Does Pediococcus survive

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Calder

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I've been trying to learn as much as I can about wild beers. I keep coming across notes that say Pedio dies in the presence of oxygen. What does this mean?

If you pitch a mix of bugs to begin with and aerate the wort, how does the pedio survive?

If you create an environment where some small amount of oxygen can enter the beer (say a wooden barrel, or an HDPE fermenter), does this kill the pedio.

I'm having difficulty understanding how pedio can work, or survive, in any sours when every reference I read (even 'Wild Brews') says it cannot survive in oxygen.

Every beer we make we aerate the crap out of it at the start, and if we are pitching a mixed of bugs, the pedio should be severely disabled.
 

ryane

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Ive seen that thrown around a lot as well, but to be honest Ive not seen any literature that says that the pedio used in brewing is actually an obligate anaerobe. Im not even sure what the strain of pedio that WY/WL offer is, they dont give any additional information other than Pediococcus. It even could very well be that the pedio we use is an obligate anaerobe and its not damaged by oxygen, however it most likely is to some degree.

1 - there are always some stronger cells that resist negative effects. the thing that comes to mind is the predator-prey charts that you sometimes see. No matter how many predators there are some prey always survive. Depending on how tolerant the pedio truly is and how much you aerate its possible you could kill all of them but Id bet its not that likely

2 - I would doubt it, there are different zones in a barrel. Nearer the wood surface there may very well be dissolve oxygen, however it is rapidly used up by bacteria/yeast and near the center of the barrel it is most likely completely anaerobic.

3 - mind sharing these references? My guess is that it is hampered to some degree by oxygen, but at the levels we generally supply to it whether through aerated starters etc that at least a few cells manage to survive and repopulate the beer

Usually when brewing a sour I do not aerate, in fact Ive gone so far as to sparge a beer with helium to completely remove dissolved oxygen before adding brett/bacteria before. In your beers with significant oxygenation, the pedio may be hampered/killed but the oxygen wont last in the system very long. The few cells that do make it through will be able to grow and sour your beer, it just might take a bit longer to get going

I think this could be a good question for Al over on BBB. Somehow I bet he would have a lot more information available to be able to fill in the gaps in detail/understanding
 

davefleck

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I don't think it dies with O2 but just lies dormant waiting for a favorable environment to reproduce.
 
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pediococcus and lactobacillus both are gram negative bacteria that are classified as microaerophiles, or faculative anerobes. That means they can use oxygen but atmospheric levels are almost toxic to them, lower levels are what they like in the almost anerobic environment or beer.
 

ryane

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pediococcus and lactobacillus both are gram negative bacteria that are classified as microaerophiles, or faculative anerobes. That means they can use oxygen but atmospheric levels are almost toxic to them, lower levels are what they like in the almost anerobic environment or beer.
Do you have any references? Especially about what actually is offered by WL/WY?

Pedio Pentosaceus is actually gram positive
http://microbewiki.kenyon.edu/index.php/Pediococcus_pentosaceus
 
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I should have specified most lacto and pedio involved in brewing are gram negative. P. cerevisiae is gram negative as is L. delbrueckii. I know there are other organisms but the offerings from WL/WY I think are the the ones I mentioned.
 
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I must have been drinking when I posted these two messages or just straight stupid that day. The lacto and pedio are gram positive. Anyhow...I'm going to grab another beer. hahaha
 
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I thought the, "pedio dies in oxygen" statement came out of Wild Brews. I could be wrong. I know I have seen it frequently repeated.

Pediococcus cannot have zero tolerance for oxygen, otherwise it would be virtually impossible for pedio to spread in nature. I assume the more accurate statement is that pedio can die with too much oxygen exposure (such as an over-oxygenated environment) but remains dormant under normal conditions until the oxygen decreases to a satisfactory amount.
 
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