[fredthecat]

I have made two batches recently with S-23. Both turned out great. The first was a light lager with 10% honey in the grain bill. The honey came through so well I decided I don’t want honey in my light lagers! It was a distraction.

My second S-23 batch was a SABL style beer. It is quite malty with 7% C60 and. 10% Munich I. Very good beer.
[/quote]

whats a SABL?

[denny]

SABL= Samuel Adams Boston Lager

[Bel Air Brewing]

The current ferment underway, with the 12th gen Diamond, is progressing better than the previous brews. Perhaps this is because the yeast slurry was fed with sterile wort, giving it a head start?

This is the one that literally was blowing stuff out of my storage jug. Under pressure. It was scary.

Previously, we just pitched the yeast directly from the fridge, without making any type of starter for it. It has always worked, but this time just seems to be doing a bit better based on the CO2 activity. Oh wait...might need to find a way to recapture that, do not want to harm the planet.

[Saccharomyces]

The current ferment underway, with the 12th gen Diamond, is progressing better than the previous brews. Perhaps this is because the yeast slurry was fed with sterile wort, giving it a head start?

You need be careful with the word “sterile.” I can assure you that wort is not absolutely sterile after boiling because the temperature is not high enough to kill spores. Wort has to be processed at 121C/250F under 15psi above normal atmospheric at sea level for 15 minutes  to render it sterile.

[Bel Air Brewing]

The current ferment underway, with the 12th gen Diamond, is progressing better than the previous brews. Perhaps this is because the yeast slurry was fed with sterile wort, giving it a head start?

You need be careful with the word “sterile.” I can assure you that wort is not absolutely sterile after boiling because the temperature is not high enough to kill spores. Wort has to be processed at 121C/250F under 15psi above normal atmospheric at sea level for 15 minutes  to render it sterile.

Ok, that's fine. So nothing we have done for over 3 decades can be considered sterile. No big deal, I guess.
Did not know that you had to hit 250 degrees.

[Saccharomyces]

Ok, that's fine. So nothing we have done for over 3 decades can be considered sterile. No big deal, I guess.
Did not know that you had to hit 250 degrees.

For lack of a better description, wort is pasteurized at the end of the boil, meaning that all vegetative cells have been killed. The wort is sterile enough for making beer, but not sterile enough for propagating pure cultures.

[Bel Air Brewing]

Ok, that's fine. So nothing we have done for over 3 decades can be considered sterile. No big deal, I guess.
Did not know that you had to hit 250 degrees.

For lack of a better description, wort is pasteurized at the end of the boil, meaning that all vegetative cells have been killed. The wort is sterile enough for making beer, but not sterile enough for propagating pure cultures.

So does this mean my 12th, 14th, or 20th harvested yeast slurry is no longer true to the 1st generation?

[fredthecat]

Ok, that's fine. So nothing we have done for over 3 decades can be considered sterile. No big deal, I guess.
Did not know that you had to hit 250 degrees.

For lack of a better description, wort is pasteurized at the end of the boil, meaning that all vegetative cells have been killed. The wort is sterile enough for making beer, but not sterile enough for propagating pure cultures.

So does this mean my 12th, 14th, or 20th harvested yeast slurry is no longer true to the 1st generation?

what does that even mean? do you think the beer that you made after several "generations" of yeast growth tastes the same or similar to the first one?

 if it doesn't, then buy a new sachet of yeast. if it does, and you find the taste pleasing then brew on.

[Bel Air Brewing]

Let me help…

Yeast mutates. We are on generation XXX. Not sure which variant we are actually on. And now we know we can’t propagate pure cultures as our wort is not sterile. But the yeast does spread, but seems less effective with each new variant. 

We brew different beer styles with each generation, so no way to do an A / B comparison.

All the beer is good, very good. So there is your answer.

The 3 latest kegs are wicked good, a German Pils, Vienna Lager, and Festbier. All made with the same yeast. I have 6 new dry packages of Diamond, but no need to use them yet.

[fredthecat]

Let me help…

Yeast mutates. We are on generation XXX. Not sure which variant we are actually on. And now we know we can’t propagate pure cultures as our wort is not sterile. But the yeast does spread, but seems less effective with each new variant. 

We brew different beer styles with each generation, so no way to do an A / B comparison.

All the beer is good, very good. So there is your answer.

The 3 latest kegs are wicked good, a German Pils, Vienna Lager, and Festbier. All made with the same yeast. I have 6 new dry packages of Diamond, but no need to use them yet.

You are on generation "xxx", you mean 30? what is a "variant" of yeast and why do you believe you have a "variant" rather than diamond lager yeast?

what do you mean the yeast "spreads"?

you absolutely could compare german pils, vienna lager and festbier they are incredibly similar beers. if you noticed some very different esters or yeast related profile elements you could assume its the yeast.

i really don't know what youre on about as you've basically stated that you're happy with the yeast's results. im not even sure if diamond is confirmed as either cerevisiae or pastorianus, but it is not radically mutating every single batch as you (plural) seem to imagine it is. you have diamond lager yeast.

[Iliff Ave]

If your results are good who cares? Suprised you can go that long without some serious mutation.

[Bel Air Brewing]

If your results are good who cares? Suprised you can go that long without some serious mutation.

We keep the harvest hyper clean. And the aroma is what I go by. If it still has a clean fresh fragrance, we go with it.
Not sure how many times this particular yeast has been harvested, but way more than a dozen.
That’s why I said gen XXX. I really lost count.

Yes, the results are still very good.

[Saccharomyces]

So does this mean my 12th, 14th, or 20th harvested yeast slurry is no longer true to the 1st generation?

In addition to wort not being absolutely sterile, most pitching cultures pick up house microflora over time.  No matter what steps one takes brewing yeast will be subjected to house dust at one point or another during normal brewing operations. House microflora does not crawl into one's fermentation vessel.  It rides through the air on house dust.  The pitched culture will be the dominate culture, but it will not be the only culture after repitching many times.  Eventually variants will enter the picture as well and how one crops and repitches will place selective pressure on the variants that form.  Variants are cells from the original reference culture with mutations. Not all of the cells will be variants and not all variants produce bad beer. Yeast cells are a model organism for studying genetics for a reason.

With that said, I do not think that serially repitching a culture is a bad thing.  The more time a culture is repitched, the more robust it gets because repitching places selective pressure on the culture.  What matters is if one is happy with how the culture has drifted.  The cultures we enjoy today are all the result of genetic drift from being repitched.  The practice of going back and creating a new seed culture every few batches is relatively new in the grand scheme of brewing.  The head brewer at Anchor commented a few years ago that they just serially repitch the culture without boing back and growing a new seed culture every few batches. I am sure that is why their Christian Schmidt-based culture is so stable.  It has been repitched and pushed into a certain direction since the seventies.  The culture may not be as stable in another brewery, but it has adapted to Anchor's brew house.  How we take our crop and how much we repitch are critical to the longevity of a culture.  Your practice is not ideal for long-term health of a culture.  Biomass growth is necessary to sustain a culture over time.  When repitching, only the sedimented volume counts. I am pretty sure that when you say that you pitched two quarts of cropped yeast, you are pitching supernatant along with yeast solids, so your pitch rate is a little misleading.  Most brewers, when they talk about repitching slurrly, they are talking about thick sedimented slurry.  You should only count the sedminented volume as your pitch.  Most of us discard the supernatant when repitching.

[Bel Air Brewing]

Ok...you got me going in a whole other direction now. We are getting ready to keg 10 gallons of Tex-Festbier, brewed with Texas Premium Pilsner Malt (look for a full review to come). The yeast will be harvested, as always, but this time the yeast volume will be divided in two.

My yeast slurry is stored in gallon glass jugs. It is allowed to sediment out, with about two inches of crystal clear beer forming on top of the yeast cake after a few days. This beer is then decanted, and the remaining yeast is normally pitched in this manner. Only last time did I feed boiled and cooled wort into the yeast, gave the jug a good shake, at which time it awoke with violent explosions.

Our sediment is peanut butter like in viscosity. It requires a huge effort to get it suspended in solution prior to pitching.

I estimate that 2/3's of the slurry is pretty much solid (peanut butter like) yeast cake. It is free of undesirable items. Any particulate matter that is there is microscopic in size, as to the naked eye it appears hyper-clean.

Because the harvesting is done in my brewery / shop, in the open air, certainly wild yeast and/or dust has been introduced.

Suggestions on how we can improve our operation are welcome.

I will get some good up close photos of our yeast, and post them here. I'm certain that most of the brewers on this forum are more advanced in this than we are.

All of the beers brewed with the multi-generational yeast have been very good. So as of today, that is not something that we are concerned about.

These pictures do not represent Diamond we harvested. Instead, Wyeast London Ale on the left, S-04 on the right.

[denny]

Ok, that's fine. So nothing we have done for over 3 decades can be considered sterile. No big deal, I guess.
Did not know that you had to hit 250 degrees.

For lack of a better description, wort is pasteurized at the end of the boil, meaning that all vegetative cells have been killed. The wort is sterile enough for making beer, but not sterile enough for propagating pure cultures.

So does this mean my 12th, 14th, or 20th harvested yeast slurry is no longer true to the 1st generation?

Very likely