as I do than fermenting without any control and I don't have the time, expertise or inclination to set up a within wort system. If I had more time, space and money I might well start doing some more careful monitoring and control of fermentation using an in-wort system, just out of interest. However I won't be doing that for the foreseeable future.

 

[pjc]

I'm probably taking this a bit too far but over the last 2 weeks I have been monitoring four different temperatures in my garage and brew fridge using min/max thermometers. I have a standard set-up with a large fridge, STC-1000 and a heater under the FV. The STC-1000 is set to 19.5C with 0.5 range and the sensor is taped to the side of the FV under bubble wrap. Results are:-

1. The min/max temperature in the garage has been 13/27C
2. The min/max temperature of the air in the fridge has been 15.5/18.9C
3. The min/max temperature of the beer in the centre of the FV has been 18.4/18.5C
4. The min/max temperature of the STC-1000 probe location has been 19.1/19.8C

So very stable beer temperature. I'm going to try it with the sensor just hanging in the air next time and see what happens.

 

[graysalchemy]

Very stable indeed PJC however it still means that by taping the sensor of the STC to the outside of the FV means that there's still a discrepancy between what you think you have and control and what you actually have inside the beer.

Surely it is just as easy to stick the temp probe in the wort? thats what I do. :thumb:

 

[Baldbrewer]

Probe wrapped in bubble wrap sat on a bracket at a level of 2" above base of FV.
Never had any Fermentation issues :thumb:

Brews ranging from multi temp stepped weissbiers to sweet stouts and old ales.

 

[pjc]

Surely it is just as easy to stick the temp probe in the wort? thats what I do.

I agree graysalchemy although it would appear that there are temperature variations going on inside the beer between the centre and the edges of the FV which I suspect will be present regardless of where the probe is placed. So it's just a question of which temperature you want to control; the centre or edge.
Anyway, it's probably not worth worrying about too much. As long at the beer doesn't hit 27C. :thumb:

 

[TheMumbler]

Surely it is just as easy to stick the temp probe in the wort? thats what I do.

I agree graysalchemy although it would appear that there are temperature variations going on inside the beer between the centre and the edges of the FV which I suspect will be present regardless of where the probe is placed. So it's just a question of which temperature you want to control; the centre or edge.
Anyway, it's probably not worth worrying about too much. As long at the beer doesn't hit 27C. :thumb:

I'm wary of putting the probe in the beer using the plastic probe that came with my stc1000 since lancssteve lost a couple of batches of beer due to an infection that got carried on his similar probe. Since I've never had any quality issues (so far as I can tell!) with the outside the bucket method I prefer not to take the risk.

 

[Aleman]

I heat and cool the wort directly so measure the wort temperature with a probe in the wort.

If I was using a brewing fridge, then I would probably control the fridge temp with an STC monitoring the air temp . . . although I would still heat and cool the wort directly and therefore have another STC controlling that . . . Sound like something that should be controlled/measured with a Arduino and a Pi . . . . :whistle: :whistle:

 

[graysalchemy]

Anyway, it's probably not worth worrying about too much. As long at the beer doesn't hit 27C. :thumb:

Well it does matter, 22c is probably nearer the mark for critical temp than 27c, and the difference in beer profile between 21c and 18c can be quite significant. If I want a nice fruity bitter with plenty of esters you need to hit 21c in the initial stages of fermentation, go over and you start running the risk of fusels (fusels and ester production are very closely linked)

 

[anthonyUK]

I've measured the various temps in the past and there is little difference between wort and FV

The probe should be attached to something with a thermal mass to stop this which shows even with a small amount of liquid the variation is reduced.

Live temps

 

[pjc]

...the difference in beer profile between 21c and 18c can be quite significant.

So if there is a temperature gradient between the centre and edge of the beer in the FV then my results might suggest that putting the probe in the beer might make that gradient steeper. I have a variation of 1 degree at the edges which produces a variation of 0.1 degrees in the centre. If you put the probe in the beer then even at the lowest resolution of the STC-1000 of +/- 0.1 degrees then you are only going to be able to control the temperature with a variation of 0.2 degrees and presumably the edge temperature is going to swing about more than 1 degree.

 

[winelight]

1. The min/max temperature in the garage has been 13/27C
2. The min/max temperature of the air in the fridge has been 15.5/18.9C
3. The min/max temperature of the beer in the centre of the FV has been 18.4/18.5C
4. The min/max temperature of the STC-1000 probe location has been 19.1/19.8C

Interesting, and I note your point about measuring the wort temperature will automatically double the swing shown in 3.

I'd like to see what the results are with the STC probe in the fridge airspace.