Slurry lag versus fresh pitch

[Off Balance Brewing]

Yes I know a starter will reduce lag

Yes I've heard slurries older than 2 weeks should have a stater.

I use the simple yeast harvest approach but I typically rotate 2 strains and brew monthly. So my slurries are usually 2 or 3 months old. I've never had an issue with direct pitching about 8 to 10 oz of slurry except longer lag. I pitch more due to longer storage.

My question is why is this not the case with fresh liquid pitches? Why can omega for example have a 5 month shelf life for a 1.060 beer pitch and usually fires 12 to 24 hours versus my 24 to 48 hour slurry? Are they packing the fresh count for 5 months of decay? I thought I've heard 50 percent cell count drop over 4 weeks. Are they really providing over a billion cell count fresh?

Or is there some other change I can do to my storage method to reduce lag?

 

[RM-MN]

Yes I've heard slurries older than 2 weeks should have a stater.

Do a search for yeast viability. There is more hype about starters than there is truth. For instance, people say you have to have a large starter for a lager since it will be fermented at a cool temp. Gordon Strong, a 4 time Ninkasi award winner, has said that the often make a batch of lager and pitches a single smack pack. Wouldn't a Ninkasi award winner know what good beer is? Wouldn't he try to make it the best possible for his own consumption? What does he do to make a single pack ferment his lager properly while other people argue that you can only do that by making a starter and then step it up to a bigger starter?

 

[Off Balance Brewing]

Yeah I agree. I think that starters can only help but aren't a must. I've also read the info on vitality starters being just as effective as full cell count increase starter.

I tried searching lag time info for slurries but didn't come up with much. My bigger question was how fresh pitch packs can have a 3 to 5 month shelf life and my slurry only has a two week without a secondary wake up step.

 

[McMullan]

If wet yeast are stored at high cell density for months, apart from significant drops in cell viability and vitality, both of which risk underpitching therefore poor fermentation performance, there's a risk of selecting for storage performance rather than fermentation performance. Yeast suppliers/labs are packaging freshly cultured quality-controlled yeast in tip-top condition whereas most home brewers storing wet yeast for months probably aren't. There is no substitute for freshly prepped wet yeast. Once prepped it's all downhill, biologically, if they aren't pitched within days. Otherwise they'd be breaking fundamental laws of physics.

 

[McMullan]

Do a search for yeast viability. There is more hype about starters than there is truth. For instance, people say you have to have a large starter for a lager since it will be fermented at a cool temp. Gordon Strong, a 4 time Ninkasi award winner, has said that the often make a batch of lager and pitches a single smack pack. Wouldn't a Ninkasi award winner know what good beer is? Wouldn't he try to make it the best possible for his own consumption? What does he do to make a single pack ferment his lager properly while other people argue that you can only do that by making a starter and then step it up to a bigger starter?

Maybe he doesn't want to give too many secrets away? It is possible. But I agree, the often recommended huge starter volumes for lagers is questionable. The enzymes translated by lager yeasts are adapted to function efficiently at lower temperatures. So it's not really that valid to worry too much about assumed lower reaction rates at lower temperatures. The key, in my experience, is use freshly prepped or freshly harvested yeast. The fresher the better.

 

[RM-MN]

I tried searching lag time info for slurries but didn't come up with much. My bigger question was how fresh pitch packs can have a 3 to 5 month shelf life and my slurry only has a two week without a secondary wake up step.

Take a look at this article. It might give you some idea of your yeast's shelf life.

http://www.woodlandbrew.com/2012/12/refrigeration-effects-on-yeast-viability.html

 

[Off Balance Brewing]

Take a look at this article. It might give you some idea of your yeast's shelf life.

http://www.woodlandbrew.com/2012/12/refrigeration-effects-on-yeast-viability.html

Interesting data. Prolly helps that I don't make many high abv beers lately and also no fruit.

 

[McMullan]

Take a look at this article. It might give you some idea of your yeast's shelf life.

http://www.woodlandbrew.com/2012/12/refrigeration-effects-on-yeast-viability.html

I'm not sure what we gain from that very limited blog post. How do we apply it, with more assumptions?

 

[Off Balance Brewing]

I'm not sure what we gain from that very limited blog post. How do we apply it, with more assumptions?

I read it as a counterpoint to the standard 50 percent decay a month that comes up all the time. Limited blog post makes it seems very strain dependent. I would love a more detailed source but haven't seen one yet.

 

[McMullan]

There is no standard. One of the problems with mysterious online calculators assuming there is one. Ditto assumptions poorly presented in blogs. How well harvested yeast slurry stores depends on several factors. And it can only be determined empirically for a given yeast strain and brewer. Trying to measure yeast viability without a sophisticated lab instrument (a flow cytometer) is notoriously problematic and doesn't capture any measure of yeast vitality. A slurry might have high viability with low vitality whereas another has relatively low viability but very high vitality. Are unreliable viability measures alone of much value? Fact is, freshly prepped or harvested yeast are more likely to have high viability and high vitality. If that's what you're looking for. If a simple surrogate measure of yeast vitality is used, e.g. time for a standardised wort to reach 4% ABV, declines can be observed within a few days of storage following harvesting. Again, it's a downhill process, biologically. The yeast are starving in a closed system where scare resources are declining. Like any famine, it doesn't promote survivability.

 

[beerfactory]

I use the simple yeast harvest approach... I've never had an issue with direct pitching about 8 to 10 oz of slurry except longer lag... 24 to 48 hour slurry....

This has been my experience as well. Brewing monthly, it doesn't save me much money to repitch. But I enjoy doing it and the beer tastes good to me.

 

[px9798]

Yes I know a starter will reduce lag

Yes I've heard slurries older than 2 weeks should have a stater.

I use the simple yeast harvest approach but I typically rotate 2 strains and brew monthly. So my slurries are usually 2 or 3 months old. I've never had an issue with direct pitching about 8 to 10 oz of slurry except longer lag. I pitch more due to longer storage.

My question is why is this not the case with fresh liquid pitches? Why can omega for example have a 5 month shelf life for a 1.060 beer pitch and usually fires 12 to 24 hours versus my 24 to 48 hour slurry? Are they packing the fresh count for 5 months of decay? I thought I've heard 50 percent cell count drop over 4 weeks. Are they really providing over a billion cell count fresh?

Or is there some other change I can do to my storage method to reduce lag?

As mentioned in many of these posts, the "storeagability" of different strains varies. One rule is the colder the better, short of freezing, which will damage cells. Viability, the number of live cells in a given number of cells pitched, is one crucial factor. This can be checked by homebrewers with the purchase of a decent microscope, a hemocytometer and some dye. The procedure is basic highs school level science lab stuff, but hardly necessary.
One thing I have not read in the posts, coulda missed it, is any mention of oxygenation. One of the biggest drivers of yeast division and therefore lag or lack thereof is wort oxygen levels. I have pitched a couple of smack packs, both lager and ale into my 1.5 bbl batches with the yeast taking off within a day. While in practice, I am drastically underpitching, my lag is only slightly longer than I see when pitching FRESH slurry. Estimate pitching rate for 1.5 bbl is a liter of thick slurry! A carbonation stone in the fermenter or in line downstream of the chiller with some pure O2 or even just air through a 5 micron filter will do the trick. Even a carboy with alot of vigorous shaking should do the trick.
Though I have not purchased a hemocytometer and scope, if I were planning to turn yeast around from one batch to the next repeatedly I would. When I was a professional brewer, we tracked viability of the yeast on every batch and found that viability dropped over successive re-use. Every dozen batches or so we would have to start a new "batch" Literally pulling a health colony from an agar plate and bringing it up in successive starter volumes from a few oz. to over 50 gallons. For all kinds of reasons, yeast viability drops off with age and over successive batches made with the same batch of yeast. So freshness, viability and cold wort oxygenation/aeration are the key factors.

 

[Off Balance Brewing]

As mentioned in many of these posts, the "storeagability" of different strains varies. One rule is the colder the better, short of freezing, which will damage cells. Viability, the number of live cells in a given number of cells pitched, is one crucial factor. This can be checked by homebrewers with the purchase of a decent microscope, a hemocytometer and some dye. The procedure is basic highs school level science lab stuff, but hardly necessary.
One thing I have not read in the posts, coulda missed it, is any mention of oxygenation. One of the biggest drivers of yeast division and therefore lag or lack thereof is wort oxygen levels. I have pitched a couple of smack packs, both lager and ale into my 1.5 bbl batches with the yeast taking off within a day. While in practice, I am drastically underpitching, my lag is only slightly longer than I see when pitching FRESH slurry. Estimate pitching rate for 1.5 bbl is a liter of thick slurry! A carbonation stone in the fermenter or in line downstream of the chiller with some pure O2 or even just air through a 5 micron filter will do the trick. Even a carboy with alot of vigorous shaking should do the trick.
Though I have not purchased a hemocytometer and scope, if I were planning to turn yeast around from one batch to the next repeatedly I would. When I was a professional brewer, we tracked viability of the yeast on every batch and found that viability dropped over successive re-use. Every dozen batches or so we would have to start a new "batch" Literally pulling a health colony from an agar plate and bringing it up in successive starter volumes from a few oz. to over 50 gallons. For all kinds of reasons, yeast viability drops off with age and over successive batches made with the same batch of yeast. So freshness, viability and cold wort oxygenation/aeration are the key factors.

Thanks PX. I typically move my beer to the fermenter by pump with the fill hose about 3 ft up to splash oxygenate. I've assumed that is better than shaking but I'll try adding a shaking step after I close up the fermenter also.

Slurry storage in beer should be cold with low oxygen right?

I usually only repitch 3 or 4 times before move to another strain so I don't think I'm generationally straining them.

 

[hottpeper13]

My last brew I did a primary transfer to keg then pitched slurry onto a 1.094 RIS wort in the same morning and had to put a blow off on it before bed time. It was like zero lag time. OK, so it was Notty and the IPA it was fermenting was 1.060.
The IPA was in primary for 4 weeks,so the yeast slurry was basically 3 weeks in "storage",at 64*. I don't see the difference.

 

[px9798]

Thanks PX. I typically move my beer to the fermenter by pump with the fill hose about 3 ft up to splash oxygenate. I've assumed that is better than shaking but I'll try adding a shaking step after I close up the fermenter also.

Slurry storage in beer should be cold with low oxygen right?

I usually only repitch 3 or 4 times before move to another strain so I don't think I'm generationally straining them.

Correct, cold storage with low oxygen is the best storage method, splashing and shaking are better than nothing. The nice thing about a 5 micron sintered stainless "stone" is that the diffusion is greater, increasing absorption, or the amount actually in solution. DO NOT aerate if your wort is still hot or warm, hot side wort aeration is to be avoided at all costs, cardboard and other off flavors will result.
From Amazon: (2 Set) FERRODAY 0.5 Micron Diffusion Stone Stainless Steel Aeration Stone Carbonating Stone with 1/4" Barb for Homebrew Wine Beer Soda Air Stone 0.5 Micron + 20 Inch Silicone Hose

 

[px9798]

Correct, cold storage with low oxygen is the best storage method, splashing and shaking are better than nothing. The nice thing about a 5 micron sintered stainless "stone" is that the diffusion is greater, increasing absorption, or the amount actually in solution. DO NOT aerate if your wort is still hot or warm, hot side wort aeration is to be avoided at all costs, cardboard and other off flavors will result.
From Amazon: (2 Set) FERRODAY 0.5 Micron Diffusion Stone Stainless Steel Aeration Stone Carbonating Stone with 1/4" Barb for Homebrew Wine Beer Soda Air Stone 0.5 Micron + 20 Inch Silicone Hose

Sorry 0.5 micron...

 

[px9798]

Sorry 0.5 micron...

and air should be filtered to 5 micron or better, oxygen if from a clean cylinder should not require filtration, but I do so regardless, as I tend to use O2 from a oxy acetylene rig and I can't vouch for the cylinder's condition. I mostly use filtered air from a standard pancake compressor and through a coarse air filter then through a 5 micron filter. Never had an issue with contamination. In practice any unfiltered air from splashing or shaking contains microbes. But with good pitching amounts, brewers yeast is "killer yeast" and tends to put down any competition...

 

[RM-MN]

Every dozen batches or so we would have to start a new "batch"

Wait! I've been seeing that one should not go past about 5 batches on a yeast because of mutations. 12 has to be too many, right?

 

[Off Balance Brewing]

Wait! I've been seeing that one should not go past about 5 batches on a yeast because of mutations. 12 has to be too many, right?

Definition of a "house strain"?

Says checking viability each batch

 

[RM-MN]

Definition of a "house strain"?

Says checking viability each batch

How can you have a "house strain" if it is mutating? Checking viability is not the same as checking for mutations. How do you even check for mutations?

My question was about the conventional wisdom that one shouldn't go more than 5 generations because of the mutations. Was that conventional wisdom wrong or were there sever mutations occurring that the brewer was just ignoring?

 

[Off Balance Brewing]

I'm also interested in the 5 repitch wisdom.

I always assume a house strain could be achieved by yeast blends or mutations that have been a result of your specific brewing process. Like yeast darwinism for your repeated brews.

 

[McMullan]

Some breweries in the UK have been serially repitching their brewery yeast(s) for several decades. They brew twice a week and store harvested slurry for the shortest period thus selecting for fermentation traits, not storage traits. If you're a brewer, you want to pitch fresh yeast which express fermentation traits, not storability traits, which is a different strain altogether. If you're following poor yeast management practices, your brewery yeast is going to evolve away from its former glory and you'll have to start over with a fresh supply of yeast. Perhaps this says a lot about the practices of many commercial breweries these days?

 

[px9798]

Wait! I've been seeing that one should not go past about 5 batches on a yeast because of mutations. 12 has to be too many, right?

The experience I related was in a regional brewery with fine control of the fermentation parameters, rapid turnaround, cylindroconical fermenters in which we were able to crop yeast at the optimal time glycol jacketed yeast storage vessels and so on, so we were able to get twelve on average before we reverted back to the control culture due to viability and potential mutations. We had a lab that we monitored things that we homebrewers don't need to worry about and could spot issues before product was affected. In my homebrewing, I seldom harvest yeast for another batch period and when I do it's typically a one generation deal, as I typically do a variety of styles and alternate between Lagers and Ales of different types, so yeasts are constantly being changed.

 

[McMullan]

The stressful environments at macro scale, which are a form of poor yeast management practice, especially if high gravity wort is used, don't select for desirable fermentation traits either.

 

[Spivey24]

So is there a “good” way to repitch? I should go back to just overbuilding starters and saving half, but sometimes I am stuck with a repitch.

So normally I do fermentation for 2-3 weeks, cold crash, then transfer and collect the slurry, add to large mason jar with some beer on top and put in fridge. Some weeks later, I pull it out, add it to 1.037 wort and put it on the stir plate for 1 day. Cold crash it in fridge, decant, warm slightly and pitch.

 

[McMullan]

So is there a “good” way to repitch?

Fresher the better. Fermentation doesn't normally take 2-3 weeks. If you managed to brew weekly you could easily repitch top quality yeast batch to batch.

 

[cmac62]

So is there a “good” way to repitch? I should go back to just overbuilding starters and saving half, but sometimes I am stuck with a repitch.

So normally I do fermentation for 2-3 weeks, cold crash, then transfer and collect the slurry, add to large mason jar with some beer on top and put in fridge. Some weeks later, I pull it out, add it to 1.037 wort and put it on the stir plate for 1 day. Cold crash it in fridge, decant, warm slightly and pitch.

If you are enjoying your beer keep doing it. I usually will pull my decanted started out of the fridge at the beginning of the brew day and let it warm that way. My guess is thermal shock is more of a concern than anything at this level. Of course I may be totally wrong also.

 

[Spivey24]

So is there a “good” way to repitch? I should go back to just overbuilding starters and saving half, but sometimes I am stuck with a repitch.

So normally I do fermentation for 2-3 weeks, cold crash, then transfer and collect the slurry, add to large mason jar with some beer on top and put in fridge. Some weeks later, I pull it out, add it to 1.037 wort and put it on the stir plate for 1 day. Cold crash it in fridge, decant, warm slightly and pitch.

So I just did this with a lager yeast wlp838, and 1.5 days later barely a sign of anything happening. 1.050 starting gravity. Tiny bubbles on the surface but nothing registering on the Tilt yet. I think I will stick with overbuilding starters and saving half. Maybe if it happens to work out that I can go from one finished fermenter straight to the new one for something that fermented in under 2 weeks.

 

[beerfactory]

Some anecdotal notes on a slurry lag time experience with simple yeast storage from this weekend.

I brewed a blonde ale, yesterday. Finished brewing ~2pm.

A quart jar filled with 2nd generation Nottingham slurry harvested on 3/5 was taken from the fridge and set in a dark spot on my kitchen counter ~11am. My house was at 70F.

I collect slurry via 5oz long handled stainless ladle from the bottom of my kegmenter post fermentation. I generally pitch and rack to a keg after 2 weeks and then collect slurry.

It was 1047PM before my kegmenter came down to 67F in my fermentation fridge. I had ran 10 gallons through an immersion chiller to knock the temp down a bit, racked into the kegmenter and put it in the fridge to continue cooling. 1047PM is when I pitched by pouring off most of the liquid, swirling the yeast into suspension a bit and pitching straight in.

The temp was set to 64F plus 2/minus 0 with an inkbird probe taped to the kegmenter w/ a couple layers of masking tape.

I woke up at 627AM and blowoff was bubbling @ ~ 2 bubbles per second and the probe temp read 64F.

 

[eric19312]

Some breweries in the UK have been serially repitching their brewery yeast(s) for several decades. They brew twice a week and store harvested slurry for the shortest period thus selecting for fermentation traits, not storage traits. If you're a brewer, you want to pitch fresh yeast which express fermentation traits, not storability traits, which is a different strain altogether. If you're following poor yeast management practices, your brewery yeast is going to evolve away from its former glory and you'll have to start over with a fresh supply of yeast. Perhaps this says a lot about the practices of many commercial breweries these days?

I believe most of these UK breweries use or at least historically used top cropping at peak of fermentation for harvesting as part of the selection bias pressure. Avoiding collecting dead yeast and non yeast trub, and avoiding selections for early or late flocculating yeast.

 

[Spivey24]

Some anecdotal notes on a slurry lag time experience with simple yeast storage from this weekend.

I brewed a blonde ale, yesterday. Finished brewing ~2pm.

A quart jar filled with 2nd generation Nottingham slurry harvested on 3/5 was taken from the fridge and set in a dark spot on my kitchen counter ~11am. My house was at 70F.

I collect slurry via 5oz long handled stainless ladle from the bottom of my kegmenter post fermentation. I generally pitch and rack to a keg after 2 weeks and then collect slurry.

It was 1047PM before my kegmenter came down to 67F in my fermentation fridge. I had ran 10 gallons through an immersion chiller to knock the temp down a bit, racked into the kegmenter and put it in the fridge to continue cooling. 1047PM is when I pitched by pouring off most of the liquid, swirling the yeast into suspension a bit and pitching straight in.

The temp was set to 64F plus 2/minus 0 with an inkbird probe taped to the kegmenter w/ a couple layers of masking tape.

I woke up at 627AM and blowoff was bubbling @ ~ 2 bubbles per second and the probe temp read 64F.

Maybe notty is better suited for this. But I guess that is the problem - too many variables. The yeast strain, length of storage, previous brew strength, etc. if you are a brewery doing the same brew on the same schedule with the same yeast, you can find a repeatable solution. But homebrewing, forget it for me.

 

[Nubiwan]

Do a search for yeast viability. There is more hype about starters than there is truth. For instance, people say you have to have a large starter for a lager since it will be fermented at a cool temp. Gordon Strong, a 4 time Ninkasi award winner, has said that the often make a batch of lager and pitches a single smack pack. Wouldn't a Ninkasi award winner know what good beer is? Wouldn't he try to make it the best possible for his own consumption? What does he do to make a single pack ferment his lager properly while other people argue that you can only do that by making a starter and then step it up to a bigger starter?

My question would be, what detriment, if any, does lag time of 48 hours, or pitching old slurry have, over a fresh yeast that kicks off within hours? My intuition/experience tells me it might not be measurable at home brew scale.

 

[McMullan]

My question would be, what detriment, if any, does lag time of 48 hours, or pitching old slurry have, over a fresh yeast that kicks off within hours?

https://www.homebrewtalk.com/threads/pitching-slurry.696361/post-9296881

 

[RM-MN]

My question would be, what detriment, if any, does lag time of 48 hours, or pitching old slurry have, over a fresh yeast that kicks off within hours? My intuition/experience tells me it might not be measurable at home brew scale.

The longer the lag, the more chance bacteria have to propagate. Presuming that all the bacteria are dead after the boil it will only be bacteria that falls from the air and that will take time to build up a large population. The introduction of a large amount of yeast will counteract that.

 

[odie]

Wait! I've been seeing that one should not go past about 5 batches on a yeast because of mutations. 12 has to be too many, right?

there is no standard. repitch until you get a bad beer or the yeast slurry sells funky. Yeast strains have been propagated for centuries.

MK1 sniff test before repitching. If the slurry smells bad it's probably bad. If it smelled fine but the beer turns out bad anyway, well toss that new slurry (and beer) out too and start with a fresh pack of yeast. At some point your sanitation probably got sloppy.