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
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.
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.
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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
^^^^ Yep.
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.
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.
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.
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.
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.
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?
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.
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.
I respect and utilize science all the time. But when my direct experience is at odds with that science, what am I supposed to do? Contrary to what was stated above, I find stir plates DO make a difference. My starters are ready to go much sooner since I started using one. I prefer the results I get when I let the starter ferment fully, crash it and decant before pitching. And when it comes to beers over 1.040 OG, every beer I’ve mad a starter for has turned out better than any beer I haven’t. It’s not like I reached these conclusions in a vacuum. I have tried many methods and these are what have worked the best for me. At this point, I don’t care about science (in these situations) or someone else’s opinions…I’ve tried that stuff and this is how I make the best beer I can make.
Yes, you are correct. Cold fermentation slows metabolism, which, in turn, lengthens the replication period.
The details of OP’s brewing environment certainly reflect upon his or her experience pitching without a starter. This is a case where the brewer is receiving a solid amount of extremely fresh yeast of a strain that is very reliable for producing relatively clean beer. Changing any of those factors could give significantly different results. I suspect if OP selected a less popular strain OP may find the yeast to be not quite as fresh. That is certainly the case at the local shops in my area. Similarly, a more sensitive yeast strain or a more expressive strain may not respond so amicably without a little help. So to the extent that OP’s experiences accurately reflect his or her contention that a starter is unnecessary I would question that contention’s value under any other conditions.
I have said this many times before in these forums and is just my opinion. These low gravity worts 1.060ish are very forgiving of mistakes. That is why any novice can produce reasonably good beer. The real test of skills is high gravity 1.100+ worts, with these you need impeccable technique to achieve great beer. That is where proper yeast management really counts. I have learned the hard way that yeast management for me is much more critical than wort production.
…also WLP 001 is a very easy to use yeast, not at all temperamental. Great beginners yeast and again very forgiving of mistakes.
I’m not averse to the idea of a starter, it’s just been my experience that my beer has come out the other end tasting fine. I’m planning to brew some time next week and I’ll be doing a starter. I will be doing another batch of an amber ale I have on tap right now. I’d like to compare the two side by side to see what difference, if any, I can detect.
I’m always willing to try new things. If it works,I’ll incorporate it. If there is little to no difference, I’ll leave it out. K.I.S.S, the simpler the better for me.
I think it could also take some amount of skill to brew a sub 1.060 and have it be quaffable. I’m not sure I believe all the science about starters but I like to at least know the yeast is viable a day or 2 before brew day…+1 for starters
[quote=“Hooper, post:37, topic:19284, username:Hooper”]
That’s the nice thing about science. It doesn’t matter whether one believes. Either it is or is not. Now, whether what homebrewers post about starters is considered science…
Even better just to go with US-05. Especially if you aren’t going to make a starter.
That is what it’s all about.