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bodhisatta 
Smurf real estate agent


Registered: 04/30/13
Posts: 61,890
Loc: Milky way
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Oxygen doesn't increase the speed of yeast growth. They use it to synthesize sterols for their cell walls when they're in growth phase. Oxygen is very toxic to yeast, thats why most yeast propegators use air rather than O2 unless youre a rich brewery and can dial that shit in pdrfect and measure disolved oxygen. actually too high of co2 levels is also lethal as too high of O2. Pretty much they enjoy normal earth conditions
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bodhisatta 
Smurf real estate agent


Registered: 04/30/13
Posts: 61,890
Loc: Milky way
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Re: Oxygen or Co2? need an urgent answer [Re: spacechildo]
#21739935 - 05/30/15 06:49 AM (8 years, 8 months ago) |
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Quote:
spacechildo said:
Quote:
rxb said: for instance... soda isnt h2co3 its h2o+co2
pretty sure its both man. carbonic acid in water will be in equilibrium and create hco3-, h3o+ and co3(2-) and go back again, done in 2 steps.
Carbonic acid is created but even if you shake the fuck out of soda or beer the carbonic acid stays. Any carbonic acid you make from carbonation stays in solution even if you degas the liquid. Carbonic acid will drive the PH down a little but titratable acidity will go up quite a bit.
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freeofcharge
Stranger

Registered: 05/24/15
Posts: 39
Last seen: 6 years, 3 months
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Re: Oxygen or Co2? need an urgent answer [Re: bodhisatta]
#21740568 - 05/30/15 10:42 AM (8 years, 8 months ago) |
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Quote:
bodhisatta said: Oxygen doesn't increase the speed of yeast growth. They use it to synthesize sterols for their cell walls when they're in growth phase. Oxygen is very toxic to yeast, thats why most yeast propegators use air rather than O2 unless youre a rich brewery and can dial that shit in pdrfect and measure disolved oxygen. actually too high of co2 levels is also lethal as too high of O2. Pretty much they enjoy normal earth conditions
"It is generally safe to assume that you need at least 10ppm of oxygen. 10ppm will supply adequate oxygen in most situations. Over-oxygenation is generally not a concern as the yeast will use all available oxygen within 3 to 9 hours of pitching and oxygen will come out of solution during that time as well. Under-oxygenation is a much bigger concern."
Edited by freeofcharge (05/30/15 10:43 AM)
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bodhisatta 
Smurf real estate agent


Registered: 04/30/13
Posts: 61,890
Loc: Milky way
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Re: Oxygen or Co2? need an urgent answer [Re: freeofcharge]
#21740635 - 05/30/15 11:03 AM (8 years, 8 months ago) |
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they use it a lot quicker than that.
I've cleaned up wyeast cultures before that have come less than pure. White labs is far more reliable at least the person who runs that company has a phd and expertise in microbiology. most of my job is running yeast propagation
oxygen doesn't come out of solution during that time at a measly 10ppm. oxygen is extremely soluble in de-airated wort at 68F
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bodhisatta 
Smurf real estate agent


Registered: 04/30/13
Posts: 61,890
Loc: Milky way
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Re: Oxygen or Co2? need an urgent answer [Re: bodhisatta]
#21740640 - 05/30/15 11:05 AM (8 years, 8 months ago) |
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Quote:
bodhisatta said: growing yeast for brewing isn't as easy as you would think. it's far more easy to keep fermentations moving along and reusing and possibly washing the yeast. you can do that for 20 generations if you're very clean and your handling techniques are spot on every time
even doing that most breweries run into rampant contamination and find themselves buying new pitches or using dry yeast eventually. it's really not that easy to get your shit together well enough without a dedicated full time lab department and well trained cellermen and brewers.

wild yeast like this canada albicans species(yeast infection quite literally) can show up as well as plenty of anaerobic bacteria if you look closely you can see a pseudo hyphae in the C.albicans it's an interesting species of yeast as it can be both yeast like and "Fungus like" it has yeast, pseudo hyphae, and actual hyphae morphologies depending.

 bacteria are a real problem too, they're much easier to grow and keep around than yeast.
the requirements for good yeast growth to get counts getting above 109 cells per mL are stringent, during propagation you use oxygen for cell wall synthesis. most breweries cant handle self sustained yeast propagation you have to get into the 100,000+ bbl/year range for most breweries to get to the point of being able to get that program going.
I highly suspect the quality of LC varies hugely among hobby growers here on the shroomery due to LC growing conditions, DO, and nutrient contents. either way the result is if you put any living mycelium in a jar it will take off.
There was one brewery I was talking with that house fabricated a prop tank for trying to get yeast independent. they had a large version of a magnetic stir plate and stir bar to keep the yeast agitated during prop. the internal stir element destroyed yeast and dropped their viability by some 30% alfa laval solved this problem and makes a magnetic levitate agitator now that keeps yeast from lysis.
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Jenn
Supreme Leader



Registered: 04/27/15
Posts: 200
Last seen: 8 years, 4 days
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Re: Oxygen or Co2? need an urgent answer [Re: bodhisatta] 1
#21740653 - 05/30/15 11:10 AM (8 years, 8 months ago) |
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Use Brawndo. It has electrolytes.
-------------------- Sit down before fact as a little child, be prepared to give up every preconceived notion, follow humbly wherever and to whatever abysses nature leads, or you shall learn nothing.
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bodhisatta 
Smurf real estate agent


Registered: 04/30/13
Posts: 61,890
Loc: Milky way
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Re: Oxygen or Co2? need an urgent answer [Re: Jenn] 1
#21740658 - 05/30/15 11:11 AM (8 years, 8 months ago) |
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it's what yeast want.
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