indianaroller

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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!

KraphtBier

Recipes 

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.

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

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daksin

Recipes 

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?

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tally350z

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take a hydro sample and see where it stands..

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beerman0001

Recipes 

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

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Franc103

Recipes 

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.

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Sir Humpsalot

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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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rshortt

Recipes 

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.

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Golddiggie

Recipes 

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.

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.

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