Settled Yeast Slurry Vs Cloudy Mixed Yeast Slurry

[Dornbox]

Approximately 5 weeks ago, for the first time ever, I pulled a couple pint sized mason jars of slurry off my uni tank. Now I have these beautiful Jars with solid 1" thick yeast cakes in the bottom that I'm trying to figure out some sort of pitching rate with. When people talk about pitching slurry, estimated cell counts and densities, are they including the old beer that is now separated in my jars? I think prefer to pour off the old beer an pitch my cakes into a starter for 24+ hours as I feel like I would rather grossly over pitch than under (this will be for an Oktoberfest / Lager). But I have no idea what people are including when referring to slurry and I haven't read anything that clearly talks about settled yeast slurries vs jars full of beer and yeast mixed slurry when estimating cell counts. Should I pour off the beer and measure the cake, mix up the jar and measure the mix, pour off the beer and build a starter with the cake. I'm lost and I need this yeast for Friday evening. Any experiences and advice reusing yeast would be super appreciated especially simple advice based on experience. I have no desire to look at my slurry under a microscope. Maybe in a year or few but for now water chems are occupying my brain power. Many many thanks!

Summery of finer points: I'll be pitching into 12-13 gallons of 1.060 or under wort with a Wyeast 2633 Oktoberfest Lager yeast that was pulled from a uni about 5 weeks ago. The yeast was initially pitched from (3) packs built up in a 3 liter starter at the end of March.

 

[Ward Chillington]

I think prefer to pour off the old beer an pitch my cakes into a starter for 24+ hours as I feel like I would rather grossly over pitch than under (this will be for an Oktoberfest / Lager).

You think correctly @Dornbox . From your settled jars, dump off the cloudy liquid or often referred to "supernatant" then pitch the rest. The cloudy liquid at worst is gonna be full of off flavors and not worth introducing into your wort. That's the simple answer but just to hit on a couple of fine points....were your pint jars and lids sterilized and did you store the slurry in a cold, upper 30°F fridge? What's the color like? If it's getting peanut buttery looking you are looking a more dead cells than live. What kind of beer was this harvested from? Lower OG stuff (1040-1050 ish) is better than high especially for what you are planning on pitching this into, you want lively yeast, not tired...but you could do a starter with the slurry then pitch that. Also, slurry stratifies...I think the order is trub on the bottom, yeast then beer...and don't worry about any trub sticking to the jar...it'll still be trub in this batch!

WRT your how much question, look around the web for the pitch calculator you like, BF 's is just as good as any... Live yeast cells die off at a predictable rate just like what your Wyeast package outlined but they give you a starting place of how many billion live cells they say are in the pouch the day they sealed the bags. With slurry, it's less absolute, ie, how many cells are you starting with but now we are getting academic but you'll find plenty of brewers here that have pitched with as old slurry if not older including myself.

Lastly...don't hurry this and have plan B. 15 gallons of wort is a lot of beer to dump. There is a ton of how to out on the web about this practice so go get more "brain power" with some screen time with Google, a simple entry like 'reusing yeast slurry, brewing" will have a ton of returns in articles, postings from forums like this to videos. It sounds like you've got a pretty good foundation to do this so best of luck, and let us know how it goes!

 

[Dornbox]

.were your pint jars and lids sterilized and did you store the slurry in a cold, upper 30°F fridge? What's the color like? If it's getting peanut buttery looking you are looking a more dead cells than live. What kind of beer was this harvested from?

@Ward Chillington many thanks for your reply. To circle back" I pulled the yeast off the bottom of my uni tank with the idea to pitch it so the jars and lids were boiled, star sans, and stored in my fridge around 34°F. The yeast cakes are nice and clean and are a creamy off white color. The striated beer in the jar above the yeast cake is crystal clear. The yeast looks as healthy as the day I pulled it. I'm actually repitching it into the same beer that it was pulled from but a couple of points lower than the original and minus some melanoidin that I accidently overdosed / doubled in the previous batch. The OG beer was 1.061 and this one will be 1.057. I'm just really confused because everything I'm finding on using slurry is more like my jars looked like when I first pulled the yeast, thin and creamy. My jars look like 4" of brilliantly clear beer sitting on a 1" thick healthy looking yeast cake.

 

[Ward Chillington]

Like this?

This got used 3 months later...I think it was Voss. Maybe do a starter with your slurry...a liter of oxygenated 1040 DME with some nutrient to your slurry...watch your temps...don't shock the yeast...if the fermentation stalls, plan B .

 

[HighVoltageMan!]

Yeast cake, with little trub, has @ 250 billion cells per 1/4 cup. Kind of easy to remember. If you have @ 1" in a pint jar, you yeast count is @500 billion cells between the two jars. So, by my guess, it's a under pitch in a lager. Not only that, but the yeast are a little old to re-pitch or at least by my way of thinking. You will need @ 850 billion cells for a 11 gallon, 1.057 beer.

You could take one jar and assume it has 200 billion cells and get 800 billion cells from a 5 liter starter for 1.4 pitch rate. Or you could use both jars and build a 5 liter starter and get @1000 billion cells (that sounds English) for 1.83 pitch. You could do either today, it will finish tomorrow, crash cool over night and be ready by Friday. I like lots of yeast when brewing lagers, 2.0 pitch or bigger, they just turn out better. Don't forget to aerate the living p!55 out of it when pitching, pure O2 if possible, or just shake the day lights out of it for a couple of minutes after pitching.

Good luck!

 

[Dornbox]

Like this? Thus got used 3 months later...I think it was Voss. Maybe do a starter with your slurry...a liter of oxygenated 1040 DME with some nutrient to your slurry...watch your tempatures...don't shock the yeast...if the fermentation stalls, plan B .

Exactly! A little less in my jars in terms of yeast but that looks very similar. the stratification is dead on.

I have some smack packs for a dunkle I was planning so if I need a plan B, I got it. I'll pull my slurry out of the fridge this evening and let it sit on the counter for a couple hours then pitch it into a 2 liter starter on a stir plate and let go until Friday evening. The yeast was a slow starter last time I pitched it so I wait a couple days and direct pitch my smack packs on Sunday evening if I'm not happy with my bubbles.

The question is though, do I use bot my mason jars? Each cake is about 1" thick. I'd have to think there's about 3x or more yeast in each jar vs a whitelabs yeast stick pack.

Many thanks!

 

[Dornbox]

Yeast cake, with little trub, has @ 250 billion cells per 1/4 cup. Kind of easy to remember. If you have @ 1" in a pint jar, you yeast count is @500 billion cells between the two jars. So, by my guess, it's a under pitch in a lager. Not only that, but the yeast are a little old to re-pitch or at least by my way of thinking. You will need @ 850 billion cells for a 11 gallon, 1.057 beer.

You could take one jar and assume it has 200 billion cells and get 800 billion cells from a 5 liter starter for 1.4 pitch rate. Or you could use both jars and build a 5 liter starter and get @1000 billion cells (that sounds English) for 1.83 pitch. You could do either today, it will finish tomorrow, crash cool over night and be ready by Friday. I like lots of yeast when brewing lagers, 2.0 pitch or bigger, they just turn out better. Don't forget to aerate the living p!55 out of it when pitching, pure O2 if possible, or just shake the day lights out of it for a couple of minutes after pitching.

Good luck!

@HighVoltageMan! I like it! Many thanks. I also love the "yeast cake, with little trub, has @ 250 billion cells per 1/4 cup. If you have @ 1" in a pint jar, you yeast count is @500 billion cells between the two jars" part to. As you said, easy to remember.

Thanks again!

 

[HighVoltageMan!]

The question is though, do I use bot my mason jars? Each cake is about 1" thick. I'd have to think there's about 3x or more yeast in each jar vs a whitelabs yeast stick pack.

Because of trub, dead cells and other junk, the yeast count isn't as high and you would expect. 250 billion per 1/4 cup (2 ounces) is about the right count from my experience. By my estimation you have 400-500 billion cells and they are old. It's an under-pitch for that volume and gravity of that beer. If you build a starter, the yeast you get out of it are mostly very young and produce the best beers.

 

[GFHomebrew]

I go by pure pitch 1ml = 1 billion cells how many mL of yeast have you got then thats how many billion cells.
This is assuming fresh viable yeast then just reduce cells/ML if older or if trub mixed in with yeast.
good luck

 

[Ward Chillington]

Good fill in on the details guys...attaboyz and thanks @HighVoltageMan!
@Trialben

Getting the older yeast to wake up in a starter rather than the wort sounds like the better route and yeah...aerate that wort!

 

[The Brew Mentor]

If I use recovered yeast that's more than a week old, I will always do a starter. I don't like the lag time and after a week, it'll take it's time getting going.
After 2 weeks I'm much less likely to use it as it seems viability goes down too much.
So at minimum, with what you have, I'd decant most of the beer on top (drinking it is fine) then add to a starter. After a day you'll know how it reacted and if it struggled at all, I'd consider dumping it or making another starter and adding it to it.
Decant the spent beer before pitching.
.I also like to have plan B such as dry yeast at the ready.
Good luck
Brian

 

[Donoroto]

I often save yeasts for a few months. A starter is always a good idea, I keep some DME so I can mix up a batch of 1.040 wort anytime

 

[Dornbox]

So as a follow up, I used close to 2” of settled 2633 Oktoberfest yeast cake which started as (2) 1 pint mason jars of unwashed slurry. i poured off the settled top layers of beer and I added the remaining cakes to a 2 liter1.060 starter on a stirrer plate for 24 hours. I pitched the starter in close to 13 gallons of 1.058 wort. About 12 hours later I had a consistent and strong burping through my blowoff. Worked like a champ!

For comparison, nearly the same beer with a 2 liter starter made from 2 fresh packs of the original yeast plus a 3rd pack directly pitched, took closer to 48 hours to kick off. A slight under pitch I believe but the yeast is also known to be a slow starter according to the googles.

Anyway, super happy with a successful brew thanks to everyone on this thread!

 

[Ward Chillington]

I added the remaining cakes to a 2 liter1.060 starter on a stirrer plate for 24 hours.

Starters typically are of a lower gravity wort so too wake them up in a more hospitable environment. Remember, the goal with a starter is to make bio-mass, not alcohol; which much like for humans, too much will kill you...the yeast is the same way. It sounds like this went off just fine...keep us up on the progress!

 

[Dornbox]

Typo! Starter was 1.050!

Thanks again!