Pure O2 = extreme lag

I made the switch to oxygen to aerate my wort about a dozen batches ago and ever since I've had problems. My beers are either slow to start fermenting or finish high, or both.

I brewed an IPA yesterday and aerated with 02 for a minute and a half at a rate of .6L/min through a 2 micron stone. I use buckets to ferment in and there was a layer of foam on the wort; but I could tell there was a small amount of bubbles reaching the surface. I pitched a rehydrated packet of US-05 20 hours ago and still no activity. Shouldn't there be a violent fermentation happening by now? Am I not using enough O2? I have tried using a lower rate for a longer duration with mixed results.

Help!

According to what I've read, oxygenation of the wort isn't super neccessary with fermentis dry yeasts. However, I aerate quite well during chilling and funnel into the carboy through a mesh filter. I assume that my wort is well aerated but I also don't usually have lag times that long. What was the gravity of the wort you pitched into?

-Also, I don't advocate not oxygenating wort and I always aerate in some fashion. I am purely regurgitating information I have read.

What are you using to judge that there is no fermentation?

At 20 hours with plenty of oxygen you may simply have missed the most vigorous portion of fermentation. You actually don't need to oxygenate as vigorously with dry yeast, but you didn't hurt anything. Oxygen is only going to reduce your lag times and speed up fermentation, so don't worry too much about it.

What are your gravity readings that lead you to believe there's been no fermentation?

take a hydro sample and see where it stands..

I pitch rehydrated 05 at around 62 deg and it takes around 24 hrs to start going.

20 hours is not extreme lag. I would file it under "typical."

If you are using your airlock to gauge fermentation activity, 1) don't and 2) you are really measuring the length of time the yeast takes to fill up the headspace in the fermenter with dense CO2. If a nervous homebrewer keeps "checking" on things (opening, wiggling airlock, hugging, praying), he or she will likely vent some of the positive pressure, thus delaying airlock activity.

Test the gravity or leave it alone. There's nothing you can do to force yeast to eat carbohydrates.

Getting more O2 into your wort WILL increase lag times because they yeast stays in a reproductive stage longer, not going anaerobic.

In terms of yeast health, I think the best thing to do would be to pitch like a 1 gallon starter into 4 gallons of beer while the yeast is at high krausen. But of course, you know that would totally change the taste of your beer. So you allow the yeast to reproduce a bit in the beer, consuming O2, before entering the anaerobic phase. Add too much O2 and the yeast spend more time reproducing, hence more lag time.

I too have noticed that my pure-O2 beers have a longer lag time. But that they also have a very fast and aggressive fermentation. If the long lag time is bothering you, use the O2 to make a massive starter and aerate less into the wort. I can't say it'll make your beer better, but it'll decrease your lag time for sure!

If you're usising dry yeast then aeation is going to have less of an impact since the dry yeast contains enough lipids required for the cell walls or whatever.

Not experiencing longer lag times since I started using pure O2 to oxygenate my wort (some time ago). I typically get active fermentation sign within 12 hours of pitching the slurry (I make starters, cold crash, decant and pitch JUST the yeast slurry). More than a few times I've needed to connect a blow-off tube not long after that.

I'm using 1-2LpM of pure O2 for anywhere from 60-120 seconds, typically. I hit my high OG barleywine batch with 1.5LpM for just over 3 minutes and it was pushing through the blow-off tube in under 12 hours. :rockin:

I think you might not be using enough pure O2 for your wort. I also wonder how you got the .6LpM number. I've yet to see any O2 regulators that go to that fine an indicator. I've been using one with the floating indicator, with 1/4LpM graduations on it. I also have another that's has a knob you turn to get a set O2 LpM flow.

Sir Humpsalot said:

Getting more O2 into your wort WILL increase lag times because they yeast stays in a reproductive stage longer, not going anaerobic.

In terms of yeast health, I think the best thing to do would be to pitch like a 1 gallon starter into 4 gallons of beer while the yeast is at high krausen. But of course, you know that would totally change the taste of your beer. So you allow the yeast to reproduce a bit in the beer, consuming O2, before entering the anaerobic phase. Add too much O2 and the yeast spend more time reproducing, hence more lag time.

I too have noticed that my pure-O2 beers have a longer lag time. But that they also have a very fast and aggressive fermentation. If the long lag time is bothering you, use the O2 to make a massive starter and aerate less into the wort. I can't say it'll make your beer better, but it'll decrease your lag time for sure!

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+1. I was going to say the exact same thing but Sir Humpsalot has it covered.

I typically use .25 lpm (as my medical reg shows) for 60 seconds. Yes, pure O2 will extend lag time by a few hours but it catches up.

Of course this is just one experiment, but I trusted the results.

https://www.youtube.com/watch?v=vOrfmzpDmPk&list=UURBBPlmq3OnbhiOm7EshI3g&index=57&feature=plcp

Thanks for all of the responses. I pitched the yeast 48 hours ago and the gravity has fallen from 15.5P to 12.5P. The sample tastes really good. From the responses this may be normal but maybe not. And I should use more 02 but possibly less.

I had similar problems when I first started using O2, so I switched to just O. I saw drastically reduced lag times and unusually vigorous fermentation. I'd never go back to O2 now.

osagedr said:

I had similar problems when I first started using O2, so I switched to just O. I saw drastically reduced lag times and unusually vigorous fermentation. I'd never go back to O2 now.

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What is your source for straight O (oxygen) instead of O2?

In the book "Yeast", Chris White explains why short lag times are not ideal and longer lag times may actually be ideal in certain situations.

msa8967 said:

What is your source for straight O (oxygen) instead of O2?

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Lol. Trolld.

What's wrong with O3?

sudsmcgee said:

What's wrong with O3?

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You may be onto something. You can rent ozone generators pretty cheap, or budget-brewers could plumb into their Sharper Image Ionic Breeze air purifier.

Not sure what the additional O will do to lag time.

SpeedYellow said:

You may be onto something. You can rent ozone generators pretty cheap, or budget-brewers could plumb into their Sharper Image Ionic Breeze air purifier.

Not sure what the additional O will do to lag time.

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Who cares about the effect on lag time. With O3 (ozone) you can sleep soundly knowing that your fermenting beer has an extra layer of protection from harmfull UV rays.

I didn't even think about that! Plus ozone clears bad odors from the air. Your beer will smell fresh and clean!

After 72 hours from pitching, gravity was at 10.5P. Lack of 02 has to be the reason. I'm going to try 1L/min for 2 minutes next time.

I read on another forum that O4 was pretty good. Haven't had much luck with it myself though. Long lag times etc.

Meh don't worry about lag times. It's not 1996 anymore.

Surprised this hasn't been mentioned but I understand pure o2 is best used with a .5 micron stone, not a 2 micron.