Cross-contamination

Discussion in 'General Beer Brewing Discussion' started by Hoppyland, Oct 12, 2018 at 10:25 PM.

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  1. Oct 12, 2018 at 10:25 PM #1

    Hoppyland

    Hoppyland

    Hoppyland

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    I've recently branched out into fermenting things that aren't beer.
    I reckon that, for the last 25 years or more I haven't had a single batch of beer that was ruined by spoilage organisms of any sort. I put this down to 3 things: Decent hygiene, purging every deadspace from a large CO2 cylinder, and possibly living in a remote area in Scotland - I hardly see fruit flies etc (although I am paranoid when I do!). Luck must also be a player, but after this length of time not a huge one, I feel.
    What I'm worried about is: could this all be about to change??
    For some reason, I've just become interested in a variety of other fermentation processes. I've made my own bread for some time, to date using baker's yeast, but I've now got 3 sourdough starters on the go. These contain both yeasts and bacteria - and ones that are happy to ferment carbohydrates at room temperature in anoxic conditions - so if they will grow in, and therefore contaminate/spoil beer, my CO2 purging will be entirely futile.
    Worse, perhaps, I'm also having a go at more esoteric stuff. At the moment, a type of yoghurt that works at room temperature, and also a thing called "ginger kefir water". This is apparently another yeast/bacterium symbiosis that ferments sugars happily at room temperature in the absence of oxygen.
    So, it seems to me, that the probability of some of these "wild" yeasts and bacteria getting into my beer are quite high unless I step up my procedures to virtually genuine sterilisation, which is clearly not practical.
    My question, therefore, is this. Has anyone had problems with their beer which they put down to cross-contamination from other fermentation processes?
    I'd appreciate the benefit of any experiences, positive or negative. I might also try inoculating a few bottles of beer ( when I produce an indifferent brew!) with a few of these things, just to see if they take hold.

    Oops!! Just realised - I thought I was posting this under "General Beer Brewing Discussion.. " and not "General Beer Discussion". Ah, well - shows it's time for bed!
     
    Last edited: Oct 12, 2018 at 10:31 PM
  2. Oct 13, 2018 at 1:06 AM #2

    Dutto

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    How do you expect a contamination to occur?

    Apparently there are zillions of wild yeasts floating about in the air already so adding few more shouldn't make much difference.

    When I had kids, I brewed beer and made yoghurt in the same airing cupboard without any problems that I remember and I've also made bread using the yeast from the trub in a brew without making the bread taste horrible.

    Surely, your sourdough starters are in sealed plastic containers and liquids are secured in FV's with air-locks? Air-locks and Blow-Off Tubes work in both directions which is why I use a water/bleach mixture in them.

    About the only way I can see a significant cross contamination occurring is if you are using the same equipment for making the various yeast derived products; and even then a relatively easy sanitisation regime should be sufficient to prevent it.

    Look on the bright side. IF a cross contamination occurs, it will probably be all your own fault and not the fault of some poor innocent fruit fly!
     
  3. Oct 13, 2018 at 7:18 AM #3

    Cwrw666

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    Be careful you might end up being responsible for a new craft beer trend - yoghurt beer. Or sourdough beer. Can't be worse than that bottle of vomit beer I had from Tescos a while back, Bakewell Tart or somesuch.
     
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  4. Oct 13, 2018 at 10:47 AM #4

    Hoppyland

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    Well, my sourdough starters aren't in sealed containers - they're in Kilner jars with the rubber seal removed, to let CO2 escape. It seems that bread makers (or, indeed, yoghurt or kefir water makers) aren't nearly as concerned about sanitisation as brewers. Apparently, with sourdough starters, provided you keep the culture supplied regularly with fresh flour then the yeast/bacteria mix maintains its own environment (largely through reduced pH). Over time, a particular mix of micro-organisms will develop and stabilise to suit the particular flour you're using, and the environmental conditions. It's reckoned that some cultures have been going uninterrupted for over 100 years.
    However, the most likely area where'd I'd expect problems is in the kitchen, where I both bake and brew. Starters and doughs tend to be messy, sticky things, with a propensity to get everywhere! Difficult to get off my hands thoroughly, as well, so loads of opportunity to contaminate the kitchen towel. In the case of the ginger kefir water, it ferments by the activities of a combination of Saccharomyces, Brettanomyces, and 4 different lactic bacteria. I'm assuming that, by making this, I'm deliberately building up numbers of these way beyond levels that would normally be found in my house, hence the worry.
    As you say, though, basically its down to me to achieve "biological security" - but I was wondering if anyone had experience of this situation, and whether my concerns were more theoretical than an actual practical problem.
    But, anyway, what is this innocent fruit fly of which you speak? There are no innocent fruit flies. I hate 'em all - even though I don't see many! And, yes, my wife does think I'm paranoid when I chase one round the kitchen with a hand sprayer of soapy water......... although she's grown accustomed to a variety of strange behaviours over the years asad1
     
  5. Oct 13, 2018 at 11:01 AM #5

    Hoppyland

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    Well I had to look that one up!!
    Oddly enough, Thornbridge Brewery don't go into detail about the vomit bit. Instead, they claim their Bakewell sour beer "is refreshingly tart and dry with a combination of citrusy hops and flavours of grapefruit and bitter lemon." I take it that you wouldn't agree!
    I must say that you haven't tempted me to try it - but then I didn't like the Belgian sour beer I did try. Which I guess is why I was worried about large quantities of lactic bacteria getting too near my brews!
     
  6. Oct 13, 2018 at 11:55 PM #6

    Dutto

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    If I stick my hands and/or arms into anything to do with brewing I spray them with StarSan solution after washing with Wrights Coal Tar soap and cleaning under my fingernails.

    Luckily, I'm not allergic to anything so I haven't got galloping dermatitis or anything similar; but as a retired HSE Manager I guess I should be wearing the kind of gloves that vets use when they explore the nether regions of a cow!
     
  7. Oct 14, 2018 at 1:47 PM #7

    MarkBowie

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    Unless you actually contaminate it you will be fine. The yeast in sourdough is in the air and on the wheat hull, that’s why stoneground, organic flour is always recommended (rye flour is always more consistent for the starter). So because of that, if your cleaning/sanitation routine worked before then it’ll work just fine now.
     
  8. Oct 14, 2018 at 1:50 PM #8

    foxbat

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    It's your secret ingredient: the fearsome highland midge! :laugh8:
     
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