Better Aeration = Better Attenuation

[Hawkbox]

I just pour the wort in the fermentor and carry it inside. I don't put any special effort into it.

 

[J A]

Aquarium pump running through aeration stone for at least 15 minutes or O2 bubbling for 30 seconds per 5 gallons.
I bought an aquarium pump but never used it. I was concerned that concentrating the air from the surrounding environment was also concentrating the number of potential pathogens. Yes, you have to filter it, but I just didn't trust it.
I got a red Bernzomatic O2 bottle from Home Depot and a valve for 29 bucks and never looked back. If you're using it properly, one O2 bottle lasts for a lot of batches.

 

[Mase]

The fall from the Boil Kettle Valve to the bottom of the fermenter is all the aeration I’ve ever given and I average over 80% attenuation consistently.

I think there’s a good bit more to attenuation than aeration. A good yeast starter and timing of the yeast starter is equally important. I’m usually 18 hours from yeast starter to pitch. I usually, save for the last brew, see fermentation within 2-3 hours of pitch, so there’s plenty of oxygen for the yeast to do their thing.

Generally speaking, 90% of a good beer can be achieved by regular easy practices (as my wife always says), timing, technique and temperature. It’s the last 5-10% that the expense/effort can be a steep climb.

 

[ChicoBrewer]

Do you get the same attenuation with high abv beers? I don't fus much with ales I just splash it while transferring from the kettle. I do use pure oxygen for my stouts

 

[Mase]

The highest ABV I’ve brewed was around 7%.

 

[Hawkbox]

I've done a couple 10% RIS and had no real issues with them. I don't particularly like that style so I can't say if they turned out when or not though.

 

[ChicoBrewer]

I have a 10.5 stout in secondary. Been there almost six weeks. Bottling tomorrow. It's the first and only time I used oxygen. The fermentation was ferocious and I hit my target fg. Attenuation ws 77%

 

[J A]

Attenuation ws 77%

For "Ten-Fiddy" that's good attenuation!

 

[AHarper]

Can you oxygenate AFTER pitching? I gave my latest batch a good shoogle but fear it needs more. It's bubbling but not as violent as I would like.

 

[Hogarthe]

Can you oxygenate AFTER pitching? I gave my latest batch a good shoogle but fear it needs more. It's bubbling but not as violent as I would like.

Depends on how long after and how high gravity. High gravity beers can benefit from a second aeration 18-24 hours after pitching. But I'd be afraid to do it later than that. The yeast might not use it all up and you'll have off flavors.

 

[Nosybear]

Can you oxygenate AFTER pitching? I gave my latest batch a good shoogle but fear it needs more. It's bubbling but not as violent as I would like.

Oxygenate? No. Pure oxygen is poisonous to yeast. Aerate? Yes. Shaking the carboy with yeast in suspension won't hurt anything, caveat, don't do it after fermentation starts due to oxidation concerns.

 

[AHarper]

Oxygenate? No. Pure oxygen is poisonous to yeast. Aerate? Yes. Shaking the carboy with yeast in suspension won't hurt anything, caveat, don't do it after fermentation starts due to oxidation concerns.

too late then... as it just started bubbling so.. what will be will beer...
mmm not bad T-Shirt that... I'm Claiming rights to it now..

 

[J A]

Oxygenate? No. Pure oxygen is poisonous to yeast.

That's an overstatement and doesn't necessarily reflect the reality of the role of O2 in brewing. Nosy is correct in concept as regards the question, though...for most beers, you definitely wouldn't want to add any O2 after fermentation has commenced.
Adding the proper amount of pure O2 to wort shouldn't by any means poison the yeast present. It is possible to over-oxygenate, for sure, but I don't think it would be easy and maybe not even possible with available equipment to get saturation levels that would be fatal to the yeast outright.
Some brewers pitch then oxygenate (directly after the yeast pitch), though I think it's more common to bubble in the O2 first. Some methods for brewing very high-gravity beer call for adding oxygen after fermentation has started in order to boost reproduction and insure higher cell count for optimal attenuation.
Without a way to measure oxygen saturation, it's best to stick with an established regimen to avoid over-oxygenation. It's widely accepted that pure 02 bubbled through an aeration stone at a rate that allows tiny bubbles to dissipate before reaching the surface of the wort for about 30 seconds per 5 gallons of wort will result in O2 levels that will allow for healthy reproduction. Any excess oxygen will be driven out of suspension by the action of natural agitation and CO2 production during active fermentation.

 

[HighVoltageMan!]

Some brewers pitch then oxygenate (directly after the yeast pitch),

That's what I do, I pitch the yeast and then aerate with pure O2. It works great, the agitation from the oxygen mixes the yeast into the wort. The yeast are present at the time of the oxygen getting injected and the yeast will immediately begin to take in the oxygen. Levels of oxygen need to get to 40ppm or higher to harm yeast and even then it's doubtful much harm would be done for two reasons:

• 1- It's extremely difficult to get that much oxygen into the wort, you may have to inject oxygen for 5-10 minutes, which is a severe waste of oxygen and even then it may not get that high. Oxygen doesn't dissolve into a liquid very readily, this is especially true for higher gravity worts, the higher the gravity the less oxygen will dissolve into solution.
• 2- It wants to come out of solution almost immediately. Smaller amounts will remain that are bound up in the wort, which the yeast will metabolize. I read that some pros will aerate the yeast slurry directly with pure oxygen to reduce the amount of oxygen they use in the brewery with good results.

This is a write up by Wyeast about aeration: http://www.wyeastlab.com/oxygenation

It shows that 60 seconds of oxygen injected with a scinter stone produces 12ppm of oxygen. I inject oxygen with that same method anywhere from 60 to 120 seconds depending on whether it's an ale or lager. I just let the wort bubble gently, letting the excess oxygen gas off and fill the carboy head space. Simple and very effective.

 

[Ward Chillington]

I have been using an airstone and o2 for about 6 months now but I don't really have anything to compare it to as I don't recall any huge difference other than realizing that o2 canisters have a reverse thread on them! I built a simple wand with a 12" length of 14 gauge copper wire that I slip inside the plastic hose that attaches to the tank. I have an inline HEPA filter too. The whole rig was pieced together for about 30 bucks I think and does not have any gages so I just shoot the slightest amount of gas to produce a small bubble for about 30 seconds which yields about 3 " of foam to the top of the wort. Based on all those "abouts", you can see that I really scienced the hell out of it!

What I am curious about it how you folks calculated your attenuation?

 

[Nosybear]

I have been using an airstone and o2 for about 6 months now but I don't really have anything to compare it to as I don't recall any huge difference other than realizing that o2 canisters have a reverse thread on them! I built a simple wand with a 12" length of 14 gauge copper wire that I slip inside the plastic hose that attaches to the tank. I have an inline HEPA filter too. The whole rig was pieced together for about 30 bucks I think and does not have any gages so I just shoot the slightest amount of gas to produce a small bubble for about 30 seconds which yields about 3 " of foam to the top of the wort. Based on all those "abouts", you can see that I really scienced the hell out of it!

What I am curious about it how you folks calculated your attenuation?

Oxygenation: I did some math and high-school chemistry and, using my regulator, oxygenate slowly - 1/32 LPM for 8 to 12 minutes, depending on the beer and the gravity. Rationale: Those big bubbles are oxygen that is going into the air, not your beer. A slow stream of fine bubbles dissolves more of the oxygen (displacing air). Basic calculation based on 6,000' elevation is that one minute at 1/32 lpm is approximately 1 ppm of dissolved oxygen.

 

[HighVoltageMan!]

Oxygenation: I did some math and high-school chemistry and, using my regulator, oxygenate slowly - 1/32 LPM for 8 to 12 minutes, depending on the beer and the gravity. Rationale: Those big bubbles are oxygen that is going into the air, not your beer. A slow stream of fine bubbles dissolves more of the oxygen (displacing air). Basic calculation based on 6,000' elevation is that one minute at 1/32 lpm is approximately 1 ppm of dissolved oxygen.

Wyeast did a study that I put a link to up above and they used a scintered stone presumably 1-2 micron. It doesn't have to flow that slow, 90 -120 seconds would be the most it would need and 15 ppm can be achieved in that amount of time. I think it's important to use a stone to produce very fine bubbles to increase the surface area of the gas getting injected into the wort. Altitude will affect these numbers.

Math aside, the best way to check for the amount of oxygen in wort is with a dissolved oxygen meter, which someone from my homebrew club has and verified Wyeast results. The excess oxygen is gassed off, so the flow can be just enough to produce bubbles. The head space of fermenter would be oxygen rich, some of which would be absorbed back into the wort.

What I am curious about it how you folks calculated your attenuation?

Subtract you FG from your OG, take that number and divide it by the OG. Example: 1.050 OG 1.010 FG. 50-10=40. 40/50= .8 or 80%.

 

[Craigerrr]

Responding to this thread in order to bring it back to the top.

To date I have been rocking the carboy to oxygenate the wort. I have a neipa that I recently kegged and the fruity flavors are kind of flat, it is a good beer, but it is not great. It attenuated well enough, but I wonder if lack of oxygen has affected the flavor.

 

[Hogarthe]

I'm not sure lack of oxygen lowers fruity ne IPA flavors. My first guess would be hop types and hop schedule. I could be wrong and proper aeration never hurts so upgrading your aeration method might not be a bad idea even if it doesn't affect it.

 

[BOB357]

I use an aquarium pump, sterile filter and a .5 micron SS stone. Not sure of the pump output, ,but it's rated for 20 to 40 gallon aquariums. I aerate for 20 minutes and my fermentations are quick starting and strong with most being fully attenuated in 3 to 5 days.