Infections in sour beer

[Rob2010SS]

I do not have an infection, this is more of a curiosity thing at the moment.

In a beer that is 3.3 pH and at an ABV of 5.25%, what kind of infection COULD you get from adding fruit? Is there anything that could live on the fruit and take hold in that environment?

I've never soaked fruit in water with camden tablets, as some people recommend. I've always just had good luck with freezing the fruit first. What got me thinking about it is the fact that this beer is one that I've posted about recently on HBT and how it stalled on me at 1.041 with expected FG of 1.027. After adding the fruit, it actually woke it up and it is fermenting again.

The beer is split between 2 fermenters and one of them is clear so I can see it. There's nothing nasty growing on it and it looks to be pretty healthy, just fermenting again. But it just got me thinking is all.

So again, just curious, what kinds of things could get in that could infect the beer at the current pH and ABV levels? Is there all kinds of bacteria that could or is it pretty limited? Anyone gotten an infection in a sour beer from adding fruit?

 

[Vale71]

Basically anything that can infect a non-sour beer.

 

[Rob2010SS]

Basically anything that can infect a non-sour beer.

Ha, fair enough. I guess I was thinking that the alcohol prevent and the low pH would prevent some things.

 

[goodolarchie]

I do not have an infection, this is more of a curiosity thing at the moment.

In a beer that is 3.3 pH and at an ABV of 5.25%, what kind of infection COULD you get from adding fruit? Is there anything that could live on the fruit and take hold in that environment?

....

So again, just curious, what kinds of things could get in that could infect the beer at the current pH and ABV levels? Is there all kinds of bacteria that could or is it pretty limited? Anyone gotten an infection in a sour beer from adding fruit?

Fruit is a really common source for (purposefully) harvested yeast and bacteria, there would be no way of knowing exactly what could have inoculated the beer from this fruit without a much, much, much closer look. At 3.3pH and 5% abv I wouldn't worry too much, but depending on your IBUs you could have further souring from LAB happening under the hood. Just keep monitoring it and know if it's brettanomyces, the beer will probably end up better!

 

[Vale71]

An ABV of 5.25% is nothing exceptional and beer spoliage organisms have to be able to thrive in an acidic environment so in that regard you are helping rather than hindering them.

 

[Rob2010SS]

Fruit is a really common source for (purposefully) harvested yeast and bacteria, there would be no way of knowing exactly what could have inoculated the beer from this fruit without a much, much, much closer look. At 3.3pH and 5% abv I wouldn't worry too much, but depending on your IBUs you could have further souring from LAB happening under the hood. Just keep monitoring it and know if it's brettanomyces, the beer will probably end up better!

Ha, don't know about that. Not a huge fan of brett. Thanks for the info.

 

[Rob2010SS]

An ABV of 5.25% is nothing exceptional and beer spoliage organisms have to be able to thrive in an acidic environment so in that regard you are helping rather than hindering them.

Interesting. Never thought of it that way. I always thought that the lower the pH, the harder it was for anything to take hold. But I do see your point.