Tuesday, 9 September 2014

If at first you don't succeed, throw everything out and try again!

Its been another bad day - beginning a few months ago with my first dumper in 7 years, due, I thought, to mis-management of the Brett used in that beer. This was followed by an apparently successful cranberry wit, and then my all-Brett Russian Imperial Stout. The stout started off well, but has since taken a turn for the worse - the same chemical/lemon aroma that appeared in my dumper also began to emerge from this beer, along with a horrid solvent/chemical flavour. At the same time the apparently successful wit began to develop a viscous mouth feel and some odd aromas. Despite all of this, the parti-gyled beer pulled off of the second runnings of the stout fermented fine and has turned into a surprisingly good beer. So what went wrong?

I took a sample of the RIS to work and inspected it under a microscope. I forgot to snap an image, but mixed in among the cute "mickey mouse" Bretts were filamentous rod-shaped bacteria - a lot of them. I am unsure of the exact species that the bacteria may be, but regardless, they are unwelcome guests.

The one common link between the contaminated beers, but lacking from the parti-gyle, was the use of the same plastic fermenter. This, despite repeated rounds of cleaning and sanitation is most likely the source of the contamination, meaning I am now the proud new owners of a large plastic bucket with no apparent use...and after a short trip to the LHBS, the owner of a brand-new bucket and siphon for brewing (I chucked the old siphon to be safe).

I hope this solves the issue - but in two weeks when I re-brew the Russian Imperil Stout, I'll be primarying it in glass...the new bucket is going to be broken in this weekend on a wet-hop ale!

5 comments:

  1. I just found your blog and I am enjoying reading it.
    I did some fermentation experiments on fermentors a few years ago. Stainless, conical, glass, bucket, better bottle, etc.
    I will ferment wild beers in better bottles, sacc. beers in glass or stainless, and nothing in plastic buckets as a result.

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    1. I often ferment in glass carboys, but I still prefer the relatively "open" fermentation of the bucket system for estery beers. The extra contact with air aids in ester formation, and IMO, produces nicer flavour profiles than does a more closed carboy-like fermenter.

      Of course, being plastic, the buckets come with their own concerns.

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  2. I am lucky enough to not have had a contaminated batch yet, but I keep hearing more and more stories like this, and am in the process of transitioning to glass fermentors as I retire the buckets. The lack of oxygen issue is definitely something that concerns me, but I think I will slowly figure that out with ported or porous stoppers or something. Sorry to hear about your throw-aways though, I can commiserate with that. Absolutely miserable feeling!
    - Dennis, Life Fermented Blog

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    1. I've read of people plugging the hole in a bung with sterile cotton as a stop-gap measure for the oxygen access issue with carboys. The only problem I see with that is that you are now relying on temperature fluctuations to pull air in/out of the carboy as diffusion is going to be minimal through such a small opening. I'm "burdened" with a very temp-stable basement, so I'm not sure that would work for me.

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    2. I'm actually not all that concerned with the O2 for short-term ferments, more worried about my long-aging sours.

      But you might be able to use cotton and filtered air fed from an aquarium pump for a standard brew. The tube end could be left above the wort in the airspace, and the CO2 and extra air would go out through the cotton. Or maybe same system, but with an airlocked stopper drilled with an extra hole for the pump feed air tube. Smacks of overkill, but whats homebrewing without overkill solutions?
      - Dennis, Life Fermented Blog

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