Author Topic: Yeast starter cloudy after cold crashing  (Read 2328 times)

Offline babychef

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Yeast starter cloudy after cold crashing
« on: February 26, 2018, 07:25:28 PM »
I made a yeast starter with Wyeast 2206 Bavarian Lager yeast for a lager I will be brewing in a couple of days. Fermented the starter in 2.8 L wort on a stir plate for 18 hours. It fermented actively, with a healthy krausen. I then cold crashed for 48 hr (was planning only 18 hr, but had to delay brew day). However, as opposed to previous yeast starters I have made, after cold crashing, although there is a thin white layer of presumably yeast on the bottom of the flask, the "beer" above it is still cloudy. In the past, I always decanted my starter before pitching it to avoid any off flavors from the starter "beer." However, I am concerned that this starter cloudiness may still represent yeast in suspension, and I would be wasting those cells if I decanted.

So, what would you recommend? Should I not worry so much about the cloudiness, and go ahead and decant before pitching? Should I pitch the whole 2.8 L volume to get every yeast cell available, and not worry about the starter affecting the final beer flavor? Should I actually be concerned that the cloudiness represents contamination, although I was very careful with sanitation?

Also, after cold crashing, how long can a starter be kept in the refrigerator prior to pitching? Will it hurt the yeast if it is not pitched for 3 days, 4 days, 5 days, etc?

Thanks.

Offline GigaFemto

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Re: Yeast starter cloudy after cold crashing
« Reply #1 on: February 26, 2018, 08:13:51 PM »
I wouldn't worry about the cloudiness too much. 18 hours before cold crashing is not a lot, so the yeast may not have been finished and ready to go into hibernation. I wouldn't pitch all the liquid - I usually decant most of it and just keep enough to swirl up the thick yeast at the bottom and make it pourable. You could taste the liquid and decide whether it is something you want in your beer, but I am pretty sure that the answer will be no. The percentage of yeast cells you will be wasting by decanting the liquid is small, and once they start growing in the beer they will multiply so fast that it is only a matter of minutes or hours before they make up the difference. You can keep a yeast starter in the refrigerator for a long time before pitching. The packages you buy in the store are supposed to be good for 6 months, so if you have yours in good conditions for a few days or even a couple of weeks it should be no problem at all. Yeast, being living organisms, are much hardier than many people seem to give them credit for. If they were really fragile they would not still be here.

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Offline Ck27

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Re: Yeast starter cloudy after cold crashing
« Reply #2 on: February 27, 2018, 01:39:42 AM »
I wouldn't worry about the cloudiness too much. 18 hours before cold crashing is not a lot, so the yeast may not have been finished and ready to go into hibernation. I wouldn't pitch all the liquid - I usually decant most of it and just keep enough to swirl up the thick yeast at the bottom and make it pourable. You could taste the liquid and decide whether it is something you want in your beer, but I am pretty sure that the answer will be no. The percentage of yeast cells you will be wasting by decanting the liquid is small, and once they start growing in the beer they will multiply so fast that it is only a matter of minutes or hours before they make up the difference. You can keep a yeast starter in the refrigerator for a long time before pitching. The packages you buy in the store are supposed to be good for 6 months, so if you have yours in good conditions for a few days or even a couple of weeks it should be no problem at all. Yeast, being living organisms, are much hardier than many people seem to give them credit for. If they were really fragile they would not still be here.

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Yep, ive had a starter of some good old burton ale yeast in the fridge for 6 days now, I need to pitch it into something just haven't come up with a beer that I wanna use it in.

It should keep as long as 6 months if you keep it properly stored, just cover the top with aluminum foil and you are good to go.

At the 6 month point just make up some more wort and add it and let it ferment again, to refresh the yeast cells health.

Offline Oginme

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Re: Yeast starter cloudy after cold crashing
« Reply #3 on: February 27, 2018, 05:58:07 AM »
I pretty much agree with GigaFemto's comments.  I will add that most of the fine yeast left in suspension after 48 hrs cold crash are poor flocculating yeast.  Trying to keep all of that will lead to a longer time trying to clarify your beer in the end.  Aside from that, you would be surprised at how few yeast cells it takes to make the wort cloudy.

I just finished a run of lagers with WY2206 making 6 lagers over 10 weeks using 1 smack pack of yeast and overbuilding my starters.  Especially with that long run of starters and pitches, you can easily overwhelm the more floccculant yeast cells and end up with a beer that just won't clear.

With lager yeasts, I usually give it a bit longer on the stir plate to get the cell count up.  My experience is that even at room temperatures, the lager yeasts tend to grow, multiply and ferment slower and it showed with my cell counts.  I now let the cooler fermenting yeasts go 36 hours before chilling and then cold crashing.

In terms of storage, I would go a bit on the conservative side.  I've kept yeast left over from a starter in the refrigerator for 8 to 9 months and, though I was able to grow it back up to a viable starter, I found very weak cell walls and poorly attenuating yeast pitch from anything over 3 to 4 months old.  The long storage causes the yeast to use up its reserves of sterols and nutrients and they don't replicate well or efficiently.  The other thing to remember is like in the original package, the number of viable cells decreases with time.  I believe this happens a bit faster with yeast from a starter than in the original package, though I only have a few data points to verify this.
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Offline babychef

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Re: Yeast starter cloudy after cold crashing
« Reply #4 on: February 27, 2018, 08:10:49 AM »
This has been great advice. Next time, I will let my lager yeast stay longer on the stir plate. Also, I will go ahead and decant. Lastly, I suspected I could keep the yeast in the fridge at least until the 6 month expiration date, but now I have some support for, at least, that. Thanks.

 

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