oxygenating a starter

paulbern

paulbern

Member
Premium Member
Established Member
Joined
Feb 25, 2019
Messages
21
Reaction score
53
Points
13
Hi Gang,

I'll be making a starter for a Kolsch using WLP029. I don't have a stir plate, so I was thinking of oxygenating the starter wort like I would for the full batch. Would this help, hurt, or do nothing? The calculator shows a definite improvement using a stir plate over shaking, so I thought oxygenating might achieve similar results.
 
Yes, oxygen would help.

If you don’t have a stir plate, you can make your starter 6-8 hours before pitch. You can use the SNS method, shaken not stirred. Denny Conn is an advocate of it and it does work. The idea is to shake the starter now and then to introduce some oxygen. You would pitch the entire starter at high krausen. This can also be done with a stir plate. Pitching at high krausen allows for a lower pitch rate and works well for ales.

The problem with SNS comes with lagers. You basically need a large biomass and pitching at high krausen brings a number of problems with it. Mostly pitch a warm, ester bomb into cold wort. It’s better to build up the yeast population (biomass), decant and then pitch at the same temperature as the wort. With ales and even a Kolsch, the SNS method would work.
 
phbern said:
Hi Gang,

I'll be making a starter for a Kolsch using WLP029. I don't have a stir plate, so I was thinking of oxygenating the starter wort like I would for the full batch. Would this help, hurt, or do nothing? The calculator shows a definite improvement using a stir plate over shaking, so I thought oxygenating might achieve similar results.
Click to expand...
Won't hurt. Might help generate a few more cells. Give it a try.
 
I'm going a step further to say it WILL help.....simular results? Hmmmmm...gotta microscope?

While I have only the basis of recently hearing it from good sources, Masters Brewer's Podcast #72 with Graham Stewart and the afore mentioned Denny Conn, the added oxygen is helping to build the biomass of yeast you want in the starter...remember you are making as starter not beer so the oxygen at this point is good.

https://www.masterbrewerspodcast.com/072

Worth a listen...maybe a few times, Graham's got quite an accent! Sorry but I don't recall which of the Experimental Brewings it was but since I'm still under #40, I'm guessing it's in the 20 or 30s where Denny covers the SNS method. One of the Beer School segments on the You Tube Craft Brew Channel covers yeast production that further describes oxygen introduction into the process.

Again, I don't have personal experience here but this is how the puzzle pieces went together for me. Please let us know how it comes together for you bern.
 
Ward Chillington said:
I'm going a step further to say it WILL help.....simular results? Hmmmmm...gotta microscope?

While I have only the basis of recently hearing it from good sources, Masters Brewer's Podcast #72 with Graham Stewart and the afore mentioned Denny Conn, the added oxygen is helping to build the biomass of yeast you want in the starter...remember you are making as starter not beer so the oxygen at this point is good.

https://www.masterbrewerspodcast.com/072

Worth a listen...maybe a few times, Graham's got quite an accent! Sorry but I don't recall which of the Experimental Brewings it was but since I'm still under #40, I'm guessing it's in the 20 or 30s where Denny covers the SNS method. One of the Beer School segments on the You Tube Craft Brew Channel covers yeast production that further describes oxygen introduction into the process.

Again, I don't have personal experience here but this is how the puzzle pieces went together for me. Please let us know how it comes together for you bern.
Click to expand...
I do have a microscope. Might at some point do the test, if I had a second stir plate....
 
I certainly think biomass or yeast count is very important. I personally estimate cell count with nearly every and so does most of the professional world of brewing.

That being said, yeast count is only part of the picture. Vitality plays a huge role in a healthy fermentation. The higher the vitality, the lower the cell count needed to get a great beer. So to a point, the SNS method does work if pitched at high krausen and by their own admission it has a lower cell count/biomass. So what's needed is a good pitch of young, vibrant yeast cells. If your yeast is older, more cells are needed. If your yeast is very young, a lower pitch will work just as well. I like a proper pitch with young cells and I use a stir plate for nearly every beer.

The biggest problem with counting yeast with a hemocytometer and a microscope is that you don't know if your cells are young heathy or if your cells have one foot in the grave. That's always been a problem with simple microscope yeast counts, you can't measure vitality with a scope.

As I said previously, it all depends on the situation whether or SNS will work or not. I have used a version of it on ales and it does work, I never would use that method on a lager..
 
HighVoltageMan! said:
New I certainly think biomass or yeast count is very important. I personally estimate cell count with nearly every and so does most of the professional world of brewing.
Click to expand...

Hence my hunch that I typically over pitch a little every time I brew. I am usually using 1 to 2 month old yeast or slurry that I bump up on the stir plate. Granted, I not a lager brewer so I have nothing to advise on that but I also haven't blown a batch of ale using this method. Indeed, cell count is very important.
 
Great news Paul! What was the age on the yeast?
 
If I remember correctly, it was packaged in November. I got that from the website, looking up the lot number. I think it actually said something "entered into QC".
 
phbern said:
If I remember correctly, it was packaged in November. I got that from the website, looking up the lot number. I think it actually said something "entered into QC".
Click to expand...
I

Ok, so not past expiration but maybe in the not enough of a viable count range, never the less, you got beer! If you're into a post op exercise to see if you needed to build up the count, spend a little time with the pitch calculator tool on the site here...ya know..for science! *

*that expression never gets old for me!
 
Sunfire96 said:
That qas an interesting read. I wish he had given step by step instructions. Guess I'll need to dig around on the AHA forum
Click to expand...

I know I've seen it somewhere but basically you make a normal starter in a gallon size jug. Shake the heck out of it to introduce as much O2 as possible. Then pitch your yeast and cover the mouth with loose sanitized foil. Every time you walk past the jug, give it a swirl.

Many of the disadvantages Denny lists about the use of stir plates are not really tied to stir plates. Such as a jug being a better vessel for starters than a flask and letting the yeast go dormant before pitching, aren't stir plate procedures. You can use a jug on a stir plate as easliy as a flask and you take the starter off the stir plate at high kreuzen as easily as lifting it off the counter. So I normally use a gallon jug on a stir plate and pitch shortly after high kreuzen (if the wort is ready that is).

However, cell wall stress from the rotating stir bar does make sense so if it looks like the starter is getting thick with yeast I'll take the starter off the stir plate (maybe after 12-ish hours) and switch to swirling it until pitching. But I don't think it would damage enough yeast cells to cause a haze.
 
A mixed approach to building a starter - interesting.
More timely info, as I spun up a starter this morning. This afternoon, Krauzen was forming, and it spun some more.
Based on what I am reading posted above, I have turned off my stir plate. My starter flask is exhibiting strong fermentation activity. I will use the SNS method, see what happens.
 
Ward Chillington said:
Speaking of Science

https://www.experimentalbrew.com/blogs/saccharomyces/shaken-not-stirred-stir-plate-myth-buster

Cell wall stress...I wonder if that's where my haze is coming from?
Click to expand...
This is a problem if you run the yeast through or harvest from a commercial centrifuge you can get yeast shear. Excessive protein loss from yeast shear can happen and these proteins go into solution and do not drop out. This is very unlikely to happen with a simple starter with a small stir bar, there is simple not enough physical forces in play to cause yeast shear.

The SNS proponents often exaggerate shear and yeast stress. A starter on a stir plate work very well if performed correctly. Labs in breweries use stir plates along with an rotatory stirrers to build up yeast counts. The problem begin when the yeast is left on the stir plate for days. The paper argues that it doesn't aerate the yeast on a stir plate and then argues that when the wort is depleted the yeast starve and can not go into a dormant state, which happens because of the presence of oxygen. You can't have it both ways.

These arguments are partially true. If you leave yeast on the plate for too long, the yeast run out of food. When yeast are nearly out of food they prepare for a period with no food. They build up nutrient reserves, among the nutrients is glycine. If there is oxygen present, the yeast will use up any glycine reserves to prepare for growth, eventually the cells die off. Leaving a stir plate run too long puts the yeast into this condition, this also takes place during long storage of yeast. The longest any starter should stay on a stirrer is @ 24 hours. Some have said 12 hours with the stirrer going and 12 with it off to allow the yeast to build up reserves. I personally like to remove the yeast from the stir plate when there is still some sugar left. Most of the growth takes place in the first 12 hours of being on a stir plate. I think the constant stirrer causes the CO2 levels to be much lower, this is well known to increase yeast growth.

There is no doubt magnetic stirrers build biomass. It is also likely that they can hit maximum cell density better than SNS. SNS does not build biomass as much as a stir plate, but often that is not always needed. Bottom line is stir plates work very well if done correctly. It been use for decades and will continue to be used with great success.
 
I appreciate the insight HVM, thanks! I think what I'm gonna try is oxygenating my starter wort since I have a stone then slow down the plate so I don't have such a vortex and see how that does.
 
Last edited:
Good info. I have used a stir plate for starters for years. Seems to work. Between 100% oxygen and healthy yeast. Lag phase is minimized and possibility of wild yeast or infection is reduced
 
Minbari said:
Good info. I have used a stir plate for starters for years. Seems to work. Between 100% oxygen and healthy yeast. Lag phase is minimized and possibility of wild yeast or infection is reduced
Click to expand...
Ditto. It works so well I have no reason to consider another approach other than using dried yeast when possible.
 
You must log in or register to reply here.
Copyright © 2007-2024 Brewer's Friend, Inc. - Send Feedback - Terms - RSS Feed - Do Not Sell or Share My Personal Information

Back
Top