Does Brettanomyces Need O2 in Secondary?

[dantheman13]

So there are a lot of references out there about how Brettanomyces can metabolize micro-oxygenation. But how much is too little? I'm not talking about 100% Brett fermentations or fermentations that rely on Brett to do the primary fermentation, but secondary fermentations of Brett that are geared towards producing those funky and fruity esters/phenols that we are after (or other beneficial processes from Brett that require O2).

I've often read that Brett produces a lot more "funk" when under pressure in the bottle or a keg. Is there any solid information out there, scientific or anecdotal, that shows that no or too little exposure to oxygen produces undesirable results from any Brett species/sub-species in a typical sour beer? In other words, is oxygen really needed in order to produce desirable results from any Brett sp in an aging environment?

Here is an answer that I received from a friend on Milk The Funk: "I think (not know) that oxygen does not catalyze ester/phenol production. Oxygen does, however, help Brett grow healthy and plentiful. If it's anything like cerevisiae (and who the hell knows) oxygen would reduce ester/phenol production since citric acid cycle is bypassed. Of course you need good enough conditions to breed enough brett to do the esterase business. I do not have an idea of how much (if any) oxygen is needed for brett to do their business. Good questions."

And a counter from another friend on MTF: "I would think that the opposite is true, actually. The less oxygen, the more Brett character. This would explain the more muted character in 100% Brett fermentations as opposed to secondary fermentation with Brett. Besides, the more oxygen that Brett is exposed to, the greater chance that you have of acetic acid production."

Thoughts?

 

[billl]

I don't know if there is some minimum threshold, but opening up the fermenter to drop the yeast in will be plenty of O2 for Brett to do its thing. You definitely don't need to worry about adding extra O2.

 

[dcp27]

as there is a number of funky brett beers where its only added at bottling (orval for instance), id say oxygen isnt needed

 

[dantheman13]

as there is a number of funky brett beers where its only added at bottling (orval for instance), id say oxygen isnt needed

Bottles are susceptible to micro-oxygenation.

 

[TAK]

Bottles are susceptible to micro-oxygenation.

This is an interesting point. From what I understand, bottle caps do leak, even with wax. Kegs, on the other hand, with scrupulous attention to detail, I think can be void of O2. I'm aging my first (intentionally) Brett'ed beer in a keg now. However, I did not go to the scrupulous efforts to keep all O2 out, since I knew Brett would scavenge it. I wonder, though, how well Brett would do in a Keg without any O2-introduction points in the process. That said, I feel like I can completely purge a keg and closed transfer into it without introducing O2, but I'm not sure how you'd combine a culture of Brett with a batch of beer without, in that act itself, at least introducing a small amount of O2.

 

[dantheman13]

This is an interesting point. From what I understand, bottle caps do leak, even with wax. Kegs, on the other hand, with scrupulous attention to detail, I think can be void of O2. I'm aging my first (intentionally) Brett'ed beer in a keg now. However, I did not go to the scrupulous efforts to keep all O2 out, since I knew Brett would scavenge it. I wonder, though, how well Brett would do in a Keg without any O2-introduction points in the process. That said, I feel like I can completely purge a keg and closed transfer into it without introducing O2, but I'm not sure how you'd combine a culture of Brett with a batch of beer without, in that act itself, at least introducing a small amount of O2.

Agreed. My question is mostly theoretical, not practical. It does lead into another more practical subject though, which I am still working on researching (this was part of that research).