Increasing Cell Counts in Starters

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permo

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I just wanted to share what i have recently learned. I used to make my starters and just leave them sit until they were done. I would add nutrient to the boil of the wort and aerate..then pitch and forget about it.

To experiement, this week i have two big starters going and about 15 times a day I have been taking the airlocks off of the starters and vigoursly shaking and aerating the wort.

If I had to take a guess, I would say, that visually it appears as if I have at least 4 times the yeast as I normally would have if I simply would have left it alone.

I am sure there is oxidation in the wort, so I am sure to dicant and just pitch slurry, but wow does shaking and aerating constantly increase cell count....from what I can see.
 
Yeah, I think that's why people put them on stir plates. If you're like me and don't have one, shake n bake is the way to go. Doing the same thing while culturing commercial yeasts.
 
Ouroboros said:
Yeah, I think that's why people put them on stir plates. If you're like me and don't have one, shake n bake is the way to go. Doing the same thing while culturing commercial yeasts.
Click to expand...

I don't think a stirplate would help oxygenate though, I think that is helping as well.

I think I may have to look at making myself a stirplate however.
 
Supposedly the stirplate does help with oxygenation by constantly turning the wort over at the surface. It also helps keep more of the yeast in contact with the wort, instead of clumped together.

Shaking accomplishes the same thing, but a stirplate is hands-off.

I also prefer to chill the starter and decant the wort before pitching, but have been known to pitch the whole thing due to time constraints. Never had a problem with oxidation, but I'm not sure I know how to notice it either.
 
Homercidal said:
Supposedly the stirplate does help with oxygenation by constantly turning the wort over at the surface. It also helps keep more of the yeast in contact with the wort, instead of clumped together.

Shaking accomplishes the same thing, but a stirplate is hands-off.

I also prefer to chill the starter and decant the wort before pitching, but have been known to pitch the whole thing due to time constraints. Never had a problem with oxidation, but I'm not sure I know how to notice it either.
Click to expand...

I have noticed oxydiation in a few of my beers, as a sherry like, spicy, unwelcomed flavor.....not related to my starters, but rather me being an idiot.
 
I recently made a stir plate and due to technical difficulties, I don't quite have it in production yet. I made a starter on Monday night in my brand new 3000ml erlenmeyer flask using 4 cups of water and a cup of light DME. Added the yeast (wyeast 1968 London ESB for my Lagunitas IPA clone) and have been swirling it every morning and evening. There is a think layer of yeast on the bottom, and when I swirl it it breaks up and spins around the wort. It settles out in several minutes though, so a stir plate would keep all of that in suspension much better which would make a much larger cell count. I am going to pitch another 4 cups water and 1 cup DME into the starter tonight and continue to swirl for my brew day Saturday. That should give me a 2000ml starter with a decent cell count. I plan decant the liquid to get rid of any oxygenation (doubtful it matters), and split the solid yeast into another container for later use. I will pitch the other half right into the chilled wort and let it rip.
 
My understanding is when creating a starter you are not trying to make beer... you are simply trying to generate more yeast cells. To that end, don't worry about oxidation. In fact don't use an actual airlock. You want to keep bugs out but not oxygen. I have used sanitized aluminum foil before, and now use a sanitized foam stopper to allow oxygen to get into the flask.
 
Ohio-Ed said:
My understanding is when creating a starter you are not trying to make beer... you are simply trying to generate more yeast cells. To that end, don't worry about oxidation. In fact don't use an actual airlock. You want to keep bugs out but not oxygen. I have used sanitized aluminum foil before, and now use a sanitized foam stopper to allow oxygen to get into the flask.
Click to expand...

+1 I totally agree

I use an airlock between shakings, but when I am shaking I am violently aerating and shaking the wort, I get a 2-3 inch layer of foam going. The yeast seem to really like it! The pacman starter I have going is getting so thick it is almost like the consistincy of pea soup...so much yeast!
 
permo said:
I have noticed oxydiation in a few of my beers, as a sherry like, spicy, unwelcomed flavor.....not related to my starters, but rather me being an idiot.
Click to expand...
That is NOT oxidation. Oxidation is a wet cardboard like taste. Once you get it you will NEVER forget it. It is NOTHING like sherry or spicy.
 
Beer_Guy said:
That is NOT oxidation. Oxidation is a wet cardboard like taste. Once you get it you will NEVER forget it. It is NOTHING like sherry or spicy.
Click to expand...

Oxidation has more than one attribute. The cardboard flavor is unmistakable.....the weird sherry like flavor is more subtle. .... but oxidation none the less.
 
I just did a little reading on it and you are right.

From Homebrewzone.com
Description: Carboardy, papery flavor or aroma that is not acceptable in any beer style. Sherry-like is another way to describe an acceptable characteristic in many Barleywines, Old Ales, or Scotch Ales.
Click to expand...
But that must be a very mild characteristic. I cannot see ANY beer with the oxidation level I had being good. It was like I was licking my beer off the bottom of a cardboard box.
 
permo said:
I just wanted to share what i have recently learned. I used to make my starters and just leave them sit until they were done. I would add nutrient to the boil of the wort and aerate..then pitch and forget about it.

To experiement, this week i have two big starters going and about 15 times a day I have been taking the airlocks off of the starters and vigoursly shaking and aerating the wort.

If I had to take a guess, I would say, that visually it appears as if I have at least 4 times the yeast as I normally would have if I simply would have left it alone.

I am sure there is oxidation in the wort, so I am sure to dicant and just pitch slurry, but wow does shaking and aerating constantly increase cell count....from what I can see.
Click to expand...

In microbiology labs they use shakers to keep the media solution oxygenated. It is insane that a small shaker costs so much. As you can see this tiny shaker cots over $1000. Maybe one of the talented DIYers can engineer a homemade shaker for yeast cultures.
 
The nice thing that a stirplate does for you that shaking does not, is that the continuous whirlpool drives the CO2 (that the yeast can not use)out of the solution. At the same time the dimple of the whirlpool pulls air back in. That is why you want to use a lid that is permiable to air (foam, loose foil). if you use an airlock, you are only pulling CO2 trapped in the head space by the airlock back into your solution. This is fine at the begining as there is air in your head space at that time. but once enough CO2 has been produced there is no more O2 left in there.

That is the problem with the shake method as well. Don't get me wrong, it is better than nothing at all and will produce yeast, but once the yeast has produced enough CO2 to fill the head space, that is what you are shaking back into your solution.

Shaking does allow the yeast to remain in suspension though and allow the yeast to use up what O2 there is in the starter from the beginning of the process therfore definately producing more yeast than just letting it sit.
 
luthierzan said:
The nice thing that a stirplate does for you that shaking does not, is that the continuous whirlpool drives the CO2 (that the yeast can not use)out of the solution. At the same time the dimple of the whirlpool pulls air back in. That is why you want to use a lid that is permiable to air (foam, loose foil). if you use an airlock, you are only pulling CO2 trapped in the head space by the airlock back into your solution. This is fine at the begining as there is air in your head space at that time. but once enough CO2 has been produced there is no more O2 left in there.

That is the problem with the shake method as well. Don't get me wrong, it is better than nothing at all and will produce yeast, but once the yeast has produced enough CO2 to fill the head space, that is what you are shaking back into your solution.

Shaking does allow the yeast to remain in suspension though and allow the yeast to use up what O2 there is in the starter from the beginning of the process therfore definately producing more yeast than just letting it sit.
Click to expand...

I can tell you for a fact that shaking is driving at least some C02 out of the solution, I put my nose next to the opening in the bottle after a good shake, and almost passed out from C02.

I think the shaking method, really outproduces the "let it sit method" but I sure think that a stirplate would be nice....once you start to grasp the concept that the only purpose of a starter is to make more yeast, and that the process is different then fermenting beer you can start to make much smaller starters.

I just pitched a 4 liter starter last week........I bet I have the same number of yeast if not more in my 2 liter starter this week...with all aeration and agitation.
 
I did both on my first starter. I took it off the stirplate a few times in the first 12 hours, and swirled the whole flask to really give the gases a chance to exchange. I can't wait to get home and see how it is doing after 24 hours. I did notice a dramatic increase in what appears to be yeast, based on the milky look.
 

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