Just read an interesting blog about oxygenating wort. Seems if you over oxygenate, you run the risk of producing too many fusel alcohols and/or your beer becomes too "boozy". 1liter/minute for 1 minute thru an aeration stone is recommended for anything under 1.070.
I have just been dunking the stone and cranking up the O2 for about 30-60 sec. I have noticed my beers being a little "hot" occasionally and attenuating further than expected.
Over oxygenation
Over oxygenation
John Buck
Brother John's Brewing
The Monk at the Hartley Monastary
Brother John's Brewing
The Monk at the Hartley Monastary
Over oxygenation
The Jamil & Chris White "Yeast" book indicate that "too much oxygen" can increase fusel alcohols & acetaldehyde and will reduce ester production, but they don't indicate what "too much" means. They do state that "too much oxygen" is rarely a problem and suggest 8-10 ppm for most yeast. Keep in mind a couple of things here.
1. The "right amount" is a function of pitching rate. If you're just pitching a single vial/pack of yeast, I suspect it's easier to have "too much" oxygen than if you're following the pitching rate guidelines & making a starter.
2. For most beers, I seriously doubt any of us are over-oxygenating. I've been tracking DO for various means of aeration for the past year & have found it damn near impossible to get more than 16 ppm DO with an oxygen bottle & diffusion stone.
3. Any amount of DO over 8 ppm will gradually dissipate as the solution will have more DO than is possible with air & the excess oxygen will equilibrate to atmospheric conditions. I'm not sure what the dissipation rate is, but I bet it will approach 8 ppm during the yeast growth phase.
I probably have enough data to do a Tech Topic on aeration methods if you guys are interested. I only have a couple of data points using an aquarium pump, but it seems very consistent so far & is probably safe to share. I have 10 data sets for the "purge & shake" method & 10 for the "O2 bottle & aeration stone". There is some variation, but I think there's enough data to show a meaningful trend. I would like to follow this up with a "how much do I need?" set of experiments.
If you're getting yeast-derived off flavors, I would look at pitching rates & temp before oxygen (assuming you're aerating at all).
On Saturday, April 13, 2013, bf514921 wrote:
1. The "right amount" is a function of pitching rate. If you're just pitching a single vial/pack of yeast, I suspect it's easier to have "too much" oxygen than if you're following the pitching rate guidelines & making a starter.
2. For most beers, I seriously doubt any of us are over-oxygenating. I've been tracking DO for various means of aeration for the past year & have found it damn near impossible to get more than 16 ppm DO with an oxygen bottle & diffusion stone.
3. Any amount of DO over 8 ppm will gradually dissipate as the solution will have more DO than is possible with air & the excess oxygen will equilibrate to atmospheric conditions. I'm not sure what the dissipation rate is, but I bet it will approach 8 ppm during the yeast growth phase.
I probably have enough data to do a Tech Topic on aeration methods if you guys are interested. I only have a couple of data points using an aquarium pump, but it seems very consistent so far & is probably safe to share. I have 10 data sets for the "purge & shake" method & 10 for the "O2 bottle & aeration stone". There is some variation, but I think there's enough data to show a meaningful trend. I would like to follow this up with a "how much do I need?" set of experiments.
If you're getting yeast-derived off flavors, I would look at pitching rates & temp before oxygen (assuming you're aerating at all).
On Saturday, April 13, 2013, bf514921 wrote:
Post generated using Mail2Forum (http://www.mail2forum.com)i remeber a few times on he jamiel show talking about over oxegytion. I dont oxegrnate, but remeber the "fuelsol and hot satement"
Brandon Franklin - The other Franklin
I agree with the good Dr. Most information I have found says that a homebrewer is rarely going get too much O2 and should not worry about it.
Matt Franklin
Slappy Brewing North
On Tap:
American IPA
Strata Hazy IPA
Dr. Lee Orval
American Strong Ale
Friend of the Devil Belgian Golden Strong
Imperial Stout
Slappy Brewing North
On Tap:
American IPA
Strata Hazy IPA
Dr. Lee Orval
American Strong Ale
Friend of the Devil Belgian Golden Strong
Imperial Stout