Does anyone add more air or pure O2 while creating a starter

[h22lude]

I'm just curious if people aerate the wort, pitch and then let the yeast do their thing or does anyone add more O2 either with pure O2 or more air while the starter is going.

I know with a starter to use foil but not much air gets in with the foil so once the yeast use the O2 in the head space, not much more is introduced. May not be a big deal with fresh yeast but would it be good to hit the head space with some pure O2 maybe 12 hours after pitching just to give the yeast a little more.

 

[day_trippr]

I believe that as long as the vessel isn't air tight if yeast are consuming oxygen it will be replenished.
That said, I always hit my starters with pure O2 immediately after pitching.
And if I'm doing a large (5 liter) starter I'll hit it again 6 hours after the first shot...

Cheers!

 

[tgolanos]

My starter habbit is any time I walk into the kitchen, I shake the crap out of the starter to feed it oxygen. Once it begins to form a kräusen, I leave it alone, though. Works pretty well thus far.

 

[eadavis80]

I use a foam stopper so I THINK air gets through that way. Anyway, I just shake it every time I enter the room and I've never had an issue. Never thought about using an aeration system for a starter. I've never found it even close to necessary.

 

[h22lude]

I believe that as long as the vessel isn't air tight if yeast are consuming oxygen it will be replenished.
That said, I always hit my starters with pure O2 immediately after pitching.
And if I'm doing a large (5 liter) starter I'll hit it again 6 hours after the first shot...

Cheers!

I figured that too but read this last night. https://www.homebrewersassociation.org/forum/index.php?topic=11697.0

It sounds to me like Martin is saying even with foil or foam, not enough oxygen can get into the flask.

 

[helibrewer]

Yes, pure O2 and zinc, then again when I pitch the wort

 

[mabrungard]

As I mention in that other thread, yeast is evolving CO2 and its hard to expect that there will be enough exchange with the atmosphere to replenish the O2. Pumping filtered air into the starter vessel headspace should assure that there is enough O2 for yeast synthesis.

 

[h22lude]

As I mention in that other thread, yeast is evolving CO2 and its hard to expect that there will be enough exchange with the atmosphere to replenish the O2. Pumping filtered air into the starter vessel headspace should assure that there is enough O2 for yeast synthesis.

Do you continuously pump air in or add new air couple times during the day?

 

[triethylborane]

I pitch and let the stir plate do the work.

 

[TheHopfather]

Isn't that the idea behind the stir plate? I thought the whirlpool caused greater air exchange somehow?

 

[h22lude]

Isn't that the idea behind the stir plate? I thought the whirlpool caused greater air exchange somehow?

It does if there is enough O2. What Martin is saying is once the O2 in the headspace is used up, not enough more O2 comes into the flask.

 

[MaxStout]

I pump O2 into the starter for several seconds, put a foam stopper on the flask and run it on the stir plate. I figure that puts enough O2 inside the flask to give the yeast a good head start.

 

[triethylborane]

It does if there is enough O2. What Martin is saying is once the O2 in the headspace is used up, not enough more O2 comes into the flask.

Lol, is this guy brewing at 35,000ft ASL or hermetically sealing his flask?

 

[day_trippr]

Seems like the Gas Laws aren't getting respect...

Cheers!.

 

[h22lude]

Seems like the Gas Laws aren't getting respect...

Cheers!.

Can't tell if this is for me or for Tri lol

 

[triethylborane]

Can't tell if this is for me or for Tri lol

Its what I was hinting at. Foam stoppers and aluminum foil hats aren't going to prevent O2 from entering the flask (stir plate or not).

 

[GoeHaarden]

Its what I was hinting at. Foam stoppers and aluminum foil hats aren't going to prevent O2 from entering the flask (stir plate or not).

With agitation or stir plate, there is going to be gas exchange in an open system. Right?

@h22lude - off topic, but I wanted to give a shout out, because I had an '01 Lude many years ago. Fun little car after some tuning...

 

[h22lude]

Its what I was hinting at. Foam stoppers and aluminum foil hats aren't going to prevent O2 from entering the flask (stir plate or not).

But what I think Martin is saying is with such a small opening in a flask and 99% of that opening being covered with foil, there isn't enough exchange. Most of the headspace in the flask will be co2 from the yeast. Martin isn't saying no O2 is getting in. He is saying not enough is getting in.

 

[h22lude]

With agitation or stir plate, there is going to be gas exchange in an open system. Right?

@h22lude - off topic, but I wanted to give a shout out, because I had an '01 Lude many years ago. Fun little car after some tuning...

Right but how much is really the question. This is open but how open is it really? The opening of a flask is an inch or two. Then we put foil to cover most of that opening. With the yeast expelling co2, how much extra O2 is getting into the flask? Im not a chemist so I don't know but Martin is saying not enough O2 can get in with these types of flasks. Maybe if we did a starter in a big open bowl.

Loved my prelude. I see one once in a while and wish I still had it.

 

[BrewKnob]

I do a 10 gallon batch with extract and split. Pitch 2 different yeasts and plan 6 matches, 3 from each yeast, accordingly.

I aerate each with pure O2 and a stainless airstone.

 

[BrewKnob]

Yeast need O2 only at the beginning of the ferment...after that it is not good to introduce O2.

 

[h22lude]

Yeast need O2 only at the beginning of the ferment...after that it is not good to introduce O2.

This is true for beer not for a starter. Yeast need O2 throughout the entire starter.

 

[IslandLizard]

I've added pure O2 through a 0.5 micron stone to my starter wort, right after pitching the yeast and a good thorough shake.

I used a low O2 flow (1/32 l/m) for 3-4 minutes. Then let it stand for an hour before putting on an orbital shaker. I think the agitation drives off the excess O2 rather quickly, but leaves the headspace O2 rich at least for some time. I can't say the starters produced more or better yeast or any quicker than without the O2 addition.

Now I can see producing a quick vitality starter using a few pure O2 injections over a few hours. The Shaken not Stirred method may benefit from a pure O2 injection too.

 

[rhys333]

My starter habbit is any time I walk into the kitchen, I shake the crap out of the starter to feed it oxygen. Once it begins to form a kräusen, I leave it alone, though. Works pretty well thus far.

I do the same as you and it works great. I consider this the "no shake" method, and will do this when I'm short on time. I treat it like a mini beer and add the whole thing to the main batch. When I'm able to make my starter a few days ahead, I'll continue shaking even after high krausen, decanting the oxidized beer before pitching.

On average, main batch fermentation picks up in 8 hours. I haven't seen a need for extra O2.

 

[tgolanos]

On average, main batch fermentation picks up in 8 hours. I haven't seen a need for extra O2.

I average about 12 hours from pitch to kräusen in winter. In warmer weather, it's about 8 hours as well.