[a10t2]

That's most likely a significant over pitch, so no surprise there.

Edit: Assuming this is a <15 gal batch.

[HoosierBrew]

That's most likely a significant over pitch, so no surprise there.

True enough - 4 hrs is very quick, Sean. I connected with the 'quicker start' part, but not the time frame. My bad - long week !

[Wort-H.O.G.]

4 vs 6 hrs with a starter doesn't seem much different. And my starter was certainly not aggressive.

sandiego super yeast wlp090 - always takes off fast for me.

[Wort-H.O.G.]

so after 2 weeks and 3 consecutive readings, my final gravity was 1.018-this beer has always finished at 1.011-1.012 for me.

all things considered, mash temp 153F, ph 5.3, OG 1.060 and fermentation temp of 67-68F were all as they always are for this recipe. the only new variable was using the previous slurry vs. fresh yeast and starter.

Any thoughts on why the FG ended so high? got me hesitant on using the slurry ever again without knowing what may have happened.

[ynotbrusum]

I may have overpitched some batches as I said before, so I tried this weekend using the Mr. Malty calculator for a lager - I repitched in 2 ten gallon batches:  500 ml in each, as the slurry was very thin.  It was cranking by the next morning, with visible krausen.

However, when I have "overpitched" (i.e., didn't measure in any precise way), my finishing gravities were usually low (1.004 to 1.008), so I don't know about the higher FG you are experiencing.  Did you swirl the fermenter a little toward the end?  For beers that are finishing high, I try to do that and have pitched some high krausen starter in those situations with some success.

Good luck with your beer.  I wouldn't give up on pitching slurries based on this one event, however.

[Wort-H.O.G.]

I may have overpitched some batches as I said before, so I tried this weekend using the Mr. Malty calculator for a lager - I repitched in 2 ten gallon batches:  500 ml in each, as the slurry was very thin.  It was cranking by the next morning, with visible krausen.

However, when I have "overpitched" (i.e., didn't measure in any precise way), my finishing gravities were usually low (1.004 to 1.008), so I don't know about the higher FG you are experiencing.  Did you swirl the fermenter a little toward the end?  For beers that are finishing high, I try to do that and have pitched some high krausen starter in those situations with some success.

Good luck with your beer.  I wouldn't give up on pitching slurries based on this one event, however.

yeah i dont know what the deal was in this case. wlp090 on this recipe always rips thru it all very quickly. not unuasal to be done after 5 days. this one went almost 2 weeks before i got to taking a reading and kegging. i did decide to colect 1/4 cup of slurry and have got a yeast starter going just to see how that works this weekend when i fire up another round of this recipe.

[drawdy10]

Bummer man, I can't see a reason why your FG would be higher.  Sounds like you know what you are doing.


Sent from my iPhone using Tapatalk

[S. cerevisiae]

If ones does not allow for new cell growth on a pitch, one can end up with a poorly performing culture due to average yeast cell age and budding scars.  At most, one needs 150 to 200 milliliters of thick slurry to fully attenuate 5 gallons of 1.060 wort, which usually requires one to crop around 250 to 350ml of thin slurry from a primary fermentation. 

Wyeast states that thick slurry is usually composed of 40-60% yeast cells.  One milliliter of thick slurry that is composed of 40% yeast contains 1.2 billions cells; hence, 150 to 200 milliliters of thick slurry contains 180 to 240 billion cells (viable cell count requires a microscope, a hemocytometer,  and methylene blue).  Wyeast even gives a way to estimate cell count by slurry weight.  Slurry that contains 40% yeast cells weighs 1.1 grams per milliliter; hence, 150mls of 40% slurry should weigh approximately 165 grams.

The maximum cell density for 5-gallons (~19L) is 19 x 200 billion = 3.8 trillion cells.   If we are starting with 200 billion cells, then we are looking at log₂(19) = log(19) / log(2) = 4.3 (5 for good measure) replication periods after the lag phase has been exited until the culture has reached maximum cell density, which means that maximum cell density should be hit at 90 x 5 / 60 = 7.5 hours after the lag phase has been exited.  With most ale yeast strains, that figure equates to about 12 +/- 3 hours between pitching and signs of active fermentation.

[denny]

If ones does not allow for new cell growth on a pitch, one can end up with a poorly performing culture

Hold on to your seat, I'm gonna agree with you!    years ago, after i had started re;pitching on a previous slurry, I wondered if I really needed all that yeast.  I started dividing the slurry into thirds or halves and only pitching a portion of it.  It was immediately clear to me that the beer I made that way tasted better than when I used the entire slurry for another 5 gal. 1.050-1.070 batch.  No quantification, no blind tasting...it was obvious that cell growth produced a better beer.

[S. cerevisiae]

It was immediately clear to me that the beer I made that way tasted better than when I used the entire slurry for another 5 gal. 1.050-1.070 batch.  No quantification, no blind tasting...it was obvious that cell growth produced a better beer.

I originally stumbled onto this information while listening to Garrett Oliver speak back in the nineties.  He said that he periodically underpitched in order maximize new cell growth.  I started to research the subject after hearing Garrett speak. Like humans, yeast cells lose fertility and undergo metabolic changes as they age.

[denny]

Like humans, yeast cells lose fertility and undergo metabolic changes as they age.

Cue "Taxi Driver"...."you talkin' to ME?" 

[Wort-H.O.G.]

Must be the reason for a poor FG. I decided to use 1/3 cup slurry in yeast starter, and then pitched that into another batch. Already at 1.012 after 4 days and that's right on the money for this beer and wlp090. Again, lesson learned and better brewer for it!


Sent from my iPad using Tapatalk

[ynotbrusum]

I went to the Mr Malty yeast calculator and just did a repitch of US-05 using about 85ml of yeast measured in a beaker.  The 5 gallon batch took off fine (1 week from harvest from primary) at a 1.050 simple pale ale.  I can't say what the taste profile will be, but it is a significantly smaller repitch than I used previously....

[klickitat jim]

When I got into repitching I was using the suggested ml of slury, but it was usually about the consistency of thick yogurt, way more cells than that runny stuff that comes out of a smack pack. Im certain I was way over pitching. My new way will be to save a quart of swirled yeast cake, then do a starter with ~90 mls of runny stuff.

[ynotbrusum]

When I got into repitching I was using the suggested ml of slury, but it was usually about the consistency of thick yogurt, way more cells than that runny stuff that comes out of a smack pack. Im certain I was way over pitching. My new way will be to save a quart of swirled yeast cake, then do a starter with ~90 mls of runny stuff.

Yeah, for simple ales that is what I am finding to be the best route!