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General Category => Yeast and Fermentation => Topic started by: TeeDubb on January 07, 2018, 07:01:03 PM

Title: Defect Diagnosis
Post by: TeeDubb on January 07, 2018, 07:01:03 PM
I recently brewed a gluten free Pale Ale using the Ground Breaker Brewing recipe (with different hops) that was posted a few months ago. I racked to keg last night and something was clearly off.


I normally brew all grain, so a partial mash brew seemed fun with the intent to make a GF ale for a few gluten sensitive friends that don't drink beer. Brew day went without issue. I started with RO water, added a little gypsum and calcium chloride to suit the style. Wort pH was 5.35 before the boil. The wort tasted fine going into the fermenter. I used US-05 which became active about 12 hours after pitching.  I kept fermentation at 66-67 for 5-6 days and ramped up to 68-69 after activity seemed to subside. OG was 1.052 and FG was 1.009 after 11 days.  Fermentation seemed slower that usual, but steady.

After racking to keg and adding dry hops, I evaluated a sample from the fermenter. Appearance was as expected (light gold / orange).  Aroma was earthy with some rubber in there!  Maybe a touch of phenolic.  I did not get band aids directly, but maybe there is some of that in there too.  Flavor matches the aroma if that makes any sense. I also noticed that there was a thick layer of very loosely flocculated yeast at the bottom of the fermenter. I think I lost at least .75 gal during racking to keg. I have never seen that with US-05 or from the 4-5 other liquid strains I typically use. Photos at link below - note that I did seem to transfer some hop matter from the boil kettle because my revised whirlpool method did not work as planned to collect trub in the middle.


My question is if anyone has experienced this type of defect and/or the yeast flocculation behavior.  I suspect that I got an infection somewhere, despite my usual liberal use of Star-San and extensive equipment cleaning. Maybe my RO water source gave me some chlorine? I'm trying not to blame the GF ingredients :) but the next batch is likely go back to my usual recipes.  I'm going to let this one sit in the keg for 1-2 weeks and then likely dump it, but it would be nice to understand what may have happened.
Title: Re: Defect Diagnosis
Post by: Frankenbrew on January 07, 2018, 09:40:53 PM
Were your ferment temps ambient or actual fermenter temp?
Title: Re: Defect Diagnosis
Post by: TeeDubb on January 07, 2018, 10:31:30 PM
They are thermowell temps inside the wort.  I use an external chiller and cooling coil inside the fermenter.
Title: Re: Defect Diagnosis
Post by: dannyjed on January 08, 2018, 01:35:11 AM
It could be wild yeast contamination. I had some yeast over a year ago that I had stored from a previous batch that ruined two batches before I figured it out. They both had a rubber, phenolic taste that was unpleasant. I had to dump both batches. You might want to switch sanitizers to idophor which works better against wild yeast.

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Title: Re: Defect Diagnosis
Post by: TeeDubb on January 09, 2018, 01:27:45 AM
Thanks!  Maybe it's time to replace o-rings and gaskets in the fermenter.  I will get some idophor and give that a try too before the next round.