Isolated Yeast (Tree House): How to Identify and Characterize?

[TheHairyHop]

I would consider light spice and pepper together with fruit to be very much a saison flavor profile

 

[melville]

I would consider light spice and pepper together with fruit to be very much a saison flavor profile

This would make a mediocre saison I would think. The T-58 is sweet, minus any signs of hay or rustic notes, or lemony/bright/tart highlights.

 

[melville]

Did you get anything out of WB-06? I thought it was really neutral with a slight tang.

Making one for WB-06 tonight. I can't remember — did you notice a difference in mouthfeel between the 3?

 

[isomerization]

Making one for WB-06 tonight. I can't remember — did you notice a difference in mouthfeel between the 3?

They were all quite dry (as to be expected given the wort composition). I would say if anything the T-58 had the edge, but I could also chalk that up to the fact that the other two had such clean flavor profiles (and confirmation bias).

 

[overthebarsbrewing]

I don't have the gel images on hand, but I just ran an experiment comparing the ability of S-04 and T-58 to (separately) grow in the presence of CBC-1 (all yeast isolates from TH, not commercial samples).

I tested 8 colonies each from saturated, mixed cultures where an equal amount of saturated slurry was used to incubate YPD media. The S-04 v CBC-1 culture was all CBC-1. The T-58 v CBC-1 culture was 6:2 in favor of CBC-1. Now this isn't what I'd call a rigorous experiment (should test 30+ colonies), but the fact that T-58 colonies showed up at all, raises a question, are there commonly used Sacc strains that are resistant to the toxin made by CBC-1? Probably a question for Fermentis...

Amazing science and experimentation going on in this thread! Major kudos to all involved. I have clinical & molecular micro training and experience so I’m pretty geeked out by all this work so far!

I’ve read through this thread from start to finish a couple times now to try and wrap my head around everything that’s been done and discussed so I can try to add to the discussions/experimentations.

WRT your co-culture experiment results…how long did you grow CBC-1 together with T-58 and S-04? I’m trying to figure out what fermentation scenarios could cause the observations that you got from screening TH can samples in the context of the results from your experiment.

Remind me again approximately how old those cans were? And were they kept refrigerated the whole time before you sampled? Or were they shipped out (and potentially exposed to temps that could trigger re-fermentation?)

More specifically, I’m trying to figure out ways that would explain how CBC-1 and S-04 seem to be the predominant colonies that you isolated from your TH can samples. All total, these 2 strains represented ~80% of all colonies tested.

If CBC-1 is being used as the conditioning/carbonating strain (currently most likely hypothesis), I’m wondering why there’s still so much S-04 around given that: (1) it flocs well (supposedly), and (2) it seemed to get killed by CBC-1 in your experiment.

Thoughts?

 

[overthebarsbrewing]

All 3 beakers are the same depth, so don't let the varying liquid heights fool you.

Fermentis describes S-04 as "English ale yeast selected for its fast fermentation character and its ability to form a compact sediment at the end of fermentation, helping to improve beer clarity"

So how does it end up the most turbid of the 3 starters?

Yeast are fickle...

 

[overthebarsbrewing]

I don't have the gel images on hand, but I just ran an experiment comparing the ability of S-04 and T-58 to (separately) grow in the presence of CBC-1 (all yeast isolates from TH, not commercial samples).

I tested 8 colonies each from saturated, mixed cultures where an equal amount of saturated slurry was used to incubate YPD media. The S-04 v CBC-1 culture was all CBC-1. The T-58 v CBC-1 culture was 6:2 in favor of CBC-1. Now this isn't what I'd call a rigorous experiment (should test 30+ colonies), but the fact that T-58 colonies showed up at all, raises a question, are there commonly used Sacc strains that are resistant to the toxin made by CBC-1? Probably a question for Fermentis...

Amazing science and experimentation going on in this thread! Major kudos to all involved. I have clinical & molecular micro training and experience so I’m pretty geeked out by all this work so far. I’ve read through this thread from start to finish a couple times now to try and wrap my head around everything that’s been done and discussed so I can try to add to the discussions/experimentations.

WRT your co-culture experiment results…how long did you grow CBC-1 together with T-58 and S-04? I’m trying to figure out what fermentation scenarios could cause the observations that you got from screening TH can samples in the context of the results from your experiment. Remind me again approximately how old those cans were? And were they kept refrigerated the whole time before you sampled? Or were they shipped out (and potentially exposed to temps that could trigger re-fermentation?)

More specifically, I’m trying to figure out ways that would explain how CBC-1 and S-04 seem to be the predominant colonies that you isolated from your TH can samples. All total, these 2 strains represented ~80% of all colonies tested. If CBC-1 is being used as the conditioning/carbonating strain (currently most likely hypothesis), I’m wondering why there’s still so much S-04 around given that: (1) it flocs well (supposedly), and (2) it seemed to get killed by CBC-1 in your experiment.

Thoughts?

 

[overthebarsbrewing]

Amazing science and experimentation going on in this thread! Major kudos to all involved. I have clinical & molecular micro training and experience so I’m pretty geeked out by all this work so far. I’ve read through this thread from start to finish a couple times now to try and wrap my head around everything that’s been done and discussed so I can try to add to the discussions/experimentations.

@isomerization - WRT your co-culture experiment results…how long did you grow CBC-1 together with T-58 and S-04? I’m trying to figure out what fermentation scenarios could cause the observations that you got from screening TH can samples in the context of the results from your experiment. Remind me again approximately how old those cans were? And were they kept refrigerated the whole time before you sampled? Or were they shipped out (and potentially exposed to temps that could trigger re-fermentation?)

More specifically, I’m trying to figure out ways that would explain how CBC-1 and S-04 seem to be the predominant colonies that you isolated from your TH can samples. All total, these 2 strains represented ~80% of all colonies tested. If CBC-1 is being used as the conditioning/carbonating strain (currently most likely hypothesis), I’m wondering why there’s still so much S-04 around given that: (1) it flocs well (supposedly), and (2) it seemed to get killed by CBC-1 in your experiment.

Thoughts?

 

[isomerization]

Fermentis describes S-04 as "English ale yeast selected for its fast fermentation character and its ability to form a compact sediment at the end of fermentation, helping to improve beer clarity"

So how does it end up the most turbid of the 3 starters?

Yeast are fickle...

These are after a 48hr cold crash in my fridge too. The S-04 culture floccs like a beast, within 15 seconds of removal from the orbital shaker, the large majority of the yeast are already piled up at the bottom of the flask. Why the culture supernatant is that hazy though, not sure there...

Amazing science and experimentation going on in this thread! Major kudos to all involved. I have clinical & molecular micro training and experience so I’m pretty geeked out by all this work so far. I’ve read through this thread from start to finish a couple times now to try and wrap my head around everything that’s been done and discussed so I can try to add to the discussions/experimentations.

@isomerization - WRT your co-culture experiment results…how long did you grow CBC-1 together with T-58 and S-04? I’m trying to figure out what fermentation scenarios could cause the observations that you got from screening TH can samples in the context of the results from your experiment. Remind me again approximately how old those cans were? And were they kept refrigerated the whole time before you sampled? Or were they shipped out (and potentially exposed to temps that could trigger re-fermentation?)

More specifically, I’m trying to figure out ways that would explain how CBC-1 and S-04 seem to be the predominant colonies that you isolated from your TH can samples. All total, these 2 strains represented ~80% of all colonies tested. If CBC-1 is being used as the conditioning/carbonating strain (currently most likely hypothesis), I’m wondering why there’s still so much S-04 around given that: (1) it flocs well (supposedly), and (2) it seemed to get killed by CBC-1 in your experiment.

Thoughts?

Thanks, and I'm glad you've enjoyed the thread! I have learned so much from these discussions regarding fermentation process, its been very rewarding.

RE your questions. I live in KS, so all cans were shipped, and I don't think any of them were younger than 2 weeks old when we sampled/harvested. The best explanation I can give is that I didn't know what I was doing during the large majority of this project Several times I let the yeast dregs grow up over the weekend in a small amount of media (see, I think Green, where almost everything was a red square). I cannot claim to be a yeast biologist, but I believe the toxin that CBC-1 creates only inhibits growth (static) versus lysis/death (cidal). So, when the dregs are streaked out and grown up as isogenic cultures, the sensitive yeast (e.g. S-04) can grow again.

So, the working hypothesis (which is reflected in the yeast %s being used by most of us experimenting) is that the majority of the yeast used in primary is S-04, with T-58 and WB-06 providing support. CBC-1 is then used during conditioning. This would, in theory, get you to the 80% threshold that my (non-significant) sampling rates saw.

Would you agree with that analysis?

 

[bierhaus15]

Anyone consider that CBC-1 is a Lallemand product and is not available via BSG, whom carries Fermentis. Would be unlikely you'd order all your ingredients from one supplier and then have to order a single bottle conditioning yeast from another.

 

[overthebarsbrewing]

Thanks for the additional info! I was (and still am) doing a bit of digging and reading on the yeast toxin(s). Everything I'm finding seems to point to them being truly cidal...

For example, this nice review article (http://onlinelibrary.wiley.com/doi/10.1002/j.2050-0416.2005.tb00221.x/full) describes:

"S. cerevisiae produces three types of killer factors: K1, K2 and K28. K1 and K2 act as ionophores and K28 inhibits DNA synthesis in the sensitive cells"

then goes on to state:

"The interaction between Saccharomyces cerevisiae killer yeast and sensitive yeast requires a specific binding of the zymocin to glucan moieties present in the sensitive yeast cell wall. This induces plasma membrane damage in the sensitive yeast cell"


Anything that pokes holes in plasma membranes is almost always going to be a cidal compound. They are an absolutely crucial part of the cell.

These are pretty potent compounds too, it seems. from that same article:

"Philliskirk and Young studied the effects of killer yeasts on fermentations and demonstrated that some brewing yeasts could be susceptible to concentrations of killer yeast as low as 0.01%."



WRT info in your reply:

These are after a 48hr cold crash in my fridge too. The S-04 culture floccs like a beast, within 15 seconds of removal from the orbital shaker, the large majority of the yeast are already piled up at the bottom of the flask. Why the culture supernatant is that hazy though, not sure there...

I wonder if this could just be related to proteins, sugars, etc. that could remain post-ferment that S-04 produces in higher quantities than the other 2 yeasts? Chilling it precipitates them out (chill haze?) and even warming to room temperature isn't enough to re-dissolve them?

all cans were shipped, and I don't think any of them were younger than 2 weeks old when we sampled/harvested. The best explanation I can give is that I didn't know what I was doing during the large majority of this project Several times I let the yeast dregs grow up over the weekend in a small amount of media (see, I think Green, where almost everything was a red square). I cannot claim to be a yeast biologist, but I believe the toxin that CBC-1 creates only inhibits growth (static) versus lysis/death (cidal). So, when the dregs are streaked out and grown up as isogenic cultures, the sensitive yeast (e.g. S-04) can grow again.

Hmmm...lots of stuff going on here that could make the ratios that you got not truly represent the ratios in the immediately-packaged beers (but you all have already pretty much acknowledged that the ratios from the DNA experiments are not something you view as highly accurate. But the fact that you got them and they match well with commercially available yeasts means that they aren't all in there by accident!

So, the working hypothesis (which is reflected in the yeast %s being used by most of us experimenting) is that the majority of the yeast used in primary is S-04, with T-58 and WB-06 providing support. CBC-1 is then used during conditioning. This would, in theory, get you to the 80% threshold that my (non-significant) sampling rates saw.

Would you agree with that analysis?

I think I agree that S-04 is one of the primary ferment yeasts. For a variety of reasons already discussed. It also may continue to show up in pretty high quantities even in the presence of CBC-1 perhaps because it may be partially tolerant to the CBC-1 toxins? Might be interesting to repeat your co-culture experiment and simulate conditions when CBC-2 would be added---specifically, I'd bet the ratio of S-04 cells to CBC-1 is pretty high. Maybe do a 90% S-04 / 10% CBC-1 culture and see what happens after 48h or so? Perhaps more S-04 will survive?

Cheers!

 

[couchsending]

Anyone consider that CBC-1 is a Lallemand product and is not available via BSG, whom carries Fermentis. Would be unlikely you'd order all your ingredients from one supplier and then have to order a single bottle conditioning yeast from another.

Weyerman is BSG though right? Just chuck some yeast in with that truck load of Pilsner.

 

[couchsending]

This would make a mediocre saison I would think. The T-58 is sweet, minus any signs of hay or rustic notes, or lemony/bright/tart highlights.

Some useful info here on T-58 from probrewer.

http://discussions.probrewer.com/showthread.php?62136-recommends-for-a-dry-yeast-for-a-Belgian-Tripel

If you're tasting a starter it would be sweeter and have more body as it struggles with Maltotriose. Fermentis sheet gives a high residual sugar amount for this reason. Also a good reason for it to be used as a bottle conditioner, less likely for bottle bombs.

 

[melville]

Anyone consider that CBC-1 is a Lallemand product and is not available via BSG, whom carries Fermentis. Would be unlikely you'd order all your ingredients from one supplier and then have to order a single bottle conditioning yeast from another.

My assumption is that CBC-1 will look like fermentis' F2, but we just can't get ahold of F2 in homebrew sized sachets at the moment.

 

[isomerization]

Anyone consider that CBC-1 is a Lallemand product and is not available via BSG, whom carries Fermentis. Would be unlikely you'd order all your ingredients from one supplier and then have to order a single bottle conditioning yeast from another.

I would bet several rounds of beers that F-2 and CBC-1 are basically the same thing. I couldn't find a US-based source for F-2 though.

 

[isomerization]

Thanks for the additional info! I was (and still am) doing a bit of digging and reading on the yeast toxin(s). Everything I'm finding seems to point to them being truly cidal...

For example, this nice review article (http://onlinelibrary.wiley.com/doi/10.1002/j.2050-0416.2005.tb00221.x/full) describes:

"S. cerevisiae produces three types of killer factors: K1, K2 and K28. K1 and K2 act as ionophores and K28 inhibits DNA synthesis in the sensitive cells"

then goes on to state:

"The interaction between Saccharomyces cerevisiae killer yeast and sensitive yeast requires a specific binding of the zymocin to glucan moieties present in the sensitive yeast cell wall. This induces plasma membrane damage in the sensitive yeast cell"


Anything that pokes holes in plasma membranes is almost always going to be a cidal compound. They are an absolutely crucial part of the cell.

These are pretty potent compounds too, it seems. from that same article:

"Philliskirk and Young studied the effects of killer yeasts on fermentations and demonstrated that some brewing yeasts could be susceptible to concentrations of killer yeast as low as 0.01%."

That all sounds reasonable to me, could be something to do with its use as a conditioning strain rather than in primary then?

"The activity of the toxin is greatest during the log phase of growth, and decays during the stationary phase of fermentation [9]."

I'm not sure whether that statement is suggesting that the susceptible strains might not be killed if metabolic activity is low, or if the toxin's themselves are down-regulated during periods of metabolic activity. Either way, we are just guessing here!

 

[isomerization]

Some useful info here on T-58 from probrewer.

http://discussions.probrewer.com/sh...commends-for-a-dry-yeast-for-a-Belgian-Tripel

If you're tasting a starter it would be sweeter and have more body as it struggles with Maltotriose. Fermentis sheet gives a high residual sugar amount for this reason. Also a good reason for it to be used as a bottle conditioner, less likely for bottle bombs.

From that thread: "I've found an overwhelming isoamyl acetate character at anything above 68". Seems opposite of what has been discussed in this thread! I do wonder if yeast blends can more easily deal with these off-flavors and create a more well rounded ester profile (which might not be desirable if you're brewing a hefe/wit/etc).

 

[melville]

From that thread: "I've found an overwhelming isoamyl acetate character at anything above 68". Seems opposite of what has been discussed in this thread! I do wonder if yeast blends can more easily deal with these off-flavors and create a more well rounded ester profile (which might not be desirable if you're brewing a hefe/wit/etc).

Three things we sort of know:

1. TH isn't fermenting over 70F.
2. Th isn't making banana bombs...
3. ...even though TH is using two yeasts known for putting out banana — albeit less so than liquid alternatives of hefe and belgian strains.

 

[overthebarsbrewing]

That all sounds reasonable to me, could be something to do with its use as a conditioning strain rather than in primary then?

"The activity of the toxin is greatest during the log phase of growth, and decays during the stationary phase of fermentation [9]."

I'm not sure whether that statement is suggesting that the susceptible strains might not be killed if metabolic activity is low, or if the toxin's themselves are down-regulated during periods of metabolic activity. Either way, we are just guessing here!

Agree that statement is ambiguous. And I'm not sure of the original article where they did those experiments.

Some interesting & relevant observations on killer strains from one of the original brewery-focused articles from 1973 (!!!)

http://onlinelibrary.wiley.com/doi/10.1002/j.2050-0416.1973.tb03515.x/pdf

1--Killing activity happens fast (within 24h of co-incubation)
2--Killing is influenced by the % inoculated at the start of a co-incubation:

Testing 50/50 and 10/90 mixes of killer/brewery yeasts resulted in complete kill of the brewery yeast within 24h of incubation at 28*C. "Some growth" of the brewery yeast occurred with a mix of 2%/98% killer/brewery yeast; table from the article suggests a mix of ~70%/30% viable killer/brewery yeast at the end of incubation.

In a test fermentation (2L of hopped 1.038 OG malt wort), "marked killer effect resulted only when the inoculum of killer strain was greater than 5%"
​

Application to us:

Even more strongly supports working hypothesis that CBC-1 is used as a carbonating/conditioning strain. Given the relatively small amount of cells that need to be added, it's probably not nearly enough to kill off all the previous yeast cells that were already present in the fermented beer. Thus the ability to grow/detect S-04, T-58, & WB-06. The fact that growing the dregs in fresh media results in a shift towards CBC-1 predominant samples fits nicely with all this too.

 

[stonebrewer]

Anyone consider that CBC-1 is a Lallemand product and is not available via BSG, whom carries Fermentis. Would be unlikely you'd order all your ingredients from one supplier and then have to order a single bottle conditioning yeast from another.

Few breweries are going to limit themselves to a subset of ingredients they need, and with two suppliers they can get the majority of products out there they would need to make any beer. I have a relationship with a local brewery and they order every week from the two big US suppliers, and I don't think that is uncommon. </Shrug>

 

[mikeroesoft]

I have been trying to keep up with this most excellent thread and am currently about halfway through, so excuse me if this has been mentioned but I just came home and grabbed a blonde I had brewed with 1968. Its only been in the keg a week and I have noticed the beer become slightly drier and has lost some of the melon-y ester I was able to pickup when I initially tried it. This got me thinking about previous beers (Specifically IPAs) I have brewed and I have found that the beers drop off for better or worse, in the first couple weeks. I believe that even though beer is in the fridge, the yeast continues to 'condition' the beer. I am wondering if the CBC-1 yeast not only carbonates but kills off the other yeast strains in the beer and prevents this type of conditioning/ester degradation/hop oil metabolisation.

 

[isomerization]

Agree that statement is ambiguous. And I'm not sure of the original article where they did those experiments.

Some interesting & relevant observations on killer strains from one of the original brewery-focused articles from 1973 (!!!)

http://onlinelibrary.wiley.com/doi/10.1002/j.2050-0416.1973.tb03515.x/pdf

1--Killing activity happens fast (within 24h of co-incubation)
2--Killing is influenced by the % inoculated at the start of a co-incubation:

Testing 50/50 and 10/90 mixes of killer/brewery yeasts resulted in complete kill of the brewery yeast within 24h of incubation at 28*C. "Some growth" of the brewery yeast occurred with a mix of 2%/98% killer/brewery yeast; table from the article suggests a mix of ~70%/30% viable killer/brewery yeast at the end of incubation.

In a test fermentation (2L of hopped 1.038 OG malt wort), "marked killer effect resulted only when the inoculum of killer strain was greater than 5%"
​

Application to us:

Even more strongly supports working hypothesis that CBC-1 is used as a carbonating/conditioning strain. Given the relatively small amount of cells that need to be added, it's probably not nearly enough to kill off all the previous yeast cells that were already present in the fermented beer. Thus the ability to grow/detect S-04, T-58, & WB-06. The fact that growing the dregs in fresh media results in a shift towards CBC-1 predominant samples fits nicely with all this too.

Always nice to see data supporting the existing hypothesis

 

[Sbe2]

So I have a party that I am providing a keg of NEIPA for. The party is on 8/26. I was wondering what the turnaround is for you all? I plan on brewing tomorrow 8/06.

I usually ferment with 1318, and am debating on whether to condition with cbc-1. How long does it take to condition 5 gallons? How much do you use (11g)?

My next batch will be more along the lines of what you all have been brewing the past few weeks, simple grain bill, a combo of s04, wb06, t58 and hopefully I can contribute to this thread.

 

[isomerization]

So I have a party that I am providing a keg of NEIPA for. The party is on 8/26. I was wondering what the turnaround is for you all? I plan on brewing tomorrow 8/06.

I usually ferment with 1318, and am debating on whether to condition with cbc-1. How long does it take to condition 5 gallons? How much do you use (11g)?

My next batch will be more along the lines of what you all have been brewing the past few weeks, simple grain bill, a combo of s04, wb06, t58 and hopefully I can contribute to this thread.

I have made several NE IPA with 1318 and usually ferment around 72F, this yeast is a beast! You can dry hop 48 hr after pitching and prob be ready to keg by day 7 easy (if keg hopping, if not add 2-3 days). I wouldn't recommend keg conditioning (new variable, takes at least 5 days). You can rack to the keg, place in kegerator for 24 hr, hit with 40 psi for 24 hr, drop to serve pressure, dump a pint or two and start drinking. The extra week in your timeline means it will be approaching peak quality too, so that's nice

My plan with the CBC-1 is to use 2g dry after a cold crash to try and remove as much of the prior yeast as possible.

 

[couchsending]

For a quin turn and burn 1968 or 002 has worked great for me even at lower temps. Just overpitch a little bit, pitch at 62, ferment at 64 then let rise to 68 at the end for D-rest. The yeast floccs so hard it helps to filter everything and it's easier to get cleaner tasting beer, quickly IMHO. I had one go from 1.060 to 1.012 in 3 days at those lower temps (152 mash). I was inspired to use 002 more after listening to a podcast where the Creature Comfort guys talk about being able to get Tropicalia out of the brewery in 13 days which I thought was impressive for a beer of that quality.

 

[tlo]

For those who've been experimenting with a combo of the 3 strains, how have you been calculating your pitching rates? Maybe more to the point, how many viable cells per gram are you assuming for each of the 3 strains? I ask, because the number of viable cell per gram seems to vary.

Fermentis data sheets say: greater than 6 B cells/g
Is that 6.1, 7, 10?

I found this Brewers Friend article and the supporting paper, which state:

S-04: 8 B cells/g
T-58: 18 B cells/g

MrMalty's pitching rates assumes 20 B cells/g and this home experiment on US-05 found similar numbers.

Forgive me if the answer is obvious. Since I started paying attention to pitching rates, I've only brewed with liquid yeast... so this is first time I've dug into dried yeast.

 

[TheHairyHop]

Agree that statement is ambiguous. And I'm not sure of the original article where they did those experiments.

Some interesting & relevant observations on killer strains from one of the original brewery-focused articles from 1973 (!!!)

http://onlinelibrary.wiley.com/doi/10.1002/j.2050-0416.1973.tb03515.x/pdf

1--Killing activity happens fast (within 24h of co-incubation)
2--Killing is influenced by the % inoculated at the start of a co-incubation:

Testing 50/50 and 10/90 mixes of killer/brewery yeasts resulted in complete kill of the brewery yeast within 24h of incubation at 28*C. "Some growth" of the brewery yeast occurred with a mix of 2%/98% killer/brewery yeast; table from the article suggests a mix of ~70%/30% viable killer/brewery yeast at the end of incubation.

In a test fermentation (2L of hopped 1.038 OG malt wort), "marked killer effect resulted only when the inoculum of killer strain was greater than 5%"
​

Application to us:

Even more strongly supports working hypothesis that CBC-1 is used as a carbonating/conditioning strain. Given the relatively small amount of cells that need to be added, it's probably not nearly enough to kill off all the previous yeast cells that were already present in the fermented beer. Thus the ability to grow/detect S-04, T-58, & WB-06. The fact that growing the dregs in fresh media results in a shift towards CBC-1 predominant samples fits nicely with all this too.

I assume the percentages are based on initial pitch, therefore if I'd want to introduce 5% CBC at the carbonation stage, I'd need to back out how much yeast is most likely in my beer at that time

 

[Jwin]

I wonder if the CBC is used for the sole purpose of killing off the other yeast in attempt to decrease biotransformation
A small amount kills the large colony of other yeasts, leaving enough of itself for carbonation, but not enough to screw with the Hop oils too much.
Maybe pitched with the first dry hop and in the FV, then the second dry hop and priming occurs in a conditioning tank ~24 hours later.
Just a thought.

 

[RevKev]

I wonder if the CBC is used for the sole purpose of killing off the other yeast in attempt to decrease biotransformation
A small amount kills the large colony of other yeasts, leaving enough of itself for carbonation, but not enough to screw with the Hop oils too much.
Maybe pitched with the first dry hop and in the FV, then the second dry hop and priming occurs in a conditioning tank ~24 hours later.
Just a thought.

Sounds like a reasonable hypothesis that could definitely be a reason. Pitching CBC to kill of the T58 before it gets to progressive and Belgiumy or as a yeast management tool is also a good thought

 

[isomerization]

The main idea that keeps me from thinking CBC-1 is used for that purpose (or as a sabotage to others propagating dregs) is that yeast autolysis is supposed to create terrible off flavors right? It's out dated now, but that was the whole idea behind secondaries right, get the beer off the yeast cake to prevent autolysis. We know that's not happening so fast, but the idea remains that lysed yeast taste bad.