[Herminator]

I recently brewed up a belgian dubbel and pitched Wyeast 1214.  Fermentation took off in about 12 hours and has been rather active.  Smells like someone is baking banana bread in the fermentation chamber.  Anyways...I have the chamber at 72 ambient temp, but am a little concerned about fermenting too high with fermentation action inside.  Based on what I have read, that could reach 10 degrees higher....which would put me at much higher than suggested temps.

So, my question.  What do people do to measure the actual temp. of the wort? So, what are other people doing besides just a temp sticker on the side?  Anyone have good luck with thermowell?

Thanks. 

[morticaixavier]

thermowells are great but I have always been happy with the stick on fermentometer. I will say that 72 ambient is a bit too high already. I like to keep my ferm chamber around 64 for the beginning of most, if not all ale ferments. Some, like kolsch I will actually go lower.

With Belgians, big beers, and saisons I will bump the temp up to 74 after the first 3-4 days and turn off the temp control (or turn on heat) at the very end aiming for 78ish. some saison strains obviously like it a lot warmer but I often get a fusel headache when I drink homebrewed saison and I suspect the 'wisdom' of the high ferment temp.

[Herminator]

Thanks for the suggestion.  I know that wyeast suggests 68 degrees at the lowest for this strain and thought I was doing alright with keeping it at middle range (68-75), but then became concerned about the active fermentation temp inside.  Hopefully I haven't pushed this too high (80) active fermentation temp. I think i may just have to tape my probe to the side and see what it says. 

Thanks. 

[morticaixavier]

Thanks for the suggestion.  I know that wyeast suggests 68 degrees at the lowest for this strain and thought I was doing alright with keeping it at middle range (68-75), but then became concerned about the active fermentation temp inside.  Hopefully I haven't pushed this too high (80) active fermentation temp. I think i may just have to tape my probe to the side and see what it says. 

Thanks.

take those suggestions from the lab with a grain of salt. especially the low end. but even if you want to keep it in the suggested range, aim for the low end.

[HoosierBrew]

Thanks for the suggestion.  I know that wyeast suggests 68 degrees at the lowest for this strain and thought I was doing alright with keeping it at middle range (68-75), but then became concerned about the active fermentation temp inside.  Hopefully I haven't pushed this too high (80) active fermentation temp. I think i may just have to tape my probe to the side and see what it says. 

Thanks.

take those suggestions from the lab with a grain of salt. especially the low end. but even if you want to keep it in the suggested range, aim for the low end.

For sure.  I've used 1214 many times and I think that pitching at ~ 64F , holding for 2-3 days, then slowly ramping up until completion gives by far the best results. That comes after fermenting it too warm a time or two and getting giant banana bombs. +1 to taking the fermentation temp ranges (low end especially) with a big grain of salt.

[Joe Sr.]

As far as temp measurement, the stick on thermometers are pretty accurate.

No need to over think it.

FWIW, if you ferment too high and get fusels it is possible that they may age out.  If you have the space and can store the beer it would be worth it.

I've had a couple batches in recent years hit the mid to upper 70s on fermentation temps  and did not experience any excessive fusel production.  It is/can be very yeast dependent.

[corkybstewart]

I use a thermowell in my conical and love it.  I will say that the stick on thermometer usually is about 4 degrees higher than what the digital readout on my temp controller says.  Maybe I'm wrong but I trust the digital more than the $2.00 stick-on.  The thermowell and temp controller are much more precise than me constantly having to read the thermometer and adjust ambient temp as fermentation activity peaks and then subsides.  Set it and forget it!!!
BTW I made my thermowell from the diptube of an old rusted out keg that someone gave me so it was essentially free.  I just folded the bottom end over a couple of times and beat it with a hammer so that it's completely watertight.

[a10t2]

I will say that the stick on thermometer usually is about 4 degrees higher than what the digital readout on my temp controller says.  Maybe I'm wrong but I trust the digital more than the $2.00 stick-on.

I'm the opposite... There's much more that can go wrong with a digital thermometer.

Either way, I think you need to calibrate them both.

[denny]

Thanks for the suggestion.  I know that wyeast suggests 68 degrees at the lowest for this strain and thought I was doing alright with keeping it at middle range (68-75), but then became concerned about the active fermentation temp inside.  Hopefully I haven't pushed this too high (80) active fermentation temp. I think i may just have to tape my probe to the side and see what it says. 

Thanks.

Forget what they recommend and trust your senses and experience.  I've found that if I run that yeast above 65F, I get so much bubblegum and banana from it that I can hardly drink the beer.  Your tastes may be different, but trust yourself, not what the yeast companies say.

[hubie]

Based on what I have read, that could reach 10 degrees higher....which would put me at much higher than suggested temps.

I keep hearing that 10 degrees, and sometimes it is 5 degrees, but it always anecdotal.  I suppose at some point I will set up my own experiment, but with all the agitation going on in the fermentor from thermal gradients and CO2 production, during active fermentation I can't see how there is going to be significant differences in temperatures anywhere in the beer.  The difference in temperature between a thermowell and something on the outside of the fermentor will strongly depend upon the type of device and how it is mounted.  A hard cylindrical temperature probe (like from a Ranco controller) makes horrible physical contact (almost no surface area contact) with the cylindrical wall of the fermentor, so it is important to cover them well with an insulator (bubble wrap) and lots of tape because the probe will measure the temperature of the air around it better than it will measure the temperature of the fermentor.  A stick-on thermometer makes great contact with the fermentor via its adhesive, but you're relying on something that has one side exposed to the air and the other side that has a thermal insulator (glass/plastic) between it and a large thermal mass (beer).

As Sean says, if you really want to know, you need to calibrate them, but make sure you calibrate them like you will use them because you might find the stick-on ones have one offset when on a glass carboy, and another when on a plastic carboy or bucket.  The good thing about all of this is that if you set everything up the same, you'll get consistent results.  You need to keep in mind that if someone says they get great results fermenting at 64F, not knowing how they are measuring temperature and what their offsets are, that might not be the same 64F to you. (Yeah, I know, I hate those "it is different from system to system" answers too...)

[morticaixavier]

Based on what I have read, that could reach 10 degrees higher....which would put me at much higher than suggested temps.

[...]
I keep hearing that 10 degrees, and sometimes it is 5 degrees, but it always anecdotal.  I suppose at some point I will set up my own experiment, but with all the agitation going on in the fermentor from thermal gradients and CO2 production, during active fermentation I can't see how there is going to be significant differences in temperatures anywhere in the beer.  [...]

I think the 10 degree variance in questions is the one between the beer (as you say, anywhere in the beer) and the ambient temperature of the fermentation chamber.

Other than that +1 to your points.

[Herminator]

All really great feedback.  Thanks everyone.  This is my first attempt at a Belgian and knew I could maintain the higher temps...but then spaced on the fermentation temp increase.  This might end up being a brew that would have better inside where it is a little cooler.

Either way, I have learned a lot with this brewing and fermentation process.  While I am a fan of bananas...not sure if I want a bottle of them.  Oh well, only time will tell. 

Thanks again everyone.  I will have to figure some stuff out in my fermentation chamber. 

[Jimmy K]

My thermometer has a probe and an infrared reader. IR is more of a toy than truely useful in brewing, but it does read the temperature of beer through a glass carboy pretty well. I've been using it for that a lot.

[klickitat jim]

Another way is to figure out what ambient temps work for you and stick with them. I know that I've been slowly lowering my chamber temps to hit what I like. Currently I brew with 1056 at 62° ambient. Probably about 65 ish actual

[a10t2]

I keep hearing that 10 degrees, and sometimes it is 5 degrees, but it always anecdotal.

If you do the stoichiometry for how much energy is released during fermentation, transferred over the surface area of a 5 gal bucket or carboy in air, it works out to a 3-6°F average differential over 72 hours of fermentation, depending on fermenter material, humidity, airflow, etc. 5-10°F at high krausen seems totally reasonable to me.