14 replies to this topic

[Jimmy James]

Been reading up on some stuff lately and am wondering how common of a practice this is amongst pro breweries to speed up or unstick fermentations?

[RommelMagic]

I've never added O2 after fermentation has started. Unless you want to speed up the aging (as in old, stale beer with cardboard or sherry off flavors) process I would avoid adding any O2 after fermentation started. Even firkins / cask ales only last a few days until they go bad.EDIT: BTW, I'm not a pro. post typed just IMHO

Edited by RommelMagic, 04 June 2010 - 01:53 PM.

[Jimmy James]

I've never added O2 after fermentation has started. Unless you want to speed up the aging (as in old, stale beer with cardboard or sherry off flavors) process I would avoid adding any O2 after fermentation started. Even firkins / cask ales only last a few days until they go bad.

I am well aware of the conventional wisdom here, but also have seen scientific studies that indicate otherwise, and have very strong suspicions that breweries are in fact doing this.

[Given2fly]

I am well aware of the conventional wisdom here, but also have seen scientific studies that indicate otherwise, and have very strong suspicions that breweries are in fact doing this.

I was wondering this myself. In the latest BYO, Jamil has an article on Belgian Tripels and when discussing levels of oxygen, he says and I quote:'If you find yourself getting stuck fermentations when brewing high gravity beers, you can add a second dose of oxygen between 12 to 18 hours after pitching' Was considering doing so on one of my next big beers to see if there is a difference in reaching terminal gravity. Would also like to know of others experiences?.

[Jimmy James]

I was wondering this myself. In the latest BYO, Jamil has an article on Belgian Tripels and when discussing levels of oxygen, he says and I quote:'If you find yourself getting stuck fermentations when brewing high gravity beers, you can add a second dose of oxygen between 12 to 18 hours after pitching' Was considering doing so on one of my next big beers to see if there is a difference in reaching terminal gravity. Would also like to know of others experiences?.

Interesting, hadn't seen the BYO article but it jives with what I've been seeing in scientific pubs. Did Jamil mention any context around the 12 to 18 hour window or was that arbitrary?

[Given2fly]

Interesting, hadn't seen the BYO article but it jives with what I've been seeing in scientific pubs. Did Jamil mention any context around the 12 to 18 hour window or was that arbitrary?

Not really, just goes on to say 'The second dose should be between 1/2 to 1/4 the normal amount of oxygen. This will give the yeast the viability to rebuild their cell membranes after having replicated. They will better tolerate the high alcohol environment ahead with this additional oxygen.'

[ChefLamont]

I was wondering this myself. In the latest BYO, Jamil has an article on Belgian Tripels and when discussing levels of oxygen, he says and I quote:'If you find yourself getting stuck fermentations when brewing high gravity beers, you can add a second dose of oxygen between 12 to 18 hours after pitching' Was considering doing so on one of my next big beers to see if there is a difference in reaching terminal gravity. Would also like to know of others experiences?.

My guess is that for a big beer like that, most homebrewers under pitch by a little to a lot. If you are underpitched, the yeast are still in their growth phase and taking up the O2 like crazy. Therefore adding O2 will improve the growth, improving the cell count, and, hopefully, getting the fermentation more complete. Plus the alcohol production has not really started so you dont have as much risk of the negative oxidative reactions the you would fear later on into the fermentation or after for that matter.

[tag]

This was discussed with some of the Lallemand yeast docs on the HomeBrew Digest a few years ago: https://hbd.org/hbd/...814.html#4814-4

[Slainte]

I am well aware of the conventional wisdom here, but also have seen scientific studies that indicate otherwise, and have very strong suspicions that breweries are in fact doing this.

Can you share these sources?

[DigitalTaper]

Not a scientific study, but this seems to jive with some things I've read of ProBrewer. Multiple does of O2 by the pro's seem to be the norm for big beers like Barley Wines ... etc.https://www.brewings...rue_false.htm#8

9) Re-aerating a "stuck" fermentation is always a bad idea.9) FALSE If the wort gravity has dropped less than 30% towards its final gravity, it is safe to re-aerate. This is sometimes the only way to recommence fermentation activity. Yeast will remove added oxygen from the fermenting wort, and so the second aeration will not contribute to oxidative potential in the finished product.

[zymot]

Several years ago, there was an interview by a big wig from one of the large yeast manufacturer. (I forget specifics)He recommended that you oxygenate when you first pitch the yeast and to re-oxygenate 12-14 hours later.zymot

[Jimmy James]

Can you share these sources?

Applied and Environmental Microbiology v69 (1) 113-21i can find more if you dig that one.

[Jimmy James]

This was discussed with some of the Lallemand yeast docs on the HomeBrew Digest a few years ago: https://hbd.org/hbd/...814.html#4814-4

Interesting link. It seems that more than a few people around here are aware of possible benefits to oxygenation after fermentation has begun. Given that yeast can consume oxygen even when in the stationary phase it would seem many of our fears about oxygen could be misplaced.

[cj in j]

We don’t oxygenate once the yeast is pitched, but it’s something I want to try with one of our big beers this year or next.

[Stout_fan]

I can say that DuClaw does. 1200 gal batch size.