O2 in starter

[Minbari]

Doing an experiment to see if this matters at all. 1098 2 stage starter for a high gravity beer.

Bursting pure o2 into the starter. 1 second every 15 minutes. rate of 0.12 l/min. Have read that there is some evidence that it helps build higher yeast counts.
we shall see, since i don't have a microscope to count them, lol.

 

[Minbari]

I will predicate this statement with the fact that i have no scientific way to measure the health or volume of yeast.

That said, after a two stage 4 day starter, the yeast cake at the bottom, after a 24 cold crash, was easily 2x what it was in previous starters. 1098 was the yeast and after pitching it in the wort at 68F, it had a 6 hour lag time. 48 hours later it has gone from 1.089 to 1.032 and it is still going.

Could I be biased? Sure, but i will continue to execute this experiment for a few more and see if the trend Continues.

 

[Minbari]

Finished active fermentation yesterday. 1.089 to 1.021 in 2 days. Not bad

 

[Ward Chillington]

The herd will love the o2 especially when it's in its initial growth phase but at what point is the introduction a diminished return? Have to read up on that...if you haven't already, go find the Bru Lab episode that covers low gravity starters....Maria Mutsablau .....I butchered her last name there...my recall on that was if you don't have the carbon, ie sugars, in the wort...you need a high dose of nutrients but either way...o2 is a critical part of the mix.
Other than that...it sounds like what you are doing is working!

 

[Minbari]

The herd will love the o2 especially when it's in its initial growth phase but at what point is the introduction a diminished return? Have to read up on that...if you haven't already, go find the Bru Lab episode that covers low gravity starters....Maria Mutsablau .....I butchered her last name there...my recall on that was if you don't have the carbon, ie sugars, in the wort...you need a high dose of nutrients but either way...o2 is a critical part of the mix.
Other than that...it sounds like what you are doing is working!

Looking positive for the first one anyway. Will be doing another higher gravity beer in a couple weeks. So we'll see if that one responds similarly

 

[Bigbre04]

I regularly double batch and treat my first batch as a starter. I always push O2 on the first batch.

For a small starter, i would assume your stir plate would provide plenty of oxygenation for that quantity of yeast without the added infection vector, but I could be wrong.

I just overpitch with dry yeast because i am a simple creature who doesnt have the fucks to reuse yeast and all of the management/planning it requires. PLUS Apex Voss is so fucking cheap. Brewed a coconut brown yesturday. It was already fermenting before i had everything cleaned up. started at 13.7 and its down in the 3s this morning at 38.7C. Tastes amazing.

 

[Minbari]

I regularly double batch and treat my first batch as a starter. I always push O2 on the first batch.

For a small starter, i would assume your stir plate would provide plenty of oxygenation for that quantity of yeast without the added infection vector, but I could be wrong.

I just overpitch with dry yeast because i am a simple creature who doesnt have the fucks to reuse yeast and all of the management/planning it requires. PLUS Apex Voss is so fucking cheap. Brewed a coconut brown yesturday. It was already fermenting before i had everything cleaned up. started at 13.7 and its down in the 3s this morning at 38.7C. Tastes amazing.

I am not using alot of o2. 0.12L/min rate for 1sec every 15 minutes. So this is just supplemental, plus helps to expel co2.

Jury is still out though. Only 1 batch down this way

 

[Bigbre04]

I am not using alot of o2. 0.12L/min rate for 1sec every 15 minutes. So this is just supplemental, plus helps to expel co2.

Jury is still out though. Only 1 batch down this way

I dont really see many negatives to it. I wouldnt assume that it would drive the co2 out though. likely it is just a mix of co2 and o2 above the liquid. CO2 is heavier than air. Its tough to push co2 out the top of something without a high flow rate. Honestly i try to think of "draining" co2 like you would water.

 

[HighVoltageMan!]

One downside is that when the yeast are near terminal gravity, oxygen should not be present in the starter. Oxygen causes the yeast to use up it glycogen reserves needed for the next fermentation. This is true also when yeast is stored, there should be little or no oxygen to keep the yeast viable for a longer period.

I give the yeast a two minute burst of oxygen at the beginning of the starter, afterward I just use a stir bar to agitate the starter. There is a small amount of oxygen being introduced by the agitation along with dissipation of co2 in solution. As the starter get closer to terminal gravity, I stop stirring. I then crash the starter. I don’t have an accurate method to determine when it’s near terminal gravity, so I watch the krausen. When it starts to fall I know I’m past the majority of yeast growth and carbon source for the yeast.

Since using this method my lag times on my beers are down by at least 30-40% with the same amount or slightly less yeast. I now have 14-16 hour lag on lagers pitch at 48F. I think this is because the yeast still have a lot of reserves and are still in a fairly high metabolic state because the starter never hit terminal gravity.

Nice experiment, it’s good you shared your work. Thank you!

 

[Minbari]

One downside is that when the yeast are near terminal gravity, oxygen should not be present in the starter. Oxygen causes the yeast to use up it glycogen reserves needed for the next fermentation. This is true also when yeast is stored, there should be little or no oxygen to keep the yeast viable for a longer period.

I give the yeast a two minute burst of oxygen at the beginning of the starter, afterward I just use a stir bar to agitate the starter. There is a small amount of oxygen being introduced by the agitation along with dissipation of co2 in solution. As the starter get closer to terminal gravity, I stop stirring. I then crash the starter. I don’t have an accurate method to determine when it’s near terminal gravity, so I watch the krausen. When it starts to fall I know I’m past the majority of yeast growth and carbon source for the yeast.

Since using this method my lag times on my beers are down by at least 30-40% with the same amount or slightly less yeast. I now have 14-16 hour lag on lagers pitch at 48F. I think this is because the yeast still have a lot of reserves and are still in a fairly high metabolic state because the starter never hit terminal gravity.

Nice experiment, it’s good you shared your work. Thank you!

I did turn o2 off after 30 of 48 hour process. So maybe it worked out. Gonna give it few more batches to make a final opinion

 

[Minbari]

Next batch, done the same way. Pure o2 burst at 15 min intervals for 1 sec for the first 24 hours. Did 2 stages of 1214 for a Belgian dark strong ale.

As you can see, 4 1/2 days and it is done! Lag time was 7.5 hours! The extra bump at day 3 was the 2.75 pound of candi sugar added.

 

[Ward Chillington]

@Minbari ....what's the yellow line?

 

[Minbari]

@Minbari ....what's the yellow line?

the one at the top? that is the predicted OG

line at the bottom is the FG, the one just above it is the predicted FG before the sugar