[Rattlesnake44]

And the difference in time to reach cell density for 5gl was only 2.1 hours... Interesting. How could this possibly affect the final product in terms of taste?
By the way, this is the type of conversation I hoped to start with my original post. Thank you S. cerevisiae

[TMX]

Fwiw, I never made starters for 5 gallon batches, and they were all I brewed for the first 5 years.  I only lost one to infection, and if there were off flavours, it was something other than the yeast, like water from a water softener, failing to clean and rinse the PBW out of the fermenter.....

Sometime I think the yeast boogeyman is over stated....

[majorvices]

Are you gonna let us know when you have a 72 hour lag? No? Didn't think so.

Actually I've never had a beer lag more than 15-20 hours. I would be happy to let everyone on here know if/when that happens. I'll be sure to send you a special private message just to keep you in the loop buddy. cheers.

great! cause it is only a matter of time. (save the pm. and the emojis)

And you can save that bitterness for your next IPA. .

Ha! That was a good one!

Reading my posts from last night I sounded a bit of a jerk, and I apologize.

That said, if you have extremely fresh vials and under 1.065 I agree you can usually get away without a starter. But on vials that are a little past their prime, and that can be only a month or two after their production date, you are playing roulette. Remember that vials bought at HBS may not have been handled as well as you have hoped.

I just made a starter with two vials of yeast that were close to expiration and they took 2 days in 4L stirred starter to start to show signs of activity. Sure am glad I made a starter first!

I am lucky enough to have literally gallons of fresh yeast at my disposal whenever I need it so on smaller batches with different yeasts I don't have on hand at brewery I have gotten lazy and have taken to not makings starters as religiously as I once did. But I usually start with a low gravity beer (1.050ish) and pitch two vials in 5-6 gallons just to be safe. Then use that yeast for the rest of my series of whatever beers come after.

Also, I remember when WL had half of the viable cells in them than they do now. It was 1998-99(?) when they launched with "pitchable" vials. Glad they have been quietly upping the cell count over the years. 'Cause what they started with as "pitchable" certainly wasn't (and arguably isn't now).

[leejoreilly]

In my experience, Wort WANTS to become beer, and there are few absolutes in brewing. You can make fine beer with minimal concern for sanitation, recipe design, mash times, water chemistry, yeast health, fermentation temperatures, carbonation procedures etc. But each point of increased care and attention adds a few percentage points to your chances of making GREAT beer, and reduces by a few points your chances of disappointment. Sure, you can bag the yeast starter, never use O2 or a stir plate, "sanitize" with tap water, and so on, and still do OK; maybe for a few batches, maybe for a bunch. But I think the odds favor those who take the extra effort along the way.

[pete b]

You could also make several batches that came out great without sanitizing your equipment and come to the conclusion that sanitation doesn't matter. Its using best practices batch after batch that makes a good brewer. You can make a great beer with no starter and bad sanitation, but not every time.

[duboman]

You could also make several batches that came out great without sanitizing your equipment and come to the conclusion that sanitation doesn't matter. Its using best practices batch after batch that makes a good brewer. You can make a great beer with no starter and bad sanitation, but not every time.

Exactly and that was my original point, best practice means consistency and knowing my hard work will pay off as expected each and every batch

[Rattlesnake44]

I take my cleanliness and sanitation pretty seriously. That's never been a problem for me. I started brewing around '99-2000, always used dry yeast because it's what I could get by mail (no local HBS where I lived then). I've just started using White Lab vials fairly recently, last 3 years ish. It's what's available now at my LHBS and they get fresh in every Thursday. I usually pick one up a day or two before I brew, bring it home in a little cooler (usually with a growler or two, my local HBS is in the middle of about 5-6 local breweries). Put it in the fridge and take it out when I start my brew day.
I'm still not certain if I could tell the difference, in taste, between two batches where a starter was used in one and not the other. I have two taps on my kegerator though, so I'm willing to make the hard sacrifice here gents and maybe try a little experiment. It's for science!
And Major vices... Thank you for your post this morning.

[macbrews]

What pitching a larger number of cells does when pitching high gravity wort is allow for cell loss due to osmotic  pressure.  Osmotic pressure is a phenomenon that causes water to be drawn to the side of a semi-permeable membrane that has the highest level of solute, which is the wort.  This loss of water causes the cells to lose something known as turgor pressure.  The loss of turgor pressure is known as plasmolysis.  Turgor pressure pushes the cell membrane against the cell wall. Loss of turgor pressure causes the cells to shrink, resulting in shock, if not outright death.
[/quote]

Interesting stuff - brings up a few questions:

1)  What kind of cell loss should one expect when pitching directly from a vial, or smack-pack of commercial yeast?
2)  Does the fact that you are making a starter in a wort that is lower, but approaches the OG of your beer help buffer that loss/shock?
3) The math presented, I assume, is for optimum conditions.  Can we expect numbers that good for our homebrew if we add nutrients and oxygenate to a reasonable level?

Thanks,

Mac

[HoosierBrew]

In my experience, Wort WANTS to become beer, and there are few absolutes in brewing. You can make fine beer with minimal concern for sanitation, recipe design, mash times, water chemistry, yeast health, fermentation temperatures, carbonation procedures etc. But each point of increased care and attention adds a few percentage points to your chances of making GREAT beer, and reduces by a few points your chances of disappointment. Sure, you can bag the yeast starter, never use O2 or a stir plate, "sanitize" with tap water, and so on, and still do OK; maybe for a few batches, maybe for a bunch. But I think the odds favor those who take the extra effort along the way.

^^^^  Yep.

[erockrph]

There are so many details beyond just pitch rate that affects fermentation. Oxygenation, fermentation temps and schedule, wort gravity, yeast health, yada yada, all come into play. If one of these factors is a little off, then paying close attention to the others will probably make up for it in the majority of cases.

Is it best practice to never make a starter? Probably not. But I'm sure the majority of the time you will still come out with beer that is just fine as long as you're not sloppy with your other practices.

[S. cerevisiae]

Sure, you can bag the yeast starter, never use O2 or a stir plate, "sanitize" with tap water, and so on, and still do OK; maybe for a few batches, maybe for a bunch. But I think the odds favor those who take the extra effort along the way.

Steven Deeds and I have already proven that stir plates add little to no value when preparing a starter.  Stir plates were designed to prevent clumping in suspension cell culturing.  They crept into home brewing via people involved in cancer research, which is an area of science that is a big time user of suspension cell culturing.  Add in the fact that most home brewers propagate yeast incorrectly, and most stirred starters end up underperforming a simple shaken starter that is pitched at high krausen.


KISS (Keep It Simple, Stupid) is the best approach when propagating yeast.  Avoid introducing anything into the starter media that absolutely does not need to be there, including a stir bar.  Everything that comes into contact with the culture when it is small is an infection threat due to the fact that bacteria multiply eight-fold every time yeast cells double.  Boiling only kills vegetative cells, which is why I autoclave (pressure cook) the media that I use for my really small starters.

Dissolved O2 level matters, but one doesn't need to use pure O2.  The shaken, not stirred method (a.k.a. "James Bond Method") that I outlined in a couple of threads produces a very healthy starter.  It's a low-cost, low-tech, easy to perform method that produces excellent results. 

[S. cerevisiae]

Interesting stuff - brings up a few questions:

1)  What kind of cell loss should one expect when pitching directly from a vial, or smack-pack of commercial yeast?

Cell loss is strain, environment, and media composition composition dependent.  No yeast strain performs exactly the same way in two different environments.  Natural selection favors the cells that can handle the stress of the environment.  Environmental factors can cause beneficial mutations. That's why we have so many different yeast strains. 

2)  Does the fact that you are making a starter in a wort that is lower, but approaches the OG of your beer help buffer that loss/shock?

Starting low and stepping a starter up in gravity helps to buffer cell loss upon pitching into a batch of wort.  Starting low allows a culture that may have been in an extended period of quiescence undo the survival changes that it underwent in preparation for hard times without having to withstand high levels of osmotic pressure.  Stepping a culture up in gravity before pitching allows one to separate the wheat from the chaff cell-wise in a high cell count to wort ratio environment.   Natural selection kills off the weak cells removing them from competition with the strong cells. 

3) The math presented, I assume, is for optimum conditions.  Can we expect numbers that good for our homebrew if we add nutrients and oxygenate to a reasonable level?

Yes, the math is simplified for optimal conditions.  It does not factor in cell loss, which can be variable depending on the age and health of the mother cells.

[Philbrew]

Question for S. cerevisiae and others.

"What pitching a larger number of cells does when pitching high gravity wort is allow for cell loss due to osmotic  pressure."

When pitching to a lower gravity lager wort (say, 1.048 and 48*F) you also need big cell counts.  Is that because the low temp affects that 90 minute doubling time?

[S. cerevisiae]

And the difference in time to reach cell density for 5gl was only 2.1 hours... Interesting. How could this possibly affect the final product in terms of taste?

The main threat from pitching low with high gravity wort is underattenuation. The problem with high gravity wort is not only osmotic pressure, but also the fact that it is harder to dissolve O2 into high gravity wort. 

[narcout]

And the difference in time to reach cell density for 5gl was only 2.1 hours... Interesting. How could this possibly affect the final product in terms of taste?

The amount of cell growth, the rapidity with which it takes place, and the temperature at which it occurs all affect the overall flavor profile of the beer.  There's more to fermentation than just lag time and reaching your target gravity.

It's up to you as the brewer to determine what pitch rate, oxygenation level, fermentation temperature, etc. to use to get to your desired result.