Adding Oxygen Prior to Pitching Yeast

I've had some really bad luck with 10-gallon batches during the past year. This obviously gets really expensive when you have to toss 2x the amount of ingredients. With a five gallon carboy, it's not too difficult to pick the thing up and shake the heck out of it. A big batch in a conical fermenter is a different breed of cat. I think my problem has been that I inject too much oxygen, and maybe too vigorously. How would I know? I get what looks like a normal fermentation, but the beer is horrid. I've gone back to making five-gallon batches and haven't had any problems. So, I think I've isolated my 10-gallon problem to an incorrect procedure for adding oxygen in the conical.

If you're shaking and splashing around a ten gallon fermenter, then there is no possible way to get too much oxygen in your wort.  The only way to get too much oxygen in wort, is to use an oxygen tank and pump pure O2 into your wort.  When you put pure O2 in with a diffuser stone, then you can get too much.  If you use an aquarium pump with a diffuser stone (which is putting regular atmospheric air in the form of ... by volume, dry air contains 78.09% nitrogen, 20.95% oxygen,[1] 0.93% argon, 0.039% carbon dioxide, and small amounts of other gases.), you can't get too much oxygen. 

•Shaking/Agitation/Splashing for 40 seconds = 8 ppm max
•Aquarium pump with a diffusion stone for 5 min (using air, which is 20.95% oxygen) = 8 ppm max
•Pure oxygen in a pressurized tank with a diffusion stone for 60 seconds = 0-26 ppm

While most yeast strains have individual oxygen requirements, the average amount needed for a healthy fermentation (SG < 1.065) is between 7 to 18 ppm (around 10 ppm). With pure O2, you can get up to 26 ppm.

Yeast use all availible oxygen in the first 3-9 hours. As long as you are doing a 1 or 2 time dose and are not running pure oxygen on a continuous basis, there is no real danger of over-oxygenating, only under-oxygenating.

You don't really say how you're adding your oxygen with the 10 gallon batches.  If you're using pure O2, then you could be over-oxygenating.  If you're still trying to manhandle 10 gallons to splash it around, then your issue is not over-oxygenation.

How long do you pump regular air or O2 is as follows:

An apparatus diffusing air into chilled (< 70 °F/21 °C) wort typically needs to run for a minimum of 15 minutes to achieve adequate oxygenation, where the same set-up using pure oxygen would require only a minute or two at the most to achieve the same result.

I hope that you found this helpful.

Scott, what is your advice for length of time, in seconds, to add pure O2 to a 5 gal batch of Lager, SG less than 1060?  A 5 gal batch of Ale, SG less than 1060?  (I am adding at 1L/min flow) 

ATPilsHunter said:

Scott, what is your advice for length of time, in seconds, to add pure O2 to a 5 gal batch of Lager, SG less than 1060?  A 5 gal batch of Ale, SG less than 1060?  (I am adding at 1L/min flow)

Click to expand...

I use an aquarium pump and have never used pure O2.  I got all of that information from my brewing library (I read a lot!!!).

Someone here that uses pure O2 will be a better source to answer that.  I'll leave that up to them, as I don't want to just make a guess.

My procedure for my aquarium pump (I'm aware that you didn't ask about that, but someone else might be wondering), is to give it 23 minutes for wort under 1.060 and 30 minutes for wort above 1.060.

Thanks, Scott. I use a stone and can of pure oxygen. I'm absolutely convinced this is what I'm doing wrong. Prior to oxygenating a 10-gallon batch, I never had a problem. Truth of the matter is the light bulb went on when I was watching Brad and John's all grain video. Other than that, I started thinking I might have bugs in my chill plate, but I usually clean that before and after use. I also toss it in the kettle when I'm heating the sparge water.

I use stone and pure O2 and turn the regulator until a you see a steady stream of bubbles.  Don't turn it on all the way where a bunch of gargling is going on...you're just wasting the oxygen.  I aerate mine for about a minute.

Mark

Stone/O2 user.  I turn mine on until I see a steady stream of bubbles and then cut it back to get a fine stream.  I let it flow for about 40 to 45 seconds.

Mike,  You say your beer is horrible, if you can give a better description it may help someone pinpoint the problem better.  You don't describe how exactly your oxygenating your conical.  According to The Yeast Book, the rate is, using a .5 micron stone delivered at 1 liter/minute in 20 liters of 1.077 wort you get 9.2 ppm in 60 seconds and 14.08 ppm in 90 seconds.  Not sure if its linear but I would just scale it up if I was guessing.  They say the goal is to hit 8-10 ppm, but a very respected brewer on this board recommends 12 ppm.  Flow meters can be had from Williams brewing, they call it Big Oxygen, but you can get the regulator alone at amazon.  I do 10 G too, but split into 2 5G carboys and I shut off the flow at about 1 minute and leave it in the carboy till the residual air in the line stops the stone from bubbling.  This will take it another 15-20 seconds to stop.

From the outside looking in I am gonna go on a limb and say its maybe not your oxygenation rate.  It makes a difference but probably not enough to make a beer horrible.  A lot of people on here don't oxygenate at all and the Yeast Book says most commercial brewers are way off but they still produce some darn fine beer.

I am guessing you are using the same equipment for 5's and 10's, tuns, ketttles, tubing, chiller, etc.  The outlier is your conical.  I would break it down as far as possible and give it a 170F PBW cleaning til its pristine.  Nobody likes to think its a cleaning problem, but horrible points in that direction.  To me, anyway.

Its easy to laser in one thing, I am guilty of that often, but O2 levels shouldn't be the difference between horrible and what your used to.

I agree with KernalCrush.  Over-oxygenation may cause some issues, but truly horrid beer is not an automatic consequence of it. 

Seems more likely that some component of the conical is dirty/buggy, and tearing it down to individual pieces may help.  Or any other piece that you use when using the conical that you don' t use with the 5-gallon, like a different length of tubing. 

I always tear down all the valves after brewing since finding sweet wort and hop bits behind the ball in a valve I had swished around in Oxyclean and toggled the lever.  Still had gunk inside.  If a valve sits like this for a month, and then the next batch flows through it on the way to the fermentor?  Not good.

Its strange with the valve cleaning, the kettle valves always fair much worse than the chiller or any other valve for me, When I clean kettle valves I wish I had done it much sooner, the rest of them I wish I hadn't taken them apart cause they didn't need it.

Agreed.  The kettle valve is worse than my MLT, and MLT is preboil, so perhaps less vital to clean, but I use just two valves so it's little additional work.

I really do appreciate the advice and suggestions. I've thought about bugs existing in valves ... and even the side valve on my Blichman conical. Both valves really need to be removed, taken apart, and cleaned. I got lazy because I was having a problem with a small leak at the bottom. I started racking the beer instead of letting it exit the bottom valve after fermentation. I was actually more satisfied with clarity by doing it this way. Then I just washed the heck out of the conical. I always run StarSan through the conical before transferring chilled wort to it. I'm going to brew a 10-gallon batch today, but my plan is to split the volume into two carboys. Then shake the peejazus out of them before splitting and adding yeast from the starter I made over the weekend. I can almost guarantee I will have success doing it this way, but it sickens me to see my ss conical not being used as it should be.

Thanks Guys

I have found this post to be very informative. I believe that I have been suffering from the opposite problem that Mike believes he has. Since transitioning to all grain over the past 16 months I my infection rate has increased ten fold. I have put this down to sluggish yeast, slow to start and quick to drop out. I have decided that it is a lack of oxygen and have finally purchased an aquarium pump and air stone.
Looking forward to seeing more of those healthy Krausens that I used to get with extract and partial mash brewing.

Cheers & Beers

The latest info I have for O2 is: 

splashing=4 ppm
'lots' of vigorous shaking= 8ppm
pump & stone = 8ppm
They say 8 ppm is the maximum you can get using air of any method even with a pump and stone and times of forever.
They go on to say that extended pump & stone aeration will result in loss of head formation & retention. 
overoxygentation will get you acetaldehyde and fusels
underoxygenation will get cause lack of and slow attenuation, off-flavors, and decreased health for re-use.

Hey KernelCrush

Once I became aware of my issue, I tried splashing the wort aound as came out of the plate chiller, and then a vigorous stir. Your reading of 4ppm makes sense, it worked better and I didn't loose the brew. However the fermentation wasn't as vigorous as I am used to, very small Krausen layer for a very short time.

Cheers

Low o2 levels of 4ppm can lead to exactly what you describe.  If you can get a O2 bottle and flush your headspace with 02 then shake vigorously, you can get up to 10ppm, but at that point you might as well get a stone to deliver the o2.  Then you may as well get a flow metre to govern and time it.  Then you may as well go to the airport and get aviator oxygen for purity.  Then...it never stops.