Tainted batches - what is wrong? - Page 4 - Home Brew Forums

Register Now!
Home Brew Forums > Home Brewing Beer > Fermentation & Yeast > Tainted batches - what is wrong?

Reply
 
Thread Tools
Old 06-25-2013, 09:54 PM   #31
Brewsit
Recipes 
 
May 2011
San Antonio, TX
Posts: 203
Liked 20 Times on 18 Posts


You guys might be right about the temp calibration. I am using a stainless thermowell with the probe at the bottom of it. I will calibrate the temp controller and get back with the results of that.

 
Reply With Quote
Old 06-25-2013, 09:56 PM   #32
BigFloyd
Recipes 
 
Dec 2012
Tyler, Texas
Posts: 5,268
Liked 759 Times on 652 Posts


Where do you measure the temps you mentioned? On the fermenter? Ambient air?

What yeast(s) did you use on the batches that had the bad flavors? Some yeasts (like Nottingham and sometimes S-04) get nasty above 68*F (measured on the bucket).
__________________
Good Temp Control -----> Happy Yeast ------> Tasty Brew

 
Reply With Quote
Old 06-27-2013, 09:37 PM   #33
Brewsit
Recipes 
 
May 2011
San Antonio, TX
Posts: 203
Liked 20 Times on 18 Posts


Update:

So, I went out to take a quick temperature comparison with the thermometer that I THOUGHT was calibrated... I calibrated it with boiling water and it was good. However, at the lower end, I think it might be off. In a cup of warm water, it read 95F when the temp probe read 90. At first I thought, "yes, there is my problem". However, I checked it against a digital meat thermometer AND a digital medical thermometer, and both read the same as the temp probe. So, if three out of four thermometers read similarly, I am lead to believe that my analog thermometer is off by 5 degrees. Let me know if this seems like it's too far a stretch.

 
Reply With Quote
Old 06-27-2013, 10:02 PM   #34
Hopper5000
Recipes 
 
Oct 2011
Oakland, CA
Posts: 1,256
Liked 88 Times on 67 Posts


put them all in boiling water and see if they read 212 too. seems like you might be right though...

 
Reply With Quote
Old 06-27-2013, 10:09 PM   #35
duboman
Recipes 
 
Jul 2011
Glenview, IL
Posts: 6,368
Liked 508 Times on 470 Posts


Sounds like the issue but also check it in ice water at the low end as well. 5 degrees is a pretty big discrepancy.
__________________
Nothing Left to do but smile and drink beer.....

The Commune Brewing Company-Perfecting the "art" of beer since 2010

 
Reply With Quote
Old 06-27-2013, 10:28 PM   #36
Brewsit
Recipes 
 
May 2011
San Antonio, TX
Posts: 203
Liked 20 Times on 18 Posts


Checked against boiling water, and they all read the same, so on the high end everything looks good. Checked against ice water, everything reads the same as well, and accurate. For whatever reason, the analog thermometer is way off between 70 and 100 or so. Checked the digital meat thermometer against the probe and they are less than a degree from each other.

I was thinking about something, let me know if this sounds off... with the mass of the fermenter, and the probe being about halfway down and halfway in (half the distance from the center and outside wall), is it possible that the fermenting wort is warming enough on the outside of the fermenter and allowing the conditions for too high of fermentation temperatures? The A/C unit only kicks on when the probe gets to the right temperature, but the ambient air is warmer than the mass of the container usually, until the a/c runs. The entire thing is insulated, and stays rather cool, so I don't know.

On the next batch I am going to aim for the very lowest temp that the yeast will tolerate and see what happens...

 
Reply With Quote
Old 06-27-2013, 10:59 PM   #37
duboman
Recipes 
 
Jul 2011
Glenview, IL
Posts: 6,368
Liked 508 Times on 470 Posts


Analog thermometers can take a bit to adjust IME.

I doubt the wort would have that large a temp swing from one location to another in the vessel, it's not going to swing that quickly as its a pretty good insulator by itself, think swamp cooler and the insulation that provides.

I would try the lower end next time as well and see how it goes.
__________________
Nothing Left to do but smile and drink beer.....

The Commune Brewing Company-Perfecting the "art" of beer since 2010

 
Reply With Quote
Old 12-13-2013, 12:10 AM   #38
Brewsit
Recipes 
 
May 2011
San Antonio, TX
Posts: 203
Liked 20 Times on 18 Posts


I owe a follow up to this thread. Since the last update, I have dropped the fermentation chamber temp to 65 and have had zero issues. The saison mellowed out and was actually a favorite of mine and of everyone who drank it. The best bitter that I made has mellowed out a lot, but there is still a hint of off flavor that makes it not the greatest thing to drink, especially with other great beers available. I think temperature was definitely the issue.

 
Reply With Quote
Old 12-14-2013, 01:26 AM   #39
jbaysurfer
Former future HOF Brewer
HBT_LIFETIMESUPPORTER.png
Recipes 
 
Nov 2011
Santa Barbara, CA
Posts: 2,937
Liked 590 Times on 429 Posts


It's nice to see a "what's wrong" thread that ends with some resolution. Congrats. That was my most frequent early error...ferm temps. Now I learn what my yeast likes and it gives me what I like....delicious beer!
__________________
Batch counter: 123 batches (11/29/11-7/22/15).

 
Reply With Quote
Old 12-14-2013, 03:02 AM   #40
EarlyAmateurZymurgist
Recipes 
 
Aug 2013
Posts: 480
Liked 120 Times on 74 Posts


Banana is an ester called isoamyl acetate. It is formed when isoamyl alcohol combines with acetic acid. While high fermentation temperatures can cause yeast to produce isoamyl acetate, poor health and under-aeration also lead the formation of the ester. With most yeast cultures, isoamyl acetate production is mother nature's way of telling us that the culture experienced stress during fermentation.

Anyway, it is nice to see that there was a happy ending to your problem. I am not that patient. I dislike the taste of isoamyl acetate so much that I do not hesitate to dump batches that show as much as a hint of that ester.

 
Reply With Quote


Reply
Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
HELP! First 2 batches are bad, what am I doing wrong? AxDxMx Beginners Beer Brewing Forum 15 11-27-2011 06:10 AM
What to do with my tainted yeast JonBoy47 General Beer Discussion 12 08-10-2011 01:18 AM
Anything wrong with 1-gal batches? +advice on first brew cinderbike Beginners Beer Brewing Forum 9 10-27-2010 12:58 PM
Priming Beer - some questions after a few batches went wrong PuppetmanInBC Beginners Beer Brewing Forum 11 09-03-2010 10:39 PM
What went wrong with my strawberry batches? patrick767 Mead Forum 11 06-05-2010 03:17 AM


Forum Jump