Overbuilding yeast starters vs top cropping

[HTH1975]

I'm sorry, I was probably not very helpful. I was just saying that when I visited Stoke-On-Trent, there was no counting or even a tight amount of starter, slurry, etc., that they used. They literally filled two 5-gallon buckets and dumped it into an open fermentor. I loved their beer.

Sounds familiar

 

[user 246304]

At work (a North Yorkshire brewery) we skim (top crop) when we’re about to put the beer on chill to drop the yeast out and stop fermentation (approx day 4-5). The beer then gets transferred to CT before being racked to casks.

Thank you, HTH, very helpful. I would like to ask some questions below, and hope I'm not abusing your generosity. Getting some information from a practicing Northern England brewer basically geeks me out.

One thing I'm trying to figure out is Black Sheep's very gradual drop from fermentation temp of 20-21C down to 10C, over no less than 36 hours. They then hold here 2 days, and the brewer indicated, if I'm not mistaken, this is their diacetyl rest (puzzled by a drop in temp as a diacetyl rest, that's all). Excess yeast is removed, and it goes to a CT for 24-48 hours. They then rack to cask. They do mention yeast counts, both in the CT and when racked to cask. I don't know if these are counted in lab each time, or by sheer practice they can be confident of their counts at these stages?

The comment "excess yeast is removed" - would this be the harvest?

I was curious about this gradual drop, and to 10C at that. It doesn't seem they do any chill to encourage drop out. Do I understand it correctly? Any thoughts on this?

I imagine their CT is also at 10C. I know many breweries, like yours, if have it correctly, begin a secondary fermentation in the CT as they are closed. Not much, but some. Any issues with racking to cask, or are they filled on counterpressure?

I don't have a microscope and cannot count yeast. I'd like to rack without priming, just depend, as the Black Sheep brewer said, "we have plenty of residual sugar and yeast." Am I inviting broad inconsistency, or is their a protocol that might allow for this?

Finally, this involves more at the "pub" (my living room) than earlier at the "brewery" (my back yard - where today it's -6C now, -15C by tomorrow). Many suggestions to finish cask conditioning before fining. I imagine that means you remove the shive, fine, replace with a new shive, and roll the cask a bit. Is this correct? Is this waiting in order to ensure you have enough yeast in solution to do their conditioning job?

Thanks HTH, as usual. Hope I haven't drowned with questions.

 

[user 246304]

Sounds familiar

Ian, can't remember last name, great guy. Titanic.

 

[beervoid]

One thing I'm trying to figure out is Black Sheep's very gradual drop from fermentation temp of 20-21C down to 10C, over no less than 36 hours. They then hold here 2 days, and the brewer indicated, if I'm not mistaken, this is their diacetyl rest (puzzled by a drop in temp as a diacetyl rest, that's all).

This is an interesting piece of info which if I understand correct indicates that their yeast cleans up diacetyl even at lower (10c) temperatures?
I would be curious to know if this is yeast dependent and which yeast they use.

 

[HTH1975]

Thank you, HTH, very helpful. I would like to ask some questions below, and hope I'm not abusing your generosity. Getting some information from a practicing Northern England brewer basically geeks me out.

One thing I'm trying to figure out is Black Sheep's very gradual drop from fermentation temp of 20-21C down to 10C, over no less than 36 hours. They then hold here 2 days, and the brewer indicated, if I'm not mistaken, this is their diacetyl rest (puzzled by a drop in temp as a diacetyl rest, that's all). Excess yeast is removed, and it goes to a CT for 24-48 hours. They then rack to cask. They do mention yeast counts, both in the CT and when racked to cask. I don't know if these are counted in lab each time, or by sheer practice they can be confident of their counts at these stages?

The comment "excess yeast is removed" - would this be the harvest?

I was curious about this gradual drop, and to 10C at that. It doesn't seem they do any chill to encourage drop out. Do I understand it correctly? Any thoughts on this?

I imagine their CT is also at 10C. I know many breweries, like yours, if have it correctly, begin a secondary fermentation in the CT as they are closed. Not much, but some. Any issues with racking to cask, or are they filled on counterpressure?

I don't have a microscope and cannot count yeast. I'd like to rack without priming, just depend, as the Black Sheep brewer said, "we have plenty of residual sugar and yeast." Am I inviting broad inconsistency, or is their a protocol that might allow for this?

Finally, this involves more at the "pub" (my living room) than earlier at the "brewery" (my back yard - where today it's -6C now, -15C by tomorrow). Many suggestions to finish cask conditioning before fining. I imagine that means you remove the shive, fine, replace with a new shive, and roll the cask a bit. Is this correct? Is this waiting in order to ensure you have enough yeast in solution to do their conditioning job?

Thanks HTH, as usual. Hope I haven't drowned with questions.

The drop to 10C is done when SG is around 2 points from FG. This is to encourage the yeast to drop and thus stop fermentation.

There is no specific diacetyl rest where we raise the temperature. The yeast cleans up any ‘green’ flavours during the conditioning period.

I’d be surprised if they specifically do yeast counts in the CT before racking to cask. Maybe a few times a year as a QC measure, but I’d imagine they’re confident in their process.

The only way I’ve ever seen any brewery rack to cask is to add finings then dump the beer on top. The yeast will (slowly) finish the final two gravity points in the cask, but there will be some CO2 dissolved anyway (the beer engine and sparkler blast life into the beer when serving a pint).

Casks are stored at 10-12C, this is typical cellar/serving temperature. If the casks are stored in ambient temperatures, the beer gets much too lively and you end up with foamy beer at the pump.

With a minimum 24 hours stillage, storage at cellar temperature and the finings, this gives a clear pint with the right body and carbonation.

Hope that answers your questions

 

[user 246304]

The drop to 10C is done when SG is around 2 points from FG. This is to encourage the yeast to drop and thus stop fermentation.

There is no specific diacetyl rest where we raise the temperature. The yeast cleans up any ‘green’ flavours during the conditioning period.

I’d be surprised if they specifically do yeast counts in the CT before racking to cask. Maybe a few times a year as a QC measure, but I’d imagine they’re confident in their process.

The only way I’ve ever seen any brewery rack to cask is to add finings then dump the beer on top. The yeast will (slowly) finish the final two gravity points in the cask, but there will be some CO2 dissolved anyway (the beer engine and sparkler blast life into the beer when serving a pint).

Casks are stored at 10-12C, this is typical cellar/serving temperature. If the casks are stored in ambient temperatures, the beer gets much too lively and you end up with foamy beer at the pump.

With a minimum 24 hours stillage, storage at cellar temperature and the finings, this gives a clear pint with the right body and carbonation.

Hope that answers your questions

That's great. Many thanks, HTH. Just finding a solution for my home "bar," simple affair temp controlled, enough room for two pins. Very excited to hone in on your tradition, best as I'm able.

 

[HTH1975]

That's great. Many thanks, HTH. Just finding a solution for my home "bar," simple affair temp controlled, enough room for two pins. Very excited to hone in on your tradition, best as I'm able.

No problem, you’re very welcome.

 

[isomerization]

Not really different when it comes to yeast. Every brewery, home or professional, starts with 1 loop of yeast and grows it up from there. The principles are the same.

Also, the intention of yeast starters is not to make healthy yeast, its purpose is to grow yeast for pitching. The residual liquid from a starter is not an ideal environment for yeast storage; containing very low ABV, little to no isomerized alpha (anti-bacterial), and full of residual yeast byproducts like acetylaldehyde and diacetyl. The whole benefit of top cropping is that you are harvesting the yeast at the peak of their reproductive cycle. Done properly there is very little risk of bacterial contamination (unlike bottom harvested yeast) and the yeast glyogen reserves are at their highest and stay high when stored cold. The residual sugar collected with the yeast ferments out leaving an environment free of oxygen and hostile to other wild yeast/contaminates.

What else can we argue about?

Since this thread went in a more productive direction, I will just reinforce that I was not talking about top cropping. I was comparing harvesting yeast for long term storage (over a month), specifically overbuilt yeast starter versus fully fermented beer.

I will defer to your experience with top cropping for yeast storage, but unless you have plans to use the yeast as is (so no new starter), harvesting post fermentation introduces unnecessary risk.

 

[beervoid]

Tested out top cropping on day 2.

Gravity dropped from 1.075 to 1.052 when I cropped but airlock activity seems pretty slow atm. Took a sample on day 5 so 2 days after cropping and slowing of fermentation it went down to 1.042.
Can top cropping result in slowing down fermentation?
Did I top crop too early?
Can one top crop too much?

 

[isomerization]

Tested out top cropping on day 2.

Gravity dropped from 1.075 to 1.052 when I cropped but airlock activity seems pretty slow atm. Took a sample on day 5 so 2 days after cropping and slowing of fermentation it went down to 1.042.
Can top cropping result in slowing down fermentation?
Did I top crop too early?
Can one top crop too much?

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.

 

[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.