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General Category => Yeast and Fermentation => Topic started by: klickitat jim on February 13, 2014, 12:38:32 am

Title: Ambient vs Actual (sort of)
Post by: klickitat jim on February 13, 2014, 12:38:32 am
I've been running my freezer temp probe just off the ambient air temp. Tonight I'm brewing three beers that will all go at the same temp. So as a trial run to see if it makes enough difference, I'm attaching the probe to the first batch under some insulation. Initially it read 52° but over an hour its at 54°. What I'm hoping for is stability as the yeast goes through high krausen and starts to drop. After everyone has dropped I may ramp it a degree or two per day up to 60-62° until finished. I'll report back with results.
(http://img.tapatalk.com/d/14/02/13/u8e4a6y5.jpg)
Title: Re: Ambient vs Actual (sort of)
Post by: Jimmy K on February 13, 2014, 07:21:15 am
Looks good. Just keep an eye on them since you have three going. If the one with the probe were really active and warm, the freezer might cool the others too much.
Title: Re: Ambient vs Actual (sort of)
Post by: pinnah on February 13, 2014, 07:30:24 am
Three! Nice work! 

I just wanted to ask what kind of fermenting vessel you have there? 
Title: Re: Ambient vs Actual (sort of)
Post by: duboman on February 13, 2014, 08:52:11 am
The first time I ran my probe for ambient I found a lot of fluctuation in the the readings and things were usually running a little too cold. I started strapping the probe against the primary with some wadded up insulation to protect it and found temps became much more exact with where I wanted them to be regardless of how many vessels I have in there. I have the stick on strips on all my vessels and they would all read +/- 1 degree within the probed vessel even at varying stages of fermentation.
Title: Re: Ambient vs Actual (sort of)
Post by: klickitat jim on February 13, 2014, 04:28:33 pm
Three! Nice work! 

I just wanted to ask what kind of fermenting vessel you have there?

Cambro 6 gallon polycarbonate
Title: Re: Ambient vs Actual (sort of)
Post by: klickitat jim on February 13, 2014, 04:32:37 pm
Looks good. Just keep an eye on them since you have three going. If the one with the probe were really active and warm, the freezer might cool the others too much.

Three beers, ranging 1.050-040. I decided to put it on first batch because it was the biggest. So far it's the first to high krausen, the other two not far behind. They were all pitched a few degrees below target. So in theory this should work. Looks like they are all following about 12 hr lag times.
Title: Re: Ambient vs Actual (sort of)
Post by: Stevie on February 13, 2014, 04:40:50 pm
You still liking those polycarbonate cambros Jim? Easy enough to lift when full?
Title: Re: Ambient vs Actual (sort of)
Post by: klickitat jim on February 13, 2014, 05:21:13 pm
Oh ya. They are great.
Title: Re: Ambient vs Actual (sort of)
Post by: klickitat jim on February 13, 2014, 08:04:58 pm
14 hrs since I pitched the last of the three and they're all at high krausen. Temp reading 55° and it doesn't seem to be cycling near as much as the ambient method. So far so good. I just have to remember to step it up when krausen starts to fall.
(http://img.tapatalk.com/d/14/02/14/sa2a8u7y.jpg)
Title: Re: Ambient vs Actual (sort of)
Post by: klickitat jim on February 15, 2014, 09:35:26 pm
All three at high krausen for 36~ hours so far. I've stepped it up from 55 to 57. Looking good so far.
Title: Re: Ambient vs Actual (sort of)
Post by: dzlater on February 16, 2014, 05:51:13 am
I'm curious, do you know the difference between the ambient air temp and the wort temp?
I always read that the fermenting beer can be 10 degrees warmer, I'm a bit skeptical of that with a five gallon batch.
Title: Re: Ambient vs Actual (sort of)
Post by: klickitat jim on February 16, 2014, 06:11:27 am
I don't. But it would swing wildly depending on if the heat was on or the cool. Maybe someone who doesn't use temp control could test that out and post the results.

I ferment fairly cool, not terribly worried about my beer getting too hot during high krausen, but I don't want it to drop in temp as the krausen begins to fall.
Title: Re: Ambient vs Actual (sort of)
Post by: morticaixavier on February 16, 2014, 07:17:43 am
I'm curious, do you know the difference between the ambient air temp and the wort temp?
I always read that the fermenting beer can be 10 degrees warmer, I'm a bit skeptical of that with a five gallon batch.

I'm pretty sure the experiment has been done. Temp sensor in a thermo well inside the fermenter and another in the surrounding air. 10 degrees is a little extreme except for in the biggest of beers but 5-7 is not out of the question.
Title: Re: Ambient vs Actual (sort of)
Post by: erockrph on February 16, 2014, 09:08:12 am
I'm curious, do you know the difference between the ambient air temp and the wort temp?
I always read that the fermenting beer can be 10 degrees warmer, I'm a bit skeptical of that with a five gallon batch.

I'm pretty sure the experiment has been done. Temp sensor in a thermo well inside the fermenter and another in the surrounding air. 10 degrees is a little extreme except for in the biggest of beers but 5-7 is not out of the question.

+1 - Even with just a fermometer I've seen up to 7 degree increases over ambient in a 3-gallon batch of a high-gravity brew.
Title: Re: Ambient vs Actual (sort of)
Post by: euge on February 16, 2014, 09:10:50 am
And I get little to no difference in a freezer that has a small fan moving the air around.
Title: Re: Ambient vs Actual (sort of)
Post by: a10t2 on February 16, 2014, 10:40:35 am
You have to make a lot of assumptions, but if you have 5.5 gal of ~5% ABV beer and it ferments out over 72 hours, with only conductive heat transfer to the surrounding air for cooling, the average temperature differential works out to ~4°F. Obviously fermentation isn't steady-state in the real world; at high krausen 2.5 times the average wouldn't surprise me at all.
Title: Re: Ambient vs Actual (sort of)
Post by: klickitat jim on February 17, 2014, 06:23:08 pm
So lag time was less than 12 hrs, had full krausen by 18 hrs. That was last Wednesday evening. Krausen just now fallen. Seems like it stayed in Attenuation phase markedly longer than normal. I started ramping the temp up one degree every 12 hrs starting Friday night when it looked like krausen was starting to subside. Starting temp was 55°. I have it set for 62° now and the beer is at 59° with the heat working it up.

It's too early to comment on overall quality but, five full days of active krausen attenuation is about double of what I normally see, and the only change was temp probe placement and slow ramp up when activity looked like it was past peak.

I'm sold!
Title: Re: Ambient vs Actual (sort of)
Post by: klickitat jim on February 21, 2014, 02:57:43 am
At one week I checked gravity. Oktoberfest OG 1.050 now 1.018, 80/- OG 1.040 now 1.017, Vienna OG 1.050 now 1.019. Looking good tasting good. I've got the temp at 70° now. I think I'll give them another week and recheck.