How are most people here measuring their fermetation temperature?

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Nick_D
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How are most people here measuring their fermetation temperature?

Postby Nick_D » Sat Oct 15, 2016 3:51 pm

Rather than post this in my 'never ending story' of cold fermentation woes, I thought it might deserve its own thread as it may be helpful to others in the future.

How are most people measuring their fermentation temps ? I see Brandon for instance has a sleeve of insulating material, and slides his probe down there to measure the keg wall temp.

I have a thermowell that protrudes into the centre of the fermenting beer, and reads the temp at the heart of it. I constantly take readings of the internal temp, and adjust the ambient carefully to juggle the desired temp. What I have observed, is that there can be a difference between wall temp, and temp in the centre of the liquid, of up to 1C (1C warmer in the centre), or possibly more. My fermenter is about 11 inches in diameter, so quite a bit wider than a corny keg, which is no doubt exaggerating the temp difference between wall and centre.

Prior to attempting the cold ferment method, I had my temp probe stuck to the fermenter wall, under a bunch of foam to insulate from the ambient fridge temp. This previously gave me good results, so I am now questioning the thermowell, and wondering if I should return to a set up similar to Brandon's.

For example, to maintain 8C in the centre of the beer, I need to run an ambient temp of about 6.7C. Obviously the yeast on the outside closest to the fermenter wall will be less unhappy, and progressively happier towards the centre where it is warmer.

What are people's thoughts ?

P.S my thermometer is accurately calibrated.
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Brandon
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Re: How are most people here measuring their fermetation temperature?

Postby Brandon » Sat Oct 15, 2016 4:10 pm

I ran a few tests while I was getting my setup going. It is entirely possible/likely that fermentation temps are different in the center of the fermentation vs the wall of the fermenter. That said, fermentations have all gone to completion pretty well. One of the next things for me to tackle is fermentation to not just reach FG but also subtly influence flavor. I would like to try a thermowell but out of convenience and an easy solution to get started with I just went with the insulation and probe on the outside.

I believe Bryan uses a thermowell in his fermenters and likely gets more accuracy than me.

Then there's the line of thinking that precision is more important than accuracy and reproduceability is key over hitting a specific actual temperature.

Brandon
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Nick_D
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Re: How are most people here measuring their fermetation temperature?

Postby Nick_D » Sat Oct 15, 2016 4:22 pm

Brandon wrote:I ran a few tests while I was getting my setup going. It is entirely possible/likely that fermentation temps are different in the center of the fermentation vs the wall of the fermenter. That said, fermentations have all gone to completion pretty well. One of the next things for me to tackle is fermentation to not just reach FG but also subtly influence flavor. I would like to try a thermowell but out of convenience and an easy solution to get started with I just went with the insulation and probe on the outside.

I believe Bryan uses a thermowell in his fermenters and likely gets more accuracy than me.

Then there's the line of thinking that precision is more important than accuracy and reproduceability is key over hitting a specific actual temperature.

Brandon

Thanks for the reply Brandon. I'm trying to track down all the things that could be giving me grief recently. The three things I changed when going into the world of cold fermenting were 1: started using thermowell, 2: pure oxygen (but no DO meter), 3: using RO water, where before I'd use bottled spring water.
I've abandoned the pure oxygen until I can get a DO meter, and now run a few hours of sterile air through a 2 micron stone, and with the RO water I'm now adding yeast nutrient, which I wasn't before. That leaves the thermowell as possible conspirator. I wonder if my ferment temps have been a bit on the screwy side. Perhaps I'll give the old sponge/foam on side of fermenter a go and see what happens. Maybe I've been trying to ferment too cold by accident by reading only the highest temp location.
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Ancient Abbey
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Re: How are most people here measuring their fermetation temperature?

Postby Ancient Abbey » Sat Oct 15, 2016 6:25 pm

Ranco probe directly in a thermowell.
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Brandon
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Re: How are most people here measuring their fermetation temperature?

Postby Brandon » Sat Oct 15, 2016 8:07 pm

Nick_D, what controller are you using? Ancient, it looks like you're using a Ranco. which is what I used to use. The BrewPi vs Ranco might provide the same level of accuracy, but the BrewPi does great graphing of multiple data points (freezer, fermenter, +1 - room, heater, whatever) along the way. I feel like that gives a more rounded picture and you can 'see' the heat generated by fermentation by the BrewPi adjusting heating or cooling to compensate. Something to consider as I find it to be an order of magnitude better resolution of information.

As an aside, I did a Zero wort aeration fermentation with yeast that was at high krausen and it knocked it down fine. So aeration may not be as much of a factor.
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Re: How are most people here measuring their fermetation temperature?

Postby mchrispen » Sat Oct 15, 2016 9:49 pm

I have SSBrewTech Chronicals and a MoreBeer Conical - both have thermowells. So temp probes inside the fermenting beer. When I use my Spiedels for smaller batches, I tape the probe to the side and expect to set the temp controller slightly lower to account for the delta.
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Weizenberg
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Re: How are most people here measuring their fermetation temperature?

Postby Weizenberg » Sun Oct 16, 2016 4:21 am

One thing I notice is that you are unable to measure the oxygen content. When I got my DO meter years ago, I was surprised how big the variations can be. For example, not mixing the o2 well enough won't do it much good either. I noticed dead spots, I noticed how easy it is to not provide enough o2 or overshoot.

In short, you are flying blind.

Now, you don't have to have a DO meter. But then you don't have to attempt the advanced stuff either.

For a decent cold fermentation all your variables need to be correct. Before I had a DO meter my attenuation was always lower than when I started to measure and have an idea what was actually going on.

It's time to get the right equipment. Maybe you can borrow one?
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Nick_D
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Re: How are most people here measuring their fermetation temperature?

Postby Nick_D » Sun Oct 16, 2016 7:41 am

Brandon wrote:Nick_D, what controller are you using? Ancient, it looks like you're using a Ranco. which is what I used to use. The BrewPi vs Ranco might provide the same level of accuracy, but the BrewPi does great graphing of multiple data points (freezer, fermenter, +1 - room, heater, whatever) along the way. I feel like that gives a more rounded picture and you can 'see' the heat generated by fermentation by the BrewPi adjusting heating or cooling to compensate. Something to consider as I find it to be an order of magnitude better resolution of information.

As an aside, I did a Zero wort aeration fermentation with yeast that was at high krausen and it knocked it down fine. So aeration may not be as much of a factor.


Hmmm, well I don't have an automated setup like most here, Brewpi's and such. Just an STC-1000 with 0.1 C temperature resolution. I'm plagued with having to make all my inputs manually. So I'm johnny on the spot. I set alarms to tell me to adjust 0.2 up or down depending on what phase of fermenting I'm supposed to be in.
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Nick_D
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Re: How are most people here measuring their fermetation temperature?

Postby Nick_D » Sun Oct 16, 2016 7:49 am

Weizenberg wrote:One thing I notice is that you are unable to measure the oxygen content. When I got my DO meter years ago, I was surprised how big the variations can be. For example, not mixing the o2 well enough won't do it much good either. I noticed dead spots, I noticed how easy it is to not provide enough o2 or overshoot.

In short, you are flying blind.

Now, you don't have to have a DO meter. But then you don't have to attempt the advanced stuff either.

For a decent cold fermentation all your variables need to be correct. Before I had a DO meter my attenuation was always lower than when I started to measure and have an idea what was actually going on.

It's time to get the right equipment. Maybe you can borrow one?


I agree. It's quite frustrating to be left with a variable I simply can't currently knock down, and I appreciate everyone's patience in being so helpful despite this. The only person I know with access to a DO meter, is a PhD researcher friend who works in a biology lab.... Problem is, I don't think she can take the meter from the lab. But MAYBE, bringing my wort to her lab on a weekend, and oxygenating there could be possible..... It's a BIG stretch though! I'll try to call in the favour. In the mean time, I'm saving my pennies for one myself.
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Weizenberg
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Re: How are most people here measuring their fermetation temperature?

Postby Weizenberg » Sun Oct 16, 2016 7:58 am

Nick_D wrote:
Brandon wrote:Nick_D, what controller are you using? Ancient, it looks like you're using a Ranco. which is what I used to use. The BrewPi vs Ranco might provide the same level of accuracy, but the BrewPi does great graphing of multiple data points (freezer, fermenter, +1 - room, heater, whatever) along the way. I feel like that gives a more rounded picture and you can 'see' the heat generated by fermentation by the BrewPi adjusting heating or cooling to compensate. Something to consider as I find it to be an order of magnitude better resolution of information.

As an aside, I did a Zero wort aeration fermentation with yeast that was at high krausen and it knocked it down fine. So aeration may not be as much of a factor.


Hmmm, well I don't have an automated setup like most here, Brewpi's and such. Just an STC-1000 with 0.1 C temperature resolution. I'm plagued with having to make all my inputs manually. So I'm johnny on the spot. I set alarms to tell me to adjust 0.2 up or down depending on what phase of fermenting I'm supposed to be in.


I've got a STC-1000 (2 outputs, heat and chill) and it does the job nicely. No need for Brewpi imo. I modify the setpoints manually every morning and every evening. Been doing that for 5 years and I see no reason to change that.
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