Contamination on First-Time Fruit Beer?

Discussion in 'Beginners Brewing Forum' started by Mitchthebrewer, Mar 18, 2019.

  1. Mitchthebrewer

    Mitchthebrewer New Member

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    So I wanted to try a fruit beer, and recently got to doing one with Passionfruit. It's in a secondary at the moment with the fruit. It is only a small 5 L test batch :)

    I went away over the weekend and came back to the brew with a film of white material on top. There are no discernible off smells, and I risked a small taste and there is no indication of off flavors. Everything smells and tastes fine, but there's this white material. It almost looks like the film that milk gets if you put in in the microwave to heat it up, or leave it out too long. The white material does not seem to be anywhere except the very surface of the brew.

    Has this beer been contaminated? Or has some kind of film from the fruits just formed on top? I've never brewed a fruit beer before so I'm not too sure. (That slightly yellow stuff you see is the passionfruit).

    Cheers!



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  2. J A

    J A Well-Known Member

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    Oh, yeah! ...That's the start of a pellicle that'll produce a lot of lactobacillus and sour flavor in the beer eventually. Part of it could be just simple food mold, too. Most likely the fruit brought in some micro-organisms into the mix and/or opening the bucket a few times has allowed environment agents to intrude.
     
  3. Mitchthebrewer

    Mitchthebrewer New Member

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    Any point in trying to bottle it? Siphoning below the material perhaps?
     
  4. Nosybear

    Nosybear Well-Known Member

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    May work, depending on the contamination.
     
  5. J A

    J A Well-Known Member

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    Since it's a small batch, you could try to sneak it into bottles and carefully monitor how it carbs up. Be aware that the contaminating organism will keep consuming sugars and the typical calculations for priming don't necessarily apply. If you chill it as soon as a reasonable carb level is achieved and keep it chilled, you might have a few bottles of beer to try. Most likely the off flavors will assert themselves in the bottle.
    Only other hope is to let it finish out as a sour. Typically, they'll go quite low in gravity over a couple of months, sometimes less, and get stable enough to carb up without exploding. After that, it's all about mellowing out so that the flavors are pleasant.
    Others may have some ideas but brewing and bottling sours and lambics can be an art form unto itself. :)
    PS...That bucket will probably be useless now that it's got some funkiness going on. Keeping it and trying to sanitize it enough is not really worth the risk to lose future batches.
     
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  6. AHarper

    AHarper Well-Known Member

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    I had that on a cider batch once... didn't notice it until after bottling. Ditched the lot after testing a few.
     
  7. Mark Farrall

    Mark Farrall Well-Known Member

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    The thin film is the pellicle and you've got bits of mould on top of that as well. The mould is the one to worry about.

    Any idea of the pH and ABV when you added the passionfruit? It's difficult to grow nasties in beer over about 3% ABV and pH closer to 4. The main reason everyone drank beer prior to clean water.

    A pellicle forming seems to be brett and/or other microbes creating a film in reaction to the amount of oxygen they get. It doesn't really tell you a lot about whether the beers going to be good or not. I've brewed batches that have been awesome with a pellicle and other that are also great without one. And a few that were rubbish the other way.

    I wouldn't try bottling until you've sampled some. There's not a lot of moulds that will give you a flavour you'll want to drink. Make sure it's very small samples and if the ABV is under 3% and the ph is closer to 5 I probably wouldn't even sample it.
     
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  8. Hawkbox

    Hawkbox Well-Known Member

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    I kegged a carboy that had growth on the top very carefully with a siphon and it came out fine, so you could try it. It's a roll of the dice though.
     

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