Adding oxygen to yeast starters?

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Nate R

Nate R

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Anybody ever add oxygen to their yeast starters? I know it makes a HUGE difference in turning wort into beer.
Does it make a difference on a yeast starter with a stir plate?

Assuming all best practices for cleaning, sanitizing, etc are followed, will it make a noticeable difference?

My plan is to use a diffusion stone with my food grade oxygen tank. I have more oxygen in there than i can use in a lifetime, so why not? Any potential pitfalls? All i can think of is perhaps more chances of an infection- i.e. more varibles introduced to the process.

I searched titles for this thread and could not find any, so forgive me if this covered somewhere else.

Thanks all!
 
i've read that most people say to leave the flask unsealed....so if anything having positive pressure of O2 would reduce infection risk? i don't make starters just repitch, so i'm just guessing....
 
Jag75 said:
I use a foam thingamajig in the top .
Click to expand...


i could use a thingamajig too.....got a link? not for a starter but catching evaporating water.....

edit: lol, unless you just mean a sponge...;) (hmmm, now that i think about it, that might help too.....
 
damn it....

"Autoclavable up to 249°F (121°C). " i'd need something rated to 260f-270f........i'll look into lab stuff though, good idea!

edit: sorry for hijacking, i swear i'm not a pirate! :mug:
 
I do starters on a stir plate, with a stopper with two holes. One has an airlock, for outgoing gasses, and the other has sterile filtered air, not O2, pumped into the headspace. This keeps a constant supply of oxygen going in while propagating. If all you rely on is the headspace oxygen and whatever minimal gas transfer you'll get through foil or foam, well the yeast will consume that oxygen pretty quickly and then your stir plate doesn't do much.
 
Oxygen is the key ingredient that yeast use for turning glucose into biomass so it's 100% necessary in a starter, otherwise you're just fermenting a 1-2liter batch of unhopped beer

Fermentation is a different process than growth.. Different metabolic pathways, different mechanisms. If you want alcohol, apply initial oxygen to boost initial growth, then deprive the yeast of oxygen to force them to use up the sugar in their anaerobic pathway.

If you want growth then keep the gravity (and therefore alcohol low) and keep oxygen in there.

FWIW I had a pro brewer friend leave his oxygen wand in a starter bubbling, instead of stirring, and then did a cell count at the end and found that he had 3x more cells than predicted for the starter size. He just did it for giggles and curiosity, not in practice
 
I've been doing continuously aerated starters for several years now and I've never had fermentations go so well, compared to a simple stirred starters.
What I do is I place a 2 micron stone in the flask and connect a powerful pump (60 l/min) with sterile filter to it and keep it running all the time until the starter is done. Incidentally this provides sufficient agitation that a stir plate is no longer necessary. An antifoam agent on the other hand is very much needed if you don't want half the yeast to end up on the floor. Ask me how I know... 🤕

Personally I wouldn't do it with pure oxygen since worst case such high concentrations of O2 can be detrimental or even toxic to yeast, best case you would get the same improvement by pumping sterile air without using up a ton of O2.

The important thing here is to get the oxygen (whether pure or mixed with N2) in the liquid continuously and efficiently. If you jus push O2 in the headspace you'll still be relying on diffusion to actually get the O2 in solution and diffusion is way too slow to work efficiently on the timescale we're talking here (normally, 24 to 36 hours). The only way to do that is to forcibly push the gas through the liquid through an aeration stone, much like we do with wort, but in this case continuously.
 
I was addressing subsequent posts advocating just aerating the headspace, to jus the OP.
 
as far as a filter goes....don't yeast like sorta swim to surface for a breath? no expert, but they like have 'fins/tails' and swim around?
 
TheMadKing said:
Oxygen is the key ingredient that yeast use for turning glucose into biomass so it's 100% necessary in a starter, otherwise you're just fermenting a 1-2liter batch of unhopped beer

Fermentation is a different process than growth.. Different metabolic pathways, different mechanisms. If you want alcohol, apply initial oxygen to boost initial growth, then deprive the yeast of oxygen to force them to use up the sugar in their anaerobic pathway.

If you want growth then keep the gravity (and therefore alcohol low) and keep oxygen in there.

FWIW I had a pro brewer friend leave his oxygen wand in a starter bubbling, instead of stirring, and then did a cell count at the end and found that he had 3x more cells than predicted for the starter size. He just did it for giggles and curiosity, not in practice
Click to expand...

^^^^exactly

1.020~1.030 max starter wort, slowly oxygenate while gently swirling the flask to encourage dissolved 02 in the wort. Foam stopper and low speed on the stir plate. As Nate said, not too much oxygen since you want anaerobic growth in the starter. Once the yeasties build up their numbers, there'll be a hungry bunch ready to attack the sugar-rich wort in the fermenter.

Brooo Brother
 
I think I've learned something here about my starter process, so appreciate the knowledge. I'm wondering what the rest of your process is after letting the yeast grow: do you just pitch when the starter has reached its peak, or do you refrigerate and decant? I've been doing the latter, refrigerating for 24/36 hours, then taking the flask out and letting it get to room temp, decanting, then pitching. What's best?
 
mcmichaelangelo said:
I think I've learned something here about my starter process, so appreciate the knowledge. I'm wondering what the rest of your process is after letting the yeast grow: do you just pitch when the starter has reached its peak, or do you refrigerate and decant? I've been doing the latter, refrigerating for 24/36 hours, then taking the flask out and letting it get to room temp, decanting, then pitching. What's best?
Click to expand...

Both work fairly equally well

The downside to pitching the full starter is that you risk off flavors from the oxidized starter wort

The downside to pitching refrigerated slurry is that it takes longer to produce, and arguably has less active cells
 
TheMadKing said:
Both work fairly equally well

The downside to pitching the full starter is that you risk off flavors from the oxidized starter wort

The downside to pitching refrigerated slurry is that it takes longer to produce, and arguably has less active cells
Click to expand...
Thanks, that's my understanding. I'm guessing that the "less active cells" part of the slurry approach might be offset by adding the oxygenation process to the starter build.
 
mcmichaelangelo said:
Thanks, that's my understanding. I'm guessing that the "less active cells" part of the slurry approach might be offset by adding the oxygenation process to the starter build.
Click to expand...

Partly, but it's also offset by oxygenation of your wort at pitch time, which is ideal no matter how you pitch
 
TheMadKing said:
Partly, but it's also offset by oxygenation of your wort at pitch time, which is ideal no matter how you pitch
Click to expand...
Thanks. I've been oxygenating the wort in-line on its way from BK to fermenter, but I've always been irritated by the wort leaking out of the o2 stone barb into the o2 line after I shut off the o2. I'm wondering if oxygenating in the fermenter (once all the wort's in) would be as effective, thus eliminating the hassle of having oxygenation as part of the transfer process...
 
Vale71 said:
I've been doing continuously aerated starters for several years now and I've never had fermentations go so well, compared to a simple stirred starters.
What I do is I place a 2 micron stone in the flask and connect a powerful pump (60 l/min) with sterile filter to it and keep it running all the time until the starter is done. Incidentally this provides sufficient agitation that a stir plate is no longer necessary. An antifoam agent on the other hand is very much needed if you don't want half the yeast to end up on the floor. Ask me how I know... 🤕

Personally I wouldn't do it with pure oxygen since worst case such high concentrations of O2 can be detrimental or even toxic to yeast, best case you would get the same improvement by pumping sterile air without using up a ton of O2.

The important thing here is to get the oxygen (whether pure or mixed with N2) in the liquid continuously and efficiently. If you jus push O2 in the headspace you'll still be relying on diffusion to actually get the O2 in solution and diffusion is way too slow to work efficiently on the timescale we're talking here (normally, 24 to 36 hours). The only way to do that is to forcibly push the gas through the liquid through an aeration stone, much like we do with wort, but in this case continuously.
Click to expand...

Got you on the anti-foam agent, for sure!
A few follow-up questions if I may:

#1: When you say sterile filter, is it like the "in-line" filter I referenced above in post #9? If not, what do you use?

#2: You say powerful pump- 60L/Minute? Got any links or reference? Are we talking an aquarium pump?

#3: I assume you still use an Erlenmeyer flask? If not, what type vessel? Now, how do you keep the vessel sealed with all the air going in? Special two-hole stopper, or just foil over the lid, and the tube goes in, air come out?

#4: Using your method above, do you see any potential benefit to still having it on the stir plate? Or, say- 24 hours with the pump, then 24 hours on the stir plate? Or- no stir plate at all?

Thanks for the thoughts!
 
Nate R said:
Got you on the anti-foam agent, for sure!
A few follow-up questions if I may:

#1: When you say sterile filter, is it like the "in-line" filter I referenced above in post #9? If not, what do you use?

#2: You say powerful pump- 60L/Minute? Got any links or reference? Are we talking an aquarium pump?

#3: I assume you still use an Erlenmeyer flask? If not, what type vessel? Now, how do you keep the vessel sealed with all the air going in? Special two-hole stopper, or just foil over the lid, and the tube goes in, air come out?

#4: Using your method above, do you see any potential benefit to still having it on the stir plate? Or, say- 24 hours with the pump, then 24 hours on the stir plate? Or- no stir plate at all?

Thanks for the thoughts!
Click to expand...

1#: Yes!

2#: https://www.amazon.com/VIVOSUN-Comm...pqg&hsa_cr_id=9152538390001&ref_=sb_s_sparkle

3#: Erlenmeyer with foil on top.

4#: No stir plate at all up to 4 liters as you already get plenty of agitation from the air stone.
 
Nate R said:
Thanks fot the quick responses!
Lost one- you say UP TO 4L. Is this because the flask needs extra headspace/room with the agistation? In other words you cannot do 5L?
Click to expand...
That is correct. Even with antifoam you cannot fill the flask to nominal capacity or some foam will overflow and you'll have a mess on your hands.
 
Thanks for the replies all.
I am doing a 5L White Labs 'Mexican Lager' starter. (gonna try making an easy sippin' summer drinkin' beer!)
Anyways... I had a pack that was "still good" but I made a 1L step-up with it.
I just pitched that into 5L.
I added a blast of pure Oxygen to it right before I pitched. (Appx. 2 liters/Minute flow for about 45 seconds, while it was stirring)

I am looking to get a few opinions from y'all...

#1 (This is un-related to the adding Oxygen question). Would there be any reasoning behind the large the starter, the longer amount of time left on the stir plate?? In other words, does a 1L starter "finish" faster than a 2L starter? What about a 5L starter?

#2: Would there be any potential benefit from hitting with some more Oxygen in a little while? And if so, what would the timing be? Say, 4, 6, 8, or 12 hours later? 24 hours later? Finally- if there is a benefit, how many more times? Once more blast, twice more, etc.?

Thanks all!
 
Nate R said:
In other words, does a 1L starter "finish" faster than a 2L starter? What about a 5L starter?
Click to expand...

Given the same amount of yeast pitched into each starter, yes, smaller starters finish faster than larger starters.
 
VikeMan said:
Given the same amount of yeast pitched into each starter, yes, smaller starters finish faster than larger starters.
Click to expand...
And given the same amount of yeast, smaller starters will end with smaller cell counts.

its a trade off.
 
Well, fwiw... i'm doing an experiment of sorts. No, thats not right. I'm just trying a new method.
Did a 5L starter from my 1L step up. Hit it with the O2 for a bit. (As mentioned above).
Hit it again 6 hours later with a shorter blast of O2.
Also, i usually run these for 48 hours. I am thinking i will run it for 60 hours or so- really let thoose little guys get to work.
Any potential issues with this?

Also- note- if you try this, you gotta hit the flask with one more drop of fermcap! Holy cow!
 
Nate R said:
Well, fwiw... i'm doing an experiment of sorts. No, thats not right. I'm just trying a new method.
Did a 5L starter from my 1L step up. Hit it with the O2 for a bit. (As mentioned above).
Hit it again 6 hours later with a shorter blast of O2.
Also, i usually run these for 48 hours. I am thinking i will run it for 60 hours or so- really let thoose little guys get to work.
Any potential issues with this?

Also- note- if you try this, you gotta hit the flask with one more drop of fermcap! Holy cow!
Click to expand...

Going 60 hours on a stir plate sure does seem to be awfully long.... Maybe I'm wrong, but I would think the starter, even that size, would be past its peak and those little guys would be fermenting rather than multiplying for growth, no?
 
CodeSection said:
Going 60 hours on a stir plate sure does seem to be awfully long.... Maybe I'm wrong, but I would think the starter, even that size, would be past its peak and those little guys would be fermenting rather than multiplying for growth, no?
Click to expand...
Yeah... i dunno. All the "literature" says 48 hours. A lot of posts I read here say 24 hours is fine. Sp maybe 48 hours is pushing it too far? I have hit it with a third blast of Oxygen this morning (so, 3 blasts so far: At starting, at 6 hours, and at 16 hours). I think I will crash it at 48 hours. No need to push it that far I guess.
 
You seem to suffer from the delusion that you can somehow control when the yeast will stop working... :p

Seriously, at 60 hrs it will be long finished unless it was some old, half-dead yeast. Giving it more oxygen so late is not a good idea as it might stimulate metabolism and cause it to deplete its glycogen reserves, which will be much needed come pitching time.
 
Vale71 said:
You seem to suffer from the delusion that you can somehow control when the yeast will stop working... :p

Seriously, at 60 hrs it will be long finished unless it was some old, half-dead yeast. Giving it more oxygen so late is not a good idea as it might stimulate metabolism and cause it to deplete its glycogen reserves, which will be much needed come pitching time.
Click to expand...
Well, that and so many, many, many other delusions!
Ok, so no more Oxygen blasts. Done.
I will pull this thing at 48 hours then. That will give it another 32 hours or so of time to spin on the stir plate. No more oxygen blasts.
Thoughts?
 
Nate R said:
Well, that and so many, many, many other delusions!
Ok, so no more Oxygen blasts. Done.
I will pull this thing at 48 hours then. That will give it another 32 hours or so of time to spin on the stir plate. No more oxygen blasts.
Thoughts?
Click to expand...

If the whole point of adding the O2 was to stimulate growth, then why is there a need to stir for 48 hours? If you have concerns, can't you turn off the stir plate and let it settle to see how it is building up?

When I made a starter with Wyeast 1214, I thought it took a long time to build up so it remained on the stir plate for about 48 hours. The yeast wasn't old and I never experienced a starter taking that long. Later after reading different threads, WY 1214 is slow to start.

I thought maybe it was my stir plate as I thought it was struggling. I found out later MB reclassified the starter size it could handle. My Maelstrom I bought earlier in the year is a monster!

FWIW, 48 hours, especially after your three O2 additions seems long too....
 
CodeSection said:
If the whole point of adding the O2 was to stimulate growth, then why is there a need to stir for 48 hours? If you have concerns, can't you turn off the stir plate and let it settle to see how it is building up?

When I made a starter with Wyeast 1214, I thought it took a long time to build up so it remained on the stir plate for about 48 hours. The yeast wasn't old and I never experienced a starter taking that long. Later after reading different threads, WY 1214 is slow to start.

I thought maybe it was my stir plate as I thought it was struggling. I found out later MB reclassified the starter size it could handle. My Maelstrom I bought earlier in the year is a monster!

FWIW, 48 hours, especially after your three O2 additions seems long too....
Click to expand...
Ahh... I think I see your point- so, one should EITHER: Add Oxygen OR stir for 48 hours?
 
Nate R said:
Ahh... I think I see your point- so, one should EITHER: Add Oxygen OR stir for 48 hours?
Click to expand...

I read your new process and it seems to conflict with your previous process. My point in bringing up my experience with WY 1214 was that I learned it was a slow starter. I had not gone 48 hours on a stir plate before.

Typically, depending when I first start the starter and my work schedule, it is on the stir plate between 24-36 hours. Somewhere in between.... Again, as mentioned in the previous post, I stop the stir plate from spinning and let it settle to see how the starter has built up before deciding to pour off the overbuilt starter and putting both in the refrigerator. YMMV
 
Nate R said:
Anybody ever add oxygen to their yeast starters? I know it makes a HUGE difference in turning wort into beer.
Does it make a difference on a yeast starter with a stir plate?

Assuming all best practices for cleaning, sanitizing, etc are followed, will it make a noticeable difference?

My plan is to use a diffusion stone with my food grade oxygen tank. I have more oxygen in there than i can use in a lifetime, so why not? Any potential pitfalls? All i can think of is perhaps more chances of an infection- i.e. more varibles introduced to the process.

I searched titles for this thread and could not find any, so forgive me if this covered somewhere else.

Thanks all!
Click to expand...

There is nothing wrong with adding more oxygen but you already have quite a bit of air (nitrogen, oxigen, co2) into your started by using the stir plate.
You are totally overthinking it, tell me you are not a js programmer :).


Based on experience even a starter is not needed in the homebrew setup as long as you have a healty and eager pitching yeast. yeah, yeah, I am going to hear the world of it by saying that. My take is focus on water profile, proper yeast and temps(mash in, out, fermentation. The rest really won't make much of a significant difference.
 
theQ said:
There is nothing wrong with adding more oxygen but you already have quite a bit of air (nitrogen, oxigen, co2) into your started by using the stir plate.
You are totally overthinking it, tell me you are not a js programmer :).


Based on experience even a starter is not needed in the homebrew setup as long as you have a healty and eager pitching yeast. yeah, yeah, I am going to hear the world of it by saying that. My take is focus on water profile, proper yeast and temps(mash in, out, fermentation. The rest really won't make much of a significant difference.
Click to expand...
I have NO idea what 'js' is... so, no. Not that.

Thanks for the opinions.
And yeah, that's a can o' worms you opened up there!! Lol
 
I had some three year old dry yeast (Bry-97) that I was able to revive. I didn't do the continuous oxygen like some of you all are mentioning here. I just hit the starter with o2 for about 60-90 seconds, pitched the yeast, and put on a stir plate for a few days. Had a nice krausen on it by day 3. Like Nate R mentioned, 'oxygen does make a huge difference in turning wort to beer' and that was the approached I had went with. The beer, IPA, turned out pretty good.

With the last two batches, I collected about 1.5-2L of wort from the tun and pitch my (dry) yeast while the wort was heating to a boil in the kettle. By the end of the day, and the wort had chilled down, I'd pitched the starter and seen activity in as little as 5-6hrs. I wonder if hitting the starter with oxygen would reduce that time even further.
 

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