Infected Starter? (PICS)

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Hi HBT,
Does this starter look infected? It is a 2L starter of white labs 2206 Bavarian Lager yeast. I used one pack manufactured 7/16/2020, two cans of Propper starter, and two bottled-waters. I did a stir starter one week ago for a 36 hours and chilled in my keezer for 3 days at 45F.
MOLD?
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Enough Yeast?
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Thanks, Jon
 
For such a large starter, I'm used to seeing a lot more yeast sediment on the bottom (for ale yeast at least). Maybe this is normal for lager yeast? They stay in suspension or something?
 
A 5 gallon batch with 1.045 OG. Should be ~4.6% ABV in the end.

Given the age of the yeast, the starter size, and gravity, I'd normally pitch more yeast (for a lager). But it should get the job done.

For such a large starter, I'm used to seeing a lot more yeast sediment on the bottom (for ale yeast at least). Maybe this is normal for lager yeast? They stay in suspension or something?

It actually looks about right to me. There may still be a significant amount of yeast in suspension...hard to tell from the pics.
 
Just confirmed the "final gravity" of the starter is 1.035.
The OG started at 1.040. That doesn't seem like a lot of fermenting...
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What temperature was the starter at when it was fermenting?
About 75F, room temperature in our house.

Two things different about this starter:
1) I smacked the pack and after two hours at 75F, wife put it back in the fridge on accident for an hour. Took it out and it didn't really balloon up.
2) Manufactured on 7/16, about two months ago. Yeast calculator estimated a a 55% viability being 60+ days old. Half the viability.
 
About 75F, room temperature in our house.

It looks like there's a stir bar in the pic, so 36 hours should have been plenty of time at 75F.

Your FG is probably a little lower than what's showing (assuming fridge temp and not fully degassed (bubbles)), but that would only explain a little bit of it.

Your hydrometer isn't bottomed out on the bottom of your test jar, is it?
 
It looks like there's a stir bar in the pic, so 36 hours should have been plenty of time at 75F.

Your FG is probably a little lower than what's showing (assuming fridge temp and not fully degassed (bubbles)), but that would only explain a little bit of it.

Your hydrometer isn't bottomed out on the bottom of your test jar, is it?
Nope, made sure it was floating freely.
Wondering if the 2month age of the yeast (and 50% viability) affected it.
 
Wondering if the 2month age of the yeast (and 50% viability) affected it.

~50% (or 70% or whatever) viability wouldn't really explain the high gravity, IMO. There should have been enough cells to attenuate the starter wort in 36 hours. Any idea how the yeast was handled/stored?
 
Maybe temp a little high. Id start over and do the starter at 50-55 degrees

At least in my mind it promotes the yeast to reproduce selectivly for that temp range. I do my ales at the lowest temp possible as i ferement on the low end for everything i do. Plus i do t want to add in off flavors produced by the starter. 75 degrees for a lager yeast i would think would be stressing them out and producing alot of off flavors
 
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Maybe temp a little high. Id start over and do the starter at 50-55 degrees

75F should have accelerated attenuation, not hampered it. Lager strains are perfectly happy working in the 70s and higher. People just don't appreciate the taste of the beers they make at those temps.
 
~50% (or 70% or whatever) viability wouldn't really explain the high gravity, IMO. There should have been enough cells to attenuate the starter wort in 36 hours. Any idea how the yeast was handled/stored?
I just bought it from Northern Brewer 8/14 (a month ago). The day it arrived I immediately put it in my refrigerator. The other part of handling is how (mentioned earlier), the smack pack was smacked, sat out for an hour, and placed back in the fridge on accident for an hour. I took it out again for another 2 hours before beginning the actual starter.

Whatever the root cause is, it sounds like something is off here. I'll purchase another pack or two and try another starter. Thanks VikeMan and Buck for the help.
 
75F should have accelerated attenuation, not hampered it. Lager strains are perfectly happy working in the 70s and higher. People just don't appreciate the taste of the beers they make at those temps.

At 75 its pretty uncomfortable for lager yeast. They would be somewhat stressed there and the yeast produced could be effected by that. I dont ferment anything high, so thats coming from that opinion. I do my ale startes 55-62 , but i also use colder type ale yeast as well
 
At 75 its pretty uncomfortable for lager yeast.

I don't believe that to be true. From my experience, I can say that lager strains pretty much rip through starters in the 70s, just as fast as a typical ale strain.
 
I don't believe that to be true. From my experience, I can say that lager strains pretty much rip through starters in the 70s, just as fast as a typical ale strain.


Yea i now they can ferment high, its just not in their typical biological range they are tuned for. They will produce off flavors you will just be dimping into the beer. They should be able to rip through 50-60 no problem, that is a very effecient temp for them. That is the equivalent of an ale ferment 68-75 and i dont think many ppl are doing ale starters 80+ degrees. Ive had bad smack packs before brand new where i thought the viability was low, so these could be double screwed. Viability could have been like 10-30% if say something went wrong elsewhere.

Also with lagers it is very important to have alot of cells, im looking for 2-3x more than an ale when i start, and the oxygen needs to be higher to start as well.
 
That is the equivalent of an ale ferment 68-75 and i dont think many ppl are doing ale starters 80+ degrees.

No, but they could. Here, Lallemand cites 90-95F as the most efficient range. The beer would taste horrible, but the yeast don't mind one bit.
https://www.lallemandbds.com/wp-content/uploads/2013/06/LBDSMascoma_ThermostabilityDocument.pdf
They're talking about distiller's yeast, but it's the same species.

ETA: A more scholarly reference. See Table 2 on page 4 of this paper...
https://www.mdpi.com/2306-5710/2/4/34/pdfThe maximum growth temps for both lager and ale yeasts are quite a bit higher than the temps we normally ferment at.
 
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If there was fewer viable cells in the yeast pack and that strain has a longer lag time (time between pitching and active fermentation) the starter was probably prematurely stopped. Keep in mind that while all the strains we brew with have the Crabtree effect phenotype, they can be very different in how they balance biomass production and ethanol production in an aerobic media. Some will just lag hard after being pitched and aerated but it's nothing to worry about. It's not a bad idea to give starters more time (2.5-3 days at least) to give the yeast time to acclimate to their environment and stabilize.
 
the starter was probably prematurely stopped.
That's my take too. 36 hours is the minimum time. Especially with older or less vital yeast, many a time it already takes 2-3 days to even see the color change (becoming significantly lighter) sometimes longer. I give it 24-48 hours after the color change. I get a lot of yeast that way. My starters are 1.5 liter typically, but I can do multiple ones. Works best on my shakers.

Enough Yeast?
From the picture that does not look like much yeast at all. I recognize you're using a wide bottomed 5 liter flask with 2 quarts of starter beer. I'd expect a 1/8 - 1/4" covering the whole bottom in that flask.
 
That's my take too. 36 hours is the minimum time.

Are you talking about stirred or unstirred? My stir plate starters are almost always done within 24 hours, as long as I'm not trying to push the inoculation rate too low (i.e. trying to do a single step starter where two step would be better).
 
white labs 2206 Bavarian Lager yeast. I used one pack manufactured 7/16/2020,
The viability curve of White Labs PurePitch packs is way higher than any other packaging. Only 3% viability drop per month for the first 3 months.
But... 2206 is WYeast, so 8-10% per month decrease in viability is a decent estimate.

Now it being shipped has certainly not helped the yeast's health. Was it in a hot temp zone during transport perhaps?
 
Are you talking about stirred or unstirred? My stir plate starters are almost always done within 24 hours, as long as I'm not trying to push the inoculation rate too low (i.e. trying to do a single step starter where two step would be better).
They're on orbital lab shakers.
All inoculated starters are oxygenated and left for an hour before placed on the shakers. Inoculation rate is kept at or above the minimum of 25 million/ml. Sure, I make step starters where needed, such as with older and smaller reserves.

Let me say this, I've never seen satisfactory growth after a mere 24 hours, stirred or shaken, from a "fresh" pack. Fresh meaning less than 3 months old. I always wait for the color change from medium or darkish brown to a significantly lighter tint. It usually has become thick and creamy 24 hours after that.
 
Its not that yeast are not growing faster, higher temps will lead to a culture reproduced at a rapid higher temp, which does have effects to the yeast cell. Too many yeast can be problematic as well. I dont an issue with yeast reproduction at lower temps, it does take longer, but once a good amount is there, reproducing to 2-3x needed is not hard. The outcome is a better yeast culture with less stress going into ferment. I do try to slow the process down, and it does take longer, im just looking for a better outcome
 
Let me say this, I've never seen satisfactory growth after a mere 24 hours, stirred or shaken, from a "fresh" pack. Fresh meaning less than 3 months old. I always wait for the color change from medium or darkish brown to a significantly lighter tint. It usually has become thick and creamy 24 hours after that.

Interesting. My experience is so different that I wonder what variables might be different and how much affect they have. I'm doing sir plate and not force oxygenating (i.e. other than due to stirring). I also use wyeast nutrient in my starters.
 
The outcome is a better yeast culture with less stress going into ferment.

Can you provide any references about the higher fermentation temperatures we're talking about causing more "stress?"

ETA: I don't mean higher ester levels, etc. I mean actual harm to yeast cells.
 
Can you provide any references about the higher fermentation temperatures we're talking about causing more "stress?"

ETA: I don't mean higher ester levels, etc. I mean actual harm to yeast cells.


Just do some searches try temp, cell walls, fatty acids, ect. Rapid growth and overcrowding. Theres enty out there. If they are optimized to ferement at a given temp range, they optimized to reproduce at that range as well. Optimization is just not speed, temp is just a forced reaction.
 
Are you talking about stirred or unstirred? My stir plate starters are almost always done within 24 hours, as long as I'm not trying to push the inoculation rate too low (i.e. trying to do a single step starter where two step would be better).
Many strains will grow rapidly overnight with stirring, but that's just the first step to a healthy pitch. You want to prepare your yeast culture (starter or beer) for a healthy outcome by giving them time to reproduce and stabilize. Part of that is stepping up to your final starter volume. Pitching a small amount of healthy yeast into a large starter won't actually produce much more yeast than pitching into a smaller starter (kveik not included). Just like a beer may crap out if under pitched, so can a starter. So time on the stir plate is only part of the equation. I agree that 24 hours can produce plenty of yeast most of the time in practice though.
 
Just do some searches try temp, cell walls, fatty acids, ect. Rapid growth and overcrowding. Theres enty out there.

Can you please provide your best example of something scholarly that actually states cells will be harmed fermenting at the temps we're talking about? Given that (IMO) you are making an argument that to my knowledge hasn't been made or accepted before (I haven't seen it in more than a decade of reading copious qtys of papers on brewing), I think that's a reasonable request.
 
Just like a beer may crap out if under pitched, so can a starter.

I'm not sure what I might have said to the contrary to have that directed at me, but I agree.
 
From the looks of the first picture and the s.g. reading, it wasn't done when you put in the keezer. You didn't mention whether it was on a stir plate?

We don't really know how much yeast is in the pack to start with right? The pack could have been treated poorly. If the 1.035 reading is correct, the yeast hadn't done much work yet. I look for my yeasts to form a krausen. Usually at least a day and then perhaps 2. I plan on 36- 48 hours though.
 
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