Overbuilding yeast starters vs top cropping

[beervoid]

Did you say how much you took, initial volume and then what percent was yeast after settling? I can’t really provide input, but I’d guess this will be essential info to answer your question.

About 250ml in total from a 17.5liter batch

I've done another reading 2 days later after raising temp and rousing the keg.
Sill stuck at the same gravity.

I've decided to pitch half of the top cropped yeast back into the batch and hope it will restart again...

Wondering what I've done wrong

Perhaps Perhaps bierhaus15 or HTH1975 can chip in?

 

[HTH1975]

imo, skimming would not stall your beer - you should still have plenty of yeast available in solution at the very least.

What SG are you getting now? What was expected FG?

 

[beervoid]

imo, skimming would not stall your beer - you should still have plenty of yeast available in solution at the very least.

What SG are you getting now? What was expected FG?

Og is 1.075. went down to 1.052 with good fermentation and alot of airlock activity for 2 days then I cropped and airlock activity slowed down. Meassured again on day 5 it dropped to 1.042. meassured again on day 7 still at 1.042.
Getting a burp of air every 5 seconds or so.
Final gravity should be around 1.017 with 70% attenuation from wlp066 london fog

 

[HTH1975]

Og is 1.075. went down to 1.052 with good fermentation and alot of airlock activity for 2 days then I cropped and airlock activity slowed down. Meassured again on day 5 it dropped to 1.042. meassured again on day 7 still at 1.042.
Getting a burp of air every 5 seconds or so.
Final gravity should be around 1.017 with 70% attenuation from wlp066 london fog

What temperature have you been fermenting at? Have you tried rousing the yeast? Some British strains do like rousing towards the end.

 

[beervoid]

What temperature have you been fermenting at? Have you tried rousing the yeast? Some British strains do like rousing towards the end.

18c and raise it slowly towards 20c ihere im at right now. Also roused the keg but no difference.

 

[HTH1975]

18c and raise it slowly towards 20c ihere im at right now. Also roused the keg but no difference.

Starting off at 18C isn’t too bad, but I’d normally let the yeast free-rise to 22C.

Stalling so high is a bit of a mystery. I’d probably build a big starter with something like Saf-04 and pitch that.

 

[beervoid]

Starting off at 18C isn’t too bad, but I’d normally let the yeast free-rise to 22C.

Stalling so high is a bit of a mystery. I’d probably build a big starter with something like Saf-04 and pitch that.

So its not possible by harvesting liquid too early and after cropping foam I might have stolen too much yeast?
I used a liquid out tube to push out 200ml with a floating diptube that draws from the top of the beer. This was at approx 24hours.
After 48hours i cropped the krause and added this to the liquid. Total amount was 250ml in 1 jar.
Batch is 17.5liters.

I repitched half of the cropped krausen back. Temp is at 20c I got little more airlock activity

 

[HTH1975]

So its not possible by harvesting liquid too early and after cropping foam I might have stolen too much yeast?
I used a liquid out tube to push out 200ml with a floating diptube that draws from the top of the beer. This was at approx 24hours.
After 48hours i cropped the krause and added this to the liquid. Total amount was 250ml in 1 jar.
Batch is 17.5liters.

I repitched half of the cropped krausen back. Temp is at 20c I got little more airlock activity

Top cropping at that stage seems weird to me, it’s certainly not the way I’ve ever been shown to do it. I’ve always been told to skim once the beer is a couple of points above FG when we put the beer on chill.

I’d rouse the yeast and get the temperature up to 21-22C. If you get no activity or change in SG at that point, then I doubt you ever will.

 

[isomerization]

For top cropping, I used to take gravity readings but now just crop the larger second krausen after the first krausen and "dirt" - hop oils, ect has been removed or pushed to the side. This is typically around 48 hrs or 55% attenuation. Viability on this yeast has been very high, typically 96-98%

Just quoting the advice from earlier, I don’t see a recommendation to take actual liquid? And not until 55% attenuation (~48 hrs). Just FYI as it looks like went way earlier than that by attenuation (longer lag time this batch maybe)?

 

[beervoid]

Just quoting the advice from earlier, I don’t see a recommendation to take actual liquid? And not until 55% attenuation (~48 hrs). Just FYI as it looks like went way earlier than that by attenuation (longer lag time this batch maybe)?

Dont think there is a lag time as the fermentation took off pretty wild, got blowoff in the airlock and lots of airactivity.. it just died down very fast... normally I would be close to FG at that point but now im not even half the way.
It has to be that I harvested to early I can't imagine why else it would behave so strange...

 

[beervoid]

Top cropping at that stage seems weird to me, it’s certainly not the way I’ve ever been shown to do it. I’ve always been told to skim once the beer is a couple of points above FG when we put the beer on chill.

I’d rouse the yeast and get the temperature up to 21-22C. If you get no activity or change in SG at that point, then I doubt you ever will.

I've added more, roused and will raise the temp tomorrow, there is def more air activity now so it's doing something.

Cheers

 

[isomerization]

Dont think there is a lag time as the fermentation took off pretty wild, got blowoff in the airlock and lots of airactivity.. it just died down very fast... normally I would be close to FG at that point but now im not even half the way.
It has to be that I harvested to early I can't imagine why else it would behave so strange...

My point is, based on the numbers you provided (at the indicated times), you were apparently not very far into fermentation. Looks like 30% apparent attenuation at 48 hours (1.075 to 1.052), and you said you took 0.2 L at 24 hr, so even if you totally halted fermentation, that’s below the recommended 55% aa.

 

[beervoid]

My point is, based on the numbers you provided (at the indicated times), you were apparently not very far into fermentation. Looks like 30% apparent attenuation at 48 hours (1.075 to 1.052), and you said you took 0.2 L at 24 hr, so even if you totally halted fermentation, that’s below the recommended 55% aa.

Yes gotcha, I will be retrying this top cropping again. Just pondering over the cause of my halted fermentation.
Thanks for replying... Love the work you done on the Tree House Yeast thread btw.. Read the whole thing!

 

[isomerization]

Yes gotcha, I will be retrying this top cropping again. Just pondering over the cause of my halted fermentation.
Thanks for replying... Love the work you done on the Tree House Yeast thread btw.. Read the whole thing!

If this normally doesn’t happen, then I’d blame the top cropping.

Appreciate your interest! The thread was a total group effort, so much cool info in there, and still going too.

 

[bierhaus15]

Top cropping should not affect fermentation or gravity. I don't know of any instances where it would, other than cropping too early in a traditional UK rousing system where you need yeast and 02 mixing. And even then it is a maybe. Per timing, most professional literature and practice is to top crop around 50-60% attenuation - or - at second krausen. These times won't always align, so you could be cropping earlier or later into the process. It is also yeast strain dependent, some yeasts take longer for the second krausen to fully form, like W1318. That said, don't get too concerned with the exact process or timing. Look for the second krausen with some active fermentation.

Per getting beer with the yeast, that is fine, as it keeps the yeast healthy and once the yeast settles forms a barrier to contamination. A brewery I worked for top cropped 1000 bbl fermentors of Chico at 5-6 plato. Yeast slurry was a bit thin, but viability was consistently 96-99%.

 

[beervoid]

Top cropping should not affect fermentation or gravity. I don't know of any instances where it would, other than cropping too early in a traditional UK rousing system where you need yeast and 02 mixing. And even then it is a maybe. Per timing, most professional literature and practice is to top crop around 50-60% attenuation - or - at second krausen. These times won't always align, so you could be cropping earlier or later into the process. It is also yeast strain dependent, some yeasts take longer for the second krausen to fully form, like W1318. That said, don't get too concerned with the exact process or timing. Look for the second krausen with some active fermentation.

Per getting beer with the yeast, that is fine, as it keeps the yeast healthy and once the yeast settles forms a barrier to contamination. A brewery I worked for top cropped 1000 bbl fermentors of Chico at 5-6 plato. Yeast slurry was a bit thin, but viability was consistently 96-99%.

I repitched half of the top cropped yeast back in and im getting good activity again, I will report back where this finishes.