[Megary]

I'm sure no one here doubts the need for proper oxygenation, I just don't think there is any consensus on the definition of "proper". 
Is there a particular ppm that needs to be met?  For every single brewing situation?  Maybe, but I'd find it hard to believe.

Feels like a Mug's game.

[mchrispen]

For a good long time, most of us went by recommendations that suggested 8-12 ppm, the lower end really about all you can achieve through shaking a heavy fermenter. If I recall, the Yeast book pushed 12 ppm, and recommended a shot of pure O2. B &Q's book on Yeast and Fermentation also recommends 12 ppm, but then go through to prove that it varies, and generally in ways that are beyond a normal homebrewer's capability. The recommendations for a starter apply to most liquid yeast vials/packs, when repitching yeast (including formerly dry yeast).


A couple of things also to consider here:

• Shaken and Not Stirred starters or even so-called Vitality starters are not considered in any of the academic books. It would be nice if one of the big yeast manufacturers would take this up and give some solid lab results.
• If we are claiming O2 uptake is much higher surface ratios because of the homebrew scale - it feels like this should also be applied to our fermentation transfers. I haven't done the math - don't plan to. I imagine we are getting, generally, adequate oxidation for a medium gravity beer in most cases just by a splashy transfer.
• Compared to when I used to get pretty marginal yeast nearly 20 years ago to today, the bar has moved quite a bit. New processes seem to be yielding a more stable delivery of healthy yeast.
• I am a weirdo that from my mead/wine practices uses GoFerm and rehydrates yeast before pitching - and I get consistent results. I do SnS with liquid yeast pitches and only now use pure O2 if my gravity is above 1.065, and only then a day or two into fermentation to keep things going. I know some dry yeast manufacturers now just recommend pitching dry. I just want to make sure that packet is viable.

[Richard]

Note that Denny is now using SNS starters. That process gives the yeast oxygen before pitching it into the beer. Is it enough oxygen? The inventor of the SNS method says yes, but I am not convinced. I think that some kind of aeration during the transfer from kettle to fermenter is still worthwhile. I have a wine-type aerator that I put on the end of my transfer hose. I no longer use oxygen except for very high gravity beers.

[denny]

Note that Denny is now using SNS starters. That process gives the yeast oxygen before pitching it into the beer. Is it enough oxygen? The inventor of the SNS method says yes, but I am not convinced. I think that some kind of aeration during the transfer from kettle to fermenter is still worthwhile. I have a wine-type aerator that I put on the end of my transfer hose. I no longer use oxygen except for very high gravity beers.

Are you not convinced due to your experience?

[denny]

For a good long time, most of us went by recommendations that suggested 8-12 ppm, the lower end really about all you can achieve through shaking a heavy fermenter. If I recall, the Yeast book pushed 12 ppm, and recommended a shot of pure O2. B &Q's book on Yeast and Fermentation also recommends 12 ppm, but then go through to prove that it varies, and generally in ways that are beyond a normal homebrewer's capability. The recommendations for a starter apply to most liquid yeast vials/packs, when repitching yeast (including formerly dry yeast).


A couple of things also to consider here:

• Shaken and Not Stirred starters or even so-called Vitality starters are not considered in any of the academic books. It would be nice if one of the big yeast manufacturers would take this up and give some solid lab results.
• If we are claiming O2 uptake is much higher surface ratios because of the homebrew scale - it feels like this should also be applied to our fermentation transfers. I haven't done the math - don't plan to. I imagine we are getting, generally, adequate oxidation for a medium gravity beer in most cases just by a splashy transfer.
• Compared to when I used to get pretty marginal yeast nearly 20 years ago to today, the bar has moved quite a bit. New processes seem to be yielding a more stable delivery of healthy yeast.
• I am a weirdo that from my mead/wine practices uses GoFerm and rehydrates yeast before pitching - and I get consistent results. I do SnS with liquid yeast pitches and only now use pure O2 if my gravity is above 1.065, and only then a day or two into fermentation to keep things going. I know some dry yeast manufacturers now just recommend pitching dry. I just want to make sure that packet is viable.

I feel like lab results are uneccessary if you have your own results to examine.  After all, that's what matters to me.

[tommymorris]

I think one of the benefits of the Shaken Not Stirred started pitched at high krausen is that the yeast has grabbed all the oxygen it needs at that point. Don’t quote me on this. But, that’s how I remember it.

[Village Taphouse]

I also wonder if any and all LO steps have reduced O2 that the yeast might take up when it's pitched.  IIRC, there is virtually no O2 in the wort while you're boiling and even the LO guys say that a "splashy transfer" (as it was called) is fine so maybe LO steps have no bearing on this.  I need to find a glass 1-gallon jug so I can try an SNS starter.  I know Denny says APPLE JUICE! but my stores do not carry any apple juice in glass containers.  I'll keep looking. 

[tommymorris]

I also wonder if any and all LO steps have reduced O2 that the yeast might take up when it's pitched.  IIRC, there is virtually no O2 in the wort while you're boiling and even the LO guys say that a "splashy transfer" (as it was called) is fine so maybe LO steps have no bearing on this.  I need to find a glass 1-gallon jug so I can try an SNS starter.  I know Denny says APPLE JUICE! but my stores do not carry any apple juice in glass containers.  I'll keep looking.

Grab a gallon of mayonnaise at Costco or Sam’s, eat a bunch of sandwiches, and then your problem will be solved!

Or buy a 1 gallon fermenter off Amazon like I did.

[mchrispen]

Keep in mind that LO folks using metabisulfites must exhaust the sulfite before pitching. In that case we would assume 0 do, and oxygenate until reaching a target PPM measures with a meter. I do this with my LO batches when pitching liquid yeast (SnS).

I have no idea how to orient that target number if using a SnS starter.  Maybe I’m over doing it.


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[lupulus]

Note that Denny is now using SNS starters. That process gives the yeast oxygen before pitching it into the beer. Is it enough oxygen? The inventor of the SNS method says yes, but I am not convinced. I think that some kind of aeration during the transfer from kettle to fermenter is still worthwhile. I have a wine-type aerator that I put on the end of my transfer hose. I no longer use oxygen except for very high gravity beers.

Anybody that knows biochemistry and yeast (and any cell) aerobic metabolism can tell you that there won't be any significant yeast growth if you don't oxygenate at pitching.
If you have enough viable and vital cells at pitching (whatever the method used to produce the cells) to carry the fermentation, then the wort will ferment, if not, it won't ferment completely.

Yeast growth produces secondary flavor compounds, so beer from a fermentation with yeast growth will taste differently from beer produced with no yeast growth.
Better or worse is for the brewer to decide.

Is it enough oxygen?
It depends.
Is NOT enough to produce significant growth during the main fermentation.
It may be enough to produce sufficient cells in your starter depending on many factors including initial count and vitality, nutrients provided and oxygen provided.

Sent from my SM-G981U1 using Tapatalk

[Village Taphouse]

I also wonder if any and all LO steps have reduced O2 that the yeast might take up when it's pitched.  IIRC, there is virtually no O2 in the wort while you're boiling and even the LO guys say that a "splashy transfer" (as it was called) is fine so maybe LO steps have no bearing on this.  I need to find a glass 1-gallon jug so I can try an SNS starter.  I know Denny says APPLE JUICE! but my stores do not carry any apple juice in glass containers.  I'll keep looking.

Grab a gallon of mayonnaise at Costco or Sam’s, eat a bunch of sandwiches, and then your problem will be solved!

Or buy a 1 gallon fermenter off Amazon like I did.

I just found one on Amazon.  SOLD!    There will be an SNS starter made here soon.  I'll have to read up on it again. 

[Village Taphouse]

Note that Denny is now using SNS starters. That process gives the yeast oxygen before pitching it into the beer. Is it enough oxygen? The inventor of the SNS method says yes, but I am not convinced. I think that some kind of aeration during the transfer from kettle to fermenter is still worthwhile. I have a wine-type aerator that I put on the end of my transfer hose. I no longer use oxygen except for very high gravity beers.

Anybody that knows biochemistry and yeast (and any cell) aerobic metabolism can tell you that there won't be any significant yeast growth if you don't oxygenate at pitching.
If you have enough viable and vital cells at pitching (whatever the method used to produce the cells) to carry the fermentation, then the wort will ferment, if not, it won't ferment completely.

Yeast growth produces secondary flavor compounds, so beer from a fermentation with yeast growth will taste differently from beer produced with no yeast growth.
Better or worse is for the brewer to decide.

Is it enough oxygen?
It depends.
Is NOT enough to produce significant growth during the main fermentation.
It may be enough to produce sufficient cells in your starter depending on many factors including initial count and vitality, nutrients provided and oxygen provided.

I have mentioned and requoted your part in bold a few times and I seem to remember someone smarter than me say that yeast growth creates flavors that beer drinkers find pleasing.  The conclusion was that overpitching so that no yeast growth would occur would result in a less-pleasing beer.  I realize I am probably oversimplifying but we have knocked this around before and because of this I have restrained myself on the amount of harvested slurry I pitch on a given batch hoping that I would get some of that pleasing flavor.  Also, I have noticed a few times that the first pitch of a yeast (say, right from the starter) has produced the best beer in the group of batches made with that yeast and that first batch probably had fewer yeast cells then the subsequent batches.  I remember one specifically made with WLP940 Mexican Lager that was absolutely dynamite (first batch from the starter) and the rest of the batches were good but not as good as that one. 

[denny]

I also wonder if any and all LO steps have reduced O2 that the yeast might take up when it's pitched.  IIRC, there is virtually no O2 in the wort while you're boiling and even the LO guys say that a "splashy transfer" (as it was called) is fine so maybe LO steps have no bearing on this.  I need to find a glass 1-gallon jug so I can try an SNS starter.  I know Denny says APPLE JUICE! but my stores do not carry any apple juice in glass containers.  I'll keep looking.

Grab a gallon of mayonnaise at Costco or Sam’s, eat a bunch of sandwiches, and then your problem will be solved!

Or buy a 1 gallon fermenter off Amazon like I did.

I just found one on Amazon.  SOLD!    There will be an SNS starter made here soon.  I'll have to read up on it again.

Male a qt. of 1.035ish wort.  Cool it. Put it in your 1 gal. container.  Shake until container is full of foam (DO NOT use foam control when you make the wort). Pitch your yeast. Cover loosely with foil.  Put it in a room tempish place.

[Village Taphouse]

Male a qt. of 1.035ish wort.  Cool it. Put it in your 1 gal. container.  Shake until container is full of foam (DO NOT use foam control when you make the wort). Pitch your yeast. Cover loosely with foil.  Put it in a room tempish place.

* makes notes *

I plan to do this in about 7-10 days.  Thanks Denny. 

[RC]

Note that Denny is now using SNS starters. That process gives the yeast oxygen before pitching it into the beer. Is it enough oxygen? The inventor of the SNS method says yes, but I am not convinced. I think that some kind of aeration during the transfer from kettle to fermenter is still worthwhile. I have a wine-type aerator that I put on the end of my transfer hose. I no longer use oxygen except for very high gravity beers.

Anybody that knows biochemistry and yeast (and any cell) aerobic metabolism can tell you that there won't be any significant yeast growth if you don't oxygenate at pitching.
If you have enough viable and vital cells at pitching (whatever the method used to produce the cells) to carry the fermentation, then the wort will ferment, if not, it won't ferment completely.

Yeast growth produces secondary flavor compounds, so beer from a fermentation with yeast growth will taste differently from beer produced with no yeast growth.
Better or worse is for the brewer to decide.

Is it enough oxygen?
It depends.
Is NOT enough to produce significant growth during the main fermentation.
It may be enough to produce sufficient cells in your starter depending on many factors including initial count and vitality, nutrients provided and oxygen provided.

Sent from my SM-G981U1 using Tapatalk

If by metabolism you mean respiration, then brewers yeast can't be put in the same category as "any cell". Yeast in beer wort do not use the oxygen for aerobic respiration because of the Crabtree effect. At the sugar concentration found in even weak beer wort, yeast will always use the anaerobic fermentation pathway to multiply, regardless of how much oxygen is present. Oxygenating the wort, whether via splashing or stone, does not necessarily result in more cells, it results in stronger cells that can more easily cross the finish line.