Page 1 of 2 12 LastLast
Results 1 to 15 of 18

Thread: oxygen: When to say when?

  1. #1
    Join Date
    Mar 2006
    Posts
    189

    oxygen: When to say when?

    Thanks to all who answered my filtration questions! Problem solved! Beer to warm on outlet side! Thanks.
    I set my oxygen regulator (made by a mediacal company) to 6 LPM. It's enough to produce a steady flow through the wort in the sight glass. Ideally, for my yeast strain, I want to inject 1 liter of oxygen per Bbl.. This being so, according to my "trusty" regulator, I would only need to run the Oxygen for 1 minute+ for my usual 7 Bbl batch. That just doesn't seem right to me, since all of the brewers who came before me would keep the oxygen running for an arbitrary amount of time, at least 2/3 the time it took to knock out. I ws told by one that because it is a medical regulator, it is not necessarily accurate. If this is so, how will I ever know I am using the correct desired amount of oxygen? Your input is greatly appreciated!

  2. #2
    Join Date
    Mar 2006
    Location
    Germany
    Posts
    184

    Air

    This is probably not an option for you, but if you could get clean compressed air, that would be ideal. Then you couldn't over-oxygenate. Using oxygen can be tricky and many brewers over-oxygenate without knowing it. Their yeast are sluggish or there are off flavors, but they attribute this to other things. Although it may not be immediately noticable in fresh beer, oxygen strips your wort of anti-oxidants, which causes a "cardboard" flavor among other things in aged beer. In a brewpub this may not be so critical, but if you bottle and your beer travels it is. The reactivity of the compounds in the wort with oxygen increases dramatically with increasing temperature. That's why oxygenation should be done at a low temperature.

    Yeast need about 7 or 8 mg of oxygen per liter for normal beers, so not a whole lot (more for high gravity beers). In order to achieve this, but have it evenly distributed throughout the wort, let it bubble slowly into the wort as it passes to the fermenter or pitching tank. If you have a means of measuring the total amount of oxygen you use for a given batch of wort, then you can figure out how much you put in. Of course, some of it doesn't dissolve in the wort. 20 to 30 mg per liter is toxic for yeast.

    Because I didn't have another option, I set the rate just through trial and error by observing flow rates and the pressure guage. If you always have the same wort flow rate then you can set the bubble rate in the sightglass. My yeast always took off really well and never showed signs of over-oxygenation. If you have healthy yeast in the log phase when they're pitched, then you can under-oxygenate a little and not worry. Generally speaking, catering to your yeast's needs helps elminate a lot of problems in the brewery, i.e. take care of the boys and they'll take care of you.
    Last edited by crassbrauer; 04-25-2006 at 04:19 PM.

  3. #3
    Join Date
    Apr 2003
    Location
    Farmville, NC
    Posts
    38

    oxygen

    I believe that what you're really interested in here is the amount of oxygen that actually gets dissolved in the wort. This will vary with temperature of knockout, length of hose run between oxygen injection and receiving vessel, turbulence in the line (are you getting turbulent rather than laminar flow? does the line make sharp corners? etc.), surface area contact of oxygen to wort (are you injecting through a scintered stone?) and other factors. Ultimately, there's no way to know (I believe) exactly what's getting dissolved without the use of a DO meter. Of course, too much oxygen at any given time will cause excessive foaming in the fermenter as well. We used a trial and error approach (measuring, mainly, lag time before active fermentation) and came up with 3.5 L / min over the entire course of our 30 minute knockout (70 F for 20 bbl) for standard gravity beers and 4.5 L / min for high gravity beers. This seems to work well for our set-up, but I'm confident that results will depend on the specifics of your set up. Good luck.

    Paul Philippon
    The Duck-Rabbit Craft Brewery
    Farmville NC
    www.duckrabbitbrewery.com

  4. #4
    Join Date
    Feb 2003
    Location
    Boise, ID
    Posts
    230

    Oxygen

    I second the above post- lots of variables. We use a small stone on the outlet of the heat x, and a 30' 1 1/2" hose to all of our fermenters regardless of their proximity to the heat x., 2 LPM over a 67F 35 min. cool-in for ~11 Bbls works well here. We brew 2 batches to fill most of our fermenters, but not in one day. The next day (2nd brew) needs no air. I have heard that you CAN over-oxygenate with medical grade O2(which we use), but not with filtered compressed air. I have used both in the past with good results.

    Good Luck!

  5. #5
    Join Date
    Nov 2002
    Location
    Polson, Montana, USA
    Posts
    1,256
    Quote Originally Posted by pbutlert
    I have heard that you CAN over-oxygenate with medical grade O2(which we use), but not with filtered compressed air. I have used both in the past with good results. !
    Not to get off subject here, BUT....
    I remember reading in one of my brew books not to use medical grade O2 because it can contain compounds that inhibit bacterial growth and can, therefore, be harmful to your yeast.
    Just my random thoughts from the margin......
    Prost!

  6. #6
    Join Date
    Oct 2003
    Location
    Pittsburgh, PA
    Posts
    404
    Rule of thumb: Look at your yeast volumes, before and after. Too much yeast = too much O2.

    Scott

  7. #7
    Join Date
    Mar 2006
    Location
    Germany
    Posts
    184
    ...or too few yeast (or lots of dead ones) = too much O2.

    You should pitch around 10 - 20 million cell per ml (depending on whether you're brewing with ale or lager yeast); they should reach around 50 - 60 million. If you overpitch and oxygenate, then you'll have too much yeast.

    Oxygen is toxic to living cells in high concentrations. If it weren't for it's essential role as an electron receptor in respiration then you wouldn't want it around, because free radicals damage DNA and, in some cases, cause cancer, hence the need for anti-oxidants in your diet and your beer.
    Last edited by crassbrauer; 04-27-2006 at 02:36 AM.

  8. #8
    Join Date
    Apr 2016
    Location
    Santa Marta, Colombia
    Posts
    8
    Quote Originally Posted by crassbrauer View Post
    This is probably not an option for you, but if you could get clean compressed air, that would be ideal. Then you couldn't over-oxygenate. Using oxygen can be tricky and many brewers over-oxygenate without knowing it. Their yeast are sluggish or there are off flavors, but they attribute this to other things. Although it may not be immediately noticable in fresh beer, oxygen strips your wort of anti-oxidants, which causes a "cardboard" flavor among other things in aged beer. In a brewpub this may not be so critical, but if you bottle and your beer travels it is. The reactivity of the compounds in the wort with oxygen increases dramatically with increasing temperature. That's why oxygenation should be done at a low temperature.

    Yeast need about 7 or 8 mg of oxygen per liter for normal beers, so not a whole lot (more for high gravity beers). In order to achieve this, but have it evenly distributed throughout the wort, let it bubble slowly into the wort as it passes to the fermenter or pitching tank. If you have a means of measuring the total amount of oxygen you use for a given batch of wort, then you can figure out how much you put in. Of course, some of it doesn't dissolve in the wort. 20 to 30 mg per liter is toxic for yeast.

    Because I didn't have another option, I set the rate just through trial and error by observing flow rates and the pressure guage. If you always have the same wort flow rate then you can set the bubble rate in the sightglass. My yeast always took off really well and never showed signs of over-oxygenation. If you have healthy yeast in the log phase when they're pitched, then you can under-oxygenate a little and not worry. Generally speaking, catering to your yeast's needs helps elminate a lot of problems in the brewery, i.e. take care of the boys and they'll take care of you.
    You mention here aerating with clean compressed air. I am interested to start doing it this way as accurately measuring dissolved oxygen levels is not possible right now. 'clean compressed air' can be produced using an oil free compressor. My question is:

    What pressure do you inject the air and for how long? i intend to inject compressed air into the flow or wort as it moves from chiller to fermenter.

  9. #9
    Join Date
    Jan 2003
    Location
    Palau
    Posts
    1,880

    Clean compressed air...

    You can achieve clean compressed air with a typical reciprocating, oil-lubricated compressor. Just use good filtration and an air dryer. Rate of air injection into wort line is not important as long as you get saturation. I read saturation by using same long hose after air injection and keeping bubbles in the sight glass at the fermenter. Again, one of the great things about air is that you cannot oversaturate. And BTW, there's a great book on compressed air in breweries from MBAA, and should be compulsory reading for any serious brewer.
    Phillip Kelm--Palau Brewing Company Manager--

  10. #10
    Join Date
    Nov 2002
    Location
    Mobile, Alabama, USA
    Posts
    185

    Clean compressed air needs a filter

    Dual filter/separator/regulator block

    https://www.amazon.com/PneumaticPlus...lus+PPC3C-N02G

    I plan on running this off of an inexpensive airbrush compressor.

    https://www.harborfreight.com/15-hp-...kit-60328.html
    Todd G Hicks
    BeerDenizen Brewing Services
    Serda Brewing Company
    (Brewery-In-Construction) - Finally!!!

  11. #11
    Join Date
    Oct 2013
    Location
    Dallas, Bangalore and soon Goa
    Posts
    225
    Another good option depending on the size of your brewery and line resistance, is a large aquarium pump.

    You can place a sterile disc filter in line to avoid contaminants, and if it is a diaphragm pump, you usually won't need to worry about oil. Just remember to change the filter occasionally.

    I second (or third, fourth) the air over oxygen, however a pressure regulator with a rotameter does good if you need o2.

  12. #12
    Join Date
    Apr 2017
    Location
    Chapin, SC, US
    Posts
    12
    Quote Originally Posted by Todd Hicks View Post
    Dual filter/separator/regulator block

    https://www.amazon.com/PneumaticPlus...lus+PPC3C-N02G

    I plan on running this off of an inexpensive airbrush compressor.

    https://www.harborfreight.com/15-hp-...kit-60328.html
    +

    Great idea. We currently use O2 but have been thinking about changing to compressed air and this setup looks nice so does the $$. Thanks for sharing
    Angry Fish Brewing Co
    Lake Murray SC
    We Drink All We Can and Sell the Rest

  13. #13
    Join Date
    Apr 2016
    Location
    Santa Marta, Colombia
    Posts
    8
    Quote Originally Posted by dieharduscfan View Post
    +

    Great idea. We currently use O2 but have been thinking about changing to compressed air and this setup looks nice so does the $$. Thanks for sharing
    Hi,

    I am a little undecided if to go o2 or air. I like the idea of the air because you don't need to worry about over oxygenating and also don't need to worry about DO probe.

    I am concerned about the fact that with air you can only acheive a max of about 8ppm where i would prefer to be up near 10ppm.

    What is making you thinking of switching to air over o2?

    Cheers

  14. #14
    Join Date
    Oct 2013
    Location
    Dallas, Bangalore and soon Goa
    Posts
    225
    Quote Originally Posted by Surf Money View Post
    Hi,

    I am a little undecided if to go o2 or air. I like the idea of the air because you don't need to worry about over oxygenating and also don't need to worry about DO probe.

    I am concerned about the fact that with air you can only acheive a max of about 8ppm where i would prefer to be up near 10ppm.

    What is making you thinking of switching to air over o2?

    Cheers
    Out of curiosity, is there a reason you prefer to be up around 10ppm over 8 ppm?

    Most yeast manufacturers recommend a level between 6-8ppm. I literally just confirmed this info from Fermentis today, and used to work for one of the big W liquid yeast companies. (I have had good results with both FYI)

    If you are making 16*P or higher wort, I would certainly agree you need more oxygen. Anywhere between the 10-14ppm range with a single addition. But my experience has told me you are actually better off with a 8ppm concentration with a secondary aeration about 12-24 hours after knock out. This allows the yeast to continue cell production a bit longer without creating an over-active fermentation. Slowing down the fermentation gives the yeast a chance to produce more new cells before converting to ethanol production. An over-active ferment early on can actually increase the odds of an early stall.

    Interesting side note, BitBurger was able to achieve 14ppm DO with compressed air (not oxygen) using a venturi injection system. It's been a few years since I actually looked at the data, but it was a well written piece.

  15. #15
    Join Date
    Apr 2017
    Location
    Chapin, SC, US
    Posts
    12

    Compressed Air vs O2

    Quote Originally Posted by UnFermentable View Post
    Out of curiosity, is there a reason you prefer to be up around 10ppm over 8 ppm?

    Most yeast manufacturers recommend a level between 6-8ppm. I literally just confirmed this info from Fermentis today, and used to work for one of the big W liquid yeast companies. (I have had good results with both FYI)

    If you are making 16*P or higher wort, I would certainly agree you need more oxygen. Anywhere between the 10-14ppm range with a single addition. But my experience has told me you are actually better off with a 8ppm concentration with a secondary aeration about 12-24 hours after knock out. This allows the yeast to continue cell production a bit longer without creating an over-active fermentation. Slowing down the fermentation gives the yeast a chance to produce more new cells before converting to ethanol production. An over-active ferment early on can actually increase the odds of an early stall.

    Interesting side note, BitBurger was able to achieve 14ppm DO with compressed air (not oxygen) using a venturi injection system. It's been a few years since I actually looked at the data, but it was a well written piece.

    I have to agree with Unfermentable about only needing a max of 8ppm of compressed air for beers less than 15*P. I won't get rid of the O2 altogether but only use it in the beers over 15*P which can be monitored as normal. But since most of our beers are below the 7.5% range, it seems using compressed air would be the most practicable way of oxygenating the wort on a day to day basis. The last thing I want to do is find out a batch of beer has an off-flavor probably due to over oxygenating(Tossing a batch of beer is my worst nightmare just FYI). Plus, I liked the design from his post. Small but efficient for a small startup Nano brewery which is where I'm at right now. I may change paths once I grow into a larger brewery and start distributing.
    You have to love the beer discussions on here. I've learned a lot from just reading the articles on here vs. seminars and classes. Keep up the good articles...
    Cheers
    Angry Fish Brewing Co
    Lake Murray SC
    We Drink All We Can and Sell the Rest

Page 1 of 2 12 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •