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Yeast pitch rate: Single vial vs. Yeast starter | exbeeriment results!

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Spelling error: "...beer fermented with a “proper” amoutnt of cells propagated..."

Pictures are fun but when illustrations really count (i.e. statistical analysis) you're blank. I like to look at charts and graphs, they go a long way with illustrating statistical results IMO.

Good experiment and not at all surprising. I brewed for years with single smack pack pitches and made good beer, although lag times were always longer than with larger pitches.
 
For experiments like this, it would probably be a good idea to go with a recipe that doesn't allow any off-flavors to hide. But the experiment shows that at least one can make an amber ale with or without a starter.
 
This is my favorite one so far. I love it. I haven't used a yeast calculator for over 6 months and I'm glad. I've felt they are unnecessary. Low and behold it's proven.

Proven is WAAAAY too strong. the correct conclusion from my article is that we

"Failed to prove making a starter with WLP090 resulted in a statistically significant difference, when compared to a direct-pitched vial on this particular wort"
 
Proven is WAAAAY too strong. the correct conclusion from my article is that we

"Failed to prove making a starter with WLP090 resulted in a statistically significant difference, when compared to a direct-pitched vial on this particular wort"

I gotcha ;)

It did prove to me though that high pitch rates are virtually meaningless. I realize this is only one particular strain and one particular beer. Time after time (I drink a lot of beer) I make fantastic beer by 'under pitching' and will continue to do so.
 
Spelling error: "...beer fermented with a “proper” amoutnt of cells propagated..."

Pictures are fun but when illustrations really count (i.e. statistical analysis) you're blank. I like to look at charts and graphs, they go a long way with illustrating statistical results IMO.

Good experiment and not at all surprising. I brewed for years with single smack pack pitches and made good beer, although lag times were always longer than with larger pitches.

Thanks. Fixed.

I can't think of anything, chart wise, that would have made this more clear. 9/20 got it right. 8/20 chose one of the two wrong beers, while only 3 chose the other wrong answer.


As for all the discussion about how broadly this could generalize, the prudent behavior is to simply not generalize from a single data point. When we repeat on a different beer/strain/etc... we can then re-evaluate the results and see if there can be any inferences made between the two points. ie: if we did it again with a similar recipe, but a higher gravity and used the same yeast, and a significant difference... we might be able to infer that that higher gravity wort responds more to pitch rates (which would confirm the conventional wisdom).

With a single data point, we can't really infer anything beyond the very narrow scope.

As for the "You should try it on a different kind of beer to really see what is going on"...

Umm... maybe? I think it is important to understand that at the end of the day, I am still brewing the beers I want to drink, my family wants, etc... So while yes, some are going to be more subtle beers, I am not really choosing the beer to try and find a particular xBmt result. I am more choosing the beer I want to brew next, then picking a xBmt from our queue that is, frankly, easily applied... methodologically speaking, to the brew process of that beer. (for example... I may do Sucrose vs. Dextrose... and while a belgian tripel might be a great yeast test beer, it is also a good sugar test beer, in a way that I can't really do a sucrose vs. Dextrose on another style... etc...)
 
I was thinking the use of a "Super Yeast" like WLP090 might have an effect on the experiment. A lower attenuating yeast that has a lot of character would have been more interesting.

I was thinking the same thing. Either way, an interesting article. I will still use starters (as will the author).
 
Let's say we do this same experiment again and again...would we get the same results? Yes. It was a very controlled experiment. It's not like flipping a coin and I find it hard to believe that you would even use that to compare.

First, we may or may not get the same results; we don't know. This is precisely what we are trying to estimate. We are modeling a random process with a single binary outcome (in this case "are the beers different or not ") where the only influencing factor is the pitch rate, which we can effectively model as binary as well ("low" or "high"). I make the comparison to a coin being flipped to illustrate the fact that, no matter what the higher-level process is, if we are modeling some stochastic process with binary outcomes, the uncertainty in the final estimate is rather high with only one observation. While it is a minor simplification to the true model, I think the coin flipping example illustrates the point that any estimate derived from a small sample size lacks information in the statistical sense.

As a short description, and using the coin example for now, assume we have a coin with unknown bias, which we call p. In a fair coin, the value of p is one half, or .5. We are trying to estimate the posterior over the variable p given data, X, where X is a set that contains one or more observed results. If we use the traditional conjugate prior (the Beta distribution) for the Bernoulli distribution parameterized by p, we can easily (in closed form) compute a posterior estimate for p dependent on the observations we've seen. Further, the volume of uncertainty in the value of p will reduce more and more with more observations in the set X. This can be seen from the formula for the entropy of the Beta distribution. This means that if the set X is small (we only have on observation of an outcome, or 1 experiment in this case) then the uncertainty in the estimate of p is actually pretty high. I used the limiting case in my first post, where I said if you saw only a single flip of the coin (or 1 experimental result) would you trust the frequentist analysis that says "the coin is biased completely" or p = 1. No, of course you wouldn't. Unfortunately, with little or no a priori information about p (low values for the hyperparameters of the Beta distribution), only more data helps in estimating p; what I was saying is that I cannot with any confidence estimate whether or not pitch rate does or doesn't matter from a single experimental outcome.

My hypothesis is that pitch rate is not the only thing that matters; I think gravity, yeast, fermentation temperature, etc. all matter. That's why I said that selecting basically any lager over 1.050 that is pitched and fermented around 50 F will most likely show the opposite. Maibock is another great example. And I think that this particular beer is not as informative because it's an ale with a lot of hops and a fairly clean yeast. I think if you changed that, and made it a high gravity beer requiring a fairly clean profile, and fermented at low temps, you'll likely see a very different result. What I think that this experiment "proves" is that one CAN make a good hoppy, amber beer with OG of ~1.065 with WLP090 when pitching a starter or not, which I think someone else has already noted.

Also, I am definitely not trying to be a jerk. I just proofread this and thought it may come off that way, and if it does, I apologize. I'm just trying to explain what I meant, and why I made the comparison.
 
My hypothesis is that pitch rate is not the only thing that matters; I think gravity, yeast, fermentation temperature, etc. all matter. That's why I said that selecting basically any lager over 1.050 that is pitched and fermented around 50 F will most likely show the opposite. Maibock is another great example. And I think that this particular beer is not as informative because it's an ale with a lot of hops and a fairly clean yeast. I think if you changed that, and made it a high gravity beer requiring a fairly clean profile, and fermented at low temps, you'll likely see a very different result. What I think that this experiment "proves" is that one CAN make a good hoppy, amber beer with OG of ~1.065 with WLP090 when pitching a starter or not, which I think someone else has already noted.

Also, I am definitely not trying to be a jerk. I just proofread this and thought it may come off that way, and if it does, I apologize. I'm just trying to explain what I meant, and why I made the comparison.

I don't think that you came off like a jerk.

What I have to back my view up is only conjecture and my perception of all the beer I brew. It's all good and I'm sure it's all 'under pitched.'

What I gather from your replies is that this experiment is just one of many that we would have to do in order for the 'correct' outcome. I see and I don't totally disagree...however:

I do believe that the results of this wouldn't matter for beer or yeast with an SG of <1.065. As I stated that is just conjecture but I base it on all the beer I brew.
 
what I was saying is that I cannot with any confidence estimate whether or not pitch rate does or doesn't matter from a single experimental outcome.
...
What I think that this experiment "proves" is that one CAN make a good hoppy, amber beer with OG of ~1.065 with WLP090 when pitching a starter or not, which I think someone else has already noted.


I am in agreement with your read of things here. I should point out what the test DID NOT prove. It did not PROVE that the beers were even indistinguishable.

My subjective experience was that they were very nearly identical, if not identical.

But the statistics did not show a "identical" result, the statistics say that they were unable to be reliably distinguished, which is different from being identical.
 
Again, not a counter-argument to what I'm saying. What I'm saying is I'd trust your tasting results more than hers because she is not certified; the reason for that is that I have no other basis to go on. You (and maybe a select few other individuals) are the only person/people that know(s) that she is a great taster. So yes, you may trust her in a triangle test, but how am I supposed to trust her? This is exactly what certification provides (in any field, not just tasting): a way to provide some information to the consumer of their services as to whether or not (and at what level) that person has experience with the task they are performing.

Thus, I am not saying she is better or worse than you or anyone else; I'm saying that since the person reading the experimental results has no idea what qualifications the evaluators of the beer have, then there is a great deal of uncertainty in the result, and that little, and perhaps no, conclusion can be drawn with respect the higher-level question of "how much does pitch rate matter?". For that, I would rather trust the vast amount of literature and lab experimental results that indeed show that pitch rate matters.

I believe that you and I have conversed on this topic before (the validity of experimental results and their impact at the homebrew level), and this is yet another case where I like the experiment, but the data provided is minimal, and effectively proves nothing, because it is a single data point with very subjective metrics (the subjectivity of which, I am arguing, could be mitigated with certification/credentials).


I didn't intend it as a counterpoint, I was agreeing with you. And you probably have discussed this with me before as I have a hate-on for attempts to over science homebrewing. At a 5gal scale, its as much of an art as a science.

And a point I posted earlier that I think got lost in the noise:
When I started homebrewing 5 years ago and the wyeast smack packs were half the size they are now. The mr malty calculator was one of the things that had a huge positive influence on the quality of my beer but now the smack packs have grown but the calculator hasn't changed. ...and not all yeast is the same. If this experiment is going to be redone with English or Belgian yeast, go with the super flocculating, diacetyl bomb producing wy1968 London ESB. There is no way you are making a decent 5%+ ABV, 5gal batch without a starter with that one.
 
Interesting test... My first instinct, on looking at the setup of the test and recipe choice, is that using a beer that has any kind of significant hop presence could mask some flaws or off-flavors. That said...

A buddy of mine and I did a similar test a few years back, with a traditional German bock. I pitched a Mr Malty-recommended starter, he pitched a single smack pack. And the result? Like this experiment saw, the beer with starter took off in a matter of a few hours, while the single smack pack beer required 3 days to show any signs of life - and 2 of those were outside the ferment chamber, so were closer to ale temps to ramp up. Also like this experiment, you could detect very subtle flavor differences between the two (we never tried a triangle test - we weren't quite that sophisticated). But of all the folks that tried them both - our homebrew club included - nobody could really determine a strong preference for one over the other, or detect anything like a flaw. I'd have to look up in my notes what yeast strain we used...

We actually just repeated this test - or are in the process of doing so - with a Munich Dunkel using Wyeast Bavarian Lager Yeast. My starter was a little smaller this time around (using K. Troester's growth estimates these days), and so far the only difference we've seen is mine had about 12 hours less lag time. We'll know more in a couple months how the finished products compare - but I actually suspect that the results will be similar to our last lager experiment. I may talk to him about presenting a triangle test to our club to see if that determines anything interesting.
 
There is no way you are making a decent 5%+ ABV, 5gal batch without a starter with that one.

No offense to the poster, but how specifically do you know that this statement is true? You say 'no way', meaning that you think it is impossible. Have you done an exhaustive search of this assertion? If not, then you probably shouldn't make such a statement.

This is what I like about the Brulosophy experiments, they question these absolute assertions that people like to make that they haven't actually tested.
 
No offense to the poster, but how specifically do you know that this statement is true? You say 'no way', meaning that you think it is impossible. Have you done an exhaustive search of this assertion? If not, then you probably shouldn't make such a statement.

This is what I like about the Brulosophy experiments, they question these absolute assertions that people like to make that they haven't actually tested.

I've done 20+ batches with 1968. It needs a big pitch or it has a weak krausen and flocs out early leaving a ton of diacetyl. so that's at least 19 more data points than the experiment has. I'm lazy and would much rather just pitch a pack directly but it just doesn't work well. There are countless threads on hbt like this https://www.homebrewtalk.com/showthread.php?t=267303 see the wyeast response I posted on the last page. Lately I've been brewubg a half batch of <1.040 OG beer and pitch a single smack pack directly to use as a drinkable starter for the next batch. Anything bigger or stronger and it craps out. Maybe this can be overcome with a ridiculous amount of pure O2 but I haven't tried that
 
I've done 20+ batches with 1968. It needs a big pitch or it has a weak krausen and flocs out early leaving a ton of diacetyl. so that's at least 19 more data points than the experiment has. I'm lazy and would much rather just pitch a pack directly but it just doesn't work well. There are countless threads on hbt like this https://www.homebrewtalk.com/showthread.php?t=267303 see the wyeast response I posted on the last page. Lately I've been brewubg a half batch of <1.040 OG beer and pitch a single smack pack directly to use as a drinkable starter for the next batch. Anything bigger or stronger and it craps out. Maybe this can be overcome with a ridiculous amount of pure O2 but I haven't tried that

My experience is right on with yours. I think it may have to do with high flocc yeasts and temp control. I've used a number of them recently and it seems like once they get going they don't like to be cooled back down. Some of the yeast just drops out. I'm going to try a lightweight cover like a t-shirt to try an prevent the outside of the fermentor cooling down too much. When I caught 1968 at the right temp while fermentation was finishing up, I got 77% aa.
 
The only rebuttal I have to the write-ups is to the following statement:

the slower completion time means a slower overall turnaround for a batch, if only by a couple days &#8211; this makes a difference if I am trying to get a beer ready for an event of some kind.

Isn't that all negated by taking a couple of days to make the starter?
 
The only rebuttal I have to the write-ups is to the following statement:



Isn't that all negated by taking a couple of days to make the starter?

Not really. I mean... I usually don't have time to brew through the week, but it only takes 10-15 minutes to make a starter if I think I will be brewing next weekend.
 
Not really. I mean... I usually don't have time to brew through the week, but it only takes 10-15 minutes to make a starter if I think I will be brewing next weekend.


If you have time management skills, it's pretty easy to plan things out and save money making yeast starters. Starter takes the amount of time it takes to sanitize a growler, and boil a few cups of water. I mean, that's 30 minutes tops.
 
Not really. I mean... I usually don't have time to brew through the week, but it only takes 10-15 minutes to make a starter if I think I will be brewing next weekend.

That is not what I thought you meant when I read the article. Thanks for clarifying.
 
I think I get the point of this experiment.

Based on my own experience, it strikes a chord with me. I've done several high gravity ales using far less than the recommended yeast amounts when I pitched yeast.

Those ales turned out fine. Amazing good in many instances. In the last couple of years I've made an effort to pitch much larger amounts of yeast into these ales. The results haven't been dramatically different or better. In many cases, they haven't been as good. It has made me wonder about whether or not stressing yeast is as big a deal as folks make it out to be.

Lately I'm beginning to believe that under-pitching isn't as big a deal as it was once thought to be. In fact, I'm thinking that it may not even be much of a big deal at all. What I'm finding to be more important is fermentation temperature and sanitation. Simple basics really.

Larger pitch rates provides quicker turn-arounds, and that is about all. Yeah, there may be a minor difference in taste occasionally. But for me, it isn't anything that is enough to break any batch of beer. In the end, the beer is still good. The difference is so slight, if any at all, that I can't notice it.

Maybe I'm a barbarian that can't taste the difference between a great ale and a fine ale. That could be true. But do I consider it a curse? No. I actually think it's a blessing. Then again, I don't believe my palate is inferior. I think my tastes aren't dependent on folklore. I taste what I taste and I only like what I like. I like my beer.

I've found that I'm as happy with my under-pitched beer as I am with my over-pitched beer. More often than not, the under-pitched stuff is just as good as the other.
 
Thanks for doing all that Ray, was a great read.

You put the chamber temperature probe on the Starter carboy... with the different ferment rates and times do you think there might have been a significant difference in ferment temperatures?
 
Isn't that all negated by taking a couple of days to make the starter?

No, because the starter is made before brewday, so it doesn't affect batch turnaround.

Why do you think you have to buy only one vial?

Pitching multiple vials might decrease lag time, but the advantage of a starter is more than just the pitch rate: a well-timed starter can be pitched into the wort when the yeast are active, meaning you pitch them into the wort and they get right to work. Yeast straight from the vial or a dry packet aren't active when they hit the wort so it takes time for them to get to work. For that reason, a Wyeast smack pack, properly smacked in advance of pitching, should have less lag time because smacking the pack gets the yeast moving as if you had made a miniature starter.
 
Not really. I mean... I usually don't have time to brew through the week, but it only takes 10-15 minutes to make a starter if I think I will be brewing next weekend.


If you have time management skills, it's pretty easy to plan things out and save money making yeast starters. Starter takes the amount of time it takes to sanitize a growler, and boil a few cups of water. I mean, that's 30 minutes tops.
Just plan it out and you can be just as efficient as you would be using any other yeast method
 
I think I get the point of this experiment.

Based on my own experience, it strikes a chord with me. I've done several high gravity ales using far less than the recommended yeast amounts when I pitched yeast.

Those ales turned out fine. Amazing good in many instances. In the last couple of years I've made an effort to pitch much larger amounts of yeast into these ales. The results haven't been dramatically different or better. In many cases, they haven't been as good. It has made me wonder about whether or not stressing yeast is as big a deal as folks make it out to be.

Lately I'm beginning to believe that under-pitching isn't as big a deal as it was once thought to be. In fact, I'm thinking that it may not even be much of a big deal at all. What I'm finding to be more important is fermentation temperature and sanitation. Simple basics really.

Larger pitch rates provides quicker turn-arounds, and that is about all. Yeah, there may be a minor difference in taste occasionally. But for me, it isn't anything that is enough to break any batch of beer. In the end, the beer is still good. The difference is so slight, if any at all, that I can't notice it.

Maybe I'm a barbarian that can't taste the difference between a great ale and a fine ale. That could be true. But do I consider it a curse? No. I actually think it's a blessing. Then again, I don't believe my palate is inferior. I think my tastes aren't dependent on folklore. I taste what I taste and I only like what I like. I like my beer.

I've found that I'm as happy with my under-pitched beer as I am with my over-pitched beer. More often than not, the under-pitched stuff is just as good as the other.

You need to be really careful of thinking like this. Questioning the old ways will lead you down paths that few dare to tread. Next thing you'll find yourself doing is researching pitch rates and then you'll probably find the article where Gordon Strong stated that he often pitches a single smack pack or vial into his lager. Now why would an award winning brewer screw up a batch of lager by pitching such a small amount of yeast? Wouldn't he notice the off flavors produced by the under pitch....or doesn't it produce the off flavors if you treat it right?

Once you begin down the path of questioning these old ways you may decide to explore shorter mash times too.:D
 

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