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

[hottpeper13]

All I can say is when I first started ~4yrs ago, my beers took 8-12 weeks of conditioning in the bottle before they were very good beers, before then they were ok but I thought, I won't be brewing that one again. After perusing this site it seemed I was underpitching. So I built a lego stirplate and soon(using Yeast Calk) my beers were awesome in as little as 4 weeks, as soon as carbonation is done. Besides I store a small portion of each starter for making another so I only have to buy 1 pkg. At this time I have 7 strains.

 

[mkeckjr]

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.

Sorry about that, gbx. I totally misinterpreted your previous post. Cheers.

 

[Weezy]

The experiment in question is a single snapshot with low statistical power and relies pretty mostly on sensory evaluation. Do all yeasts behave this way? Does WLP090 behave like this in other worts? Even in the same wort, what percentage of the time does an underpitched batch still complete fermentation without undesirable off-flavors?

While interesting, I would be very cautious to generalize from this. Will an underpitched beer necessarily give you problems or taste bad? Certainly not. Does underpitching increase the odds for these things? It certainly does.

Very true but I must point out that the status quo, i.e. Mr. Malty website, is just as empirically derived and he's never offered up his raw data for others to review...and we do know that his data is based on one yeast only.

 

[gbx]

Very true but I must point out that the status quo, i.e. Mr. Malty website, is just as empirically derived and he's never offered up his raw data for others to review...and we do know that his data is based on one yeast only.

I think Mr Malty is a good guide but it isn't anything close to science. The numbers that Mr Malty outputs are twice as big as what the yeast manufacturers say is optimal. It assumes that all ale strains require an equal pitch (they certainly do not). It was written years ago and hasn't been changed to reflect the new packaging of both wyeast and white labs. (wyeast packs used to be 25 billion cells but now they are 100 billion) Even the dry yeast has changed since then (nottingham didn't use to be vaccuum sealed). I still use it when repitching slurry but consider it the upper range of what is needed.

 

[stratslinger]

I think Mr Malty is a good guide but it isn't anything close to science. The numbers that Mr Malty outputs are twice as big as what the yeast manufacturers say is optimal. It assumes that all ale strains require an equal pitch (they certainly do not). It was written years ago and hasn't been changed to reflect the new packaging of both wyeast and white labs. (wyeast packs used to be 25 billion cells but now they are 100 billion) Even the dry yeast has changed since then (nottingham didn't use to be vaccuum sealed). I still use it when repitching slurry but consider it the upper range of what is needed.

Not judging here, but I'm curious as to your logic.

You're stating here that because Mr Malty was written back when yeast packs used to be 25 billion cells and now they're 100 billion, that it's recommended final pitching rates are suspect?

For one, Mr Malty defaults to 100 billion cells, which suggests that it's been at least updated in that timeframe.

For two, regardless of what cell count you drop into a Starter, MrMalty is suggesting how many cells that Starter should finish with. The only thing that bigger vials/smack packs would impact here is the size of the starter to get to the suggested pitch rate.

What am I missing?

 

[motobrewer]

I think Mr Malty is a good guide but it isn't anything close to science. The numbers that Mr Malty outputs are twice as big as what the yeast manufacturers say is optimal. It assumes that all ale strains require an equal pitch (they certainly do not). It was written years ago and hasn't been changed to reflect the new packaging of both wyeast and white labs. (wyeast packs used to be 25 billion cells but now they are 100 billion) Even the dry yeast has changed since then (nottingham didn't use to be vaccuum sealed). I still use it when repitching slurry but consider it the upper range of what is needed.

I don't think this is true at all. The pitch rates in MrMalty are consistent to what's in Yeast (published 2014), by Chris White (from, White Labs) and Jamil Zainasheff (from, MrMalty)

 

[stratslinger]

I don't think this is true at all. The pitch rates in MrMalty are consistent to what's in Yeast (published 2014), by Chris White (from, White Labs) and Jamil Zainasheff (from, MrMalty)

It was published originally in 2010 actually - still a good point. 2010 just isn't all that dated...

 

[motobrewer]

It was published originally in 2010 actually - still a good point. 2010 just isn't all that dated...

woah really?

oh yeah you're right - i was thinking the Water book.

 

[Weezy]

It'd could have been written and printed yesterday, the point is its completely empirical. Precisely measuring the yeast density doesn't change the fact that the all he's saying is that fermenting at that yeast density with chico results in well attenuated, good tasting beer. because its wrapped in a book makes it somehow more scientific than anymans home brew test that says brewing at X cell density with Y yeast results in a well attenuated, good tasting beer?

 

[motobrewer]

I was simply addressing gbx's comment that MrMalty's output is twice as high as the yeast manufacturers' recommendations, considering Chris White wrote a book that validates it.

 

[blizz81]

It'd could have been written and printed yesterday, the point is its completely empirical. Precisely measuring the yeast density doesn't change the fact that the all he's saying is that fermenting at that yeast density with chico results in well attenuated, good tasting beer. because its wrapped in a book makes it somehow more scientific than anymans home brew test that says brewing at X cell density with Y yeast results in a well attenuated, good tasting beer?

I dunno. If Chris White takes his life work with yeast and makes some conclusions and writes a book with certain conclusions and recommendations for optimal results, I'm probably going to give that a bit more credibility than someone posting their personal homebrewing results on here that could be the one youtube "how to brew beer redneck style" guy.


The Xbeeriments and the like are a fun in-between of those extremes.

 

[joshesmusica]

and what's also cool about the exbeeriments being the in-between, is that the people commenting on this thread are also all over that extremity. from the person who says, "hell yeah man! i'm never doing a starter again!" (and yes that was meant to be interpreted as being said by the Murica! guy) To the guy who says, "egh-hum, excuse me sirs, this is one single data point, from one particular strain, in one particular beer, in one experiment of that beer. therefore this experiment proves nothing." (and yes that was meant to be interpreted as being said in an incredibly nerdy, pocket-protector wearing, guy who pushes his glasses up his nose during the egh-hum part.) somewhere in there i assume there's an in-between.

i, for one, thoroughly enjoy these experiments and wish more people were doing something like this. i'm going to begin experimenting with things soon, and am honestly jealous of the size of their tasting panels (even if it is too small for some people's likings). the guys doing these experiments, and the ones interpreting it as one of those in-betweeners, realizes that it's not the end of the discussion. but it is a pretty damn good start to the discussion, considering up to this point there's been no discussion, only that we're all told we must make a starter with liquid yeast, we must control our temperatures down to the .1F, we must siphon out the trub before fermentation, we must do this and that and so on.
These guys, and the ones with the balanced viewpoint, are simply looking for more precision, better turnaround time, easier brew days, etc. in order for this HOBBY to be more fun and to produce the best beer that we can. If that means that in an average sized beer that is semi-hop forward we can straight up just pitch one vial of yeast as long as we're in no hurry for it to get on with it, then now we can start doing more testing of that. if that means for a paler, slightly more malt forward beer i can just toss everything into the fermenter, then i'm gonna start doing it and testing for myself.

but then again, i've always been the type to question the status quo, whether that's religion, politics, "historical" education, or how to home brew beer.

 

[Weezy]

I dunno. If Chris White takes his life work with yeast and makes some conclusions and writes a book with certain conclusions and recommendations for optimal results, I'm probably going to give that a bit more credibility than someone posting their personal homebrewing results on here that could be the one youtube "how to brew beer redneck style" guy.


The Xbeeriments and the like are a fun in-between of those extremes.

I'm not saying we shouldn't believe what Mr. white is saying. At the end of the day, there's no lab experiment to say that beer was brewed well or not; if you pitched an appropriate amount of yeast or not. the flavor and quality of a beer is a completely unscientific test. A masters in organic chemistry does not give you improved taste buds. Any amount of theory falls off the cliff when it can only be proven by someone's arbitrary taste buds.

What does Mr. White's purepitch yeast packets recommend for a pitching rate (1 pack for 5 gal under 1.070) What does the Yeast book/mrmalty.com say for 5 gal of 1.065??

i.e. pitching rates and appropriate yeast cell densities are a lot more liberal than what is regurgitated as gospel. The book and Mr. Malty are very conservative so that you can be sure you have enough yeast. That's all. They can't get more precise than that.
RDWHAHB.

 

[FatDragon]

Yeast spec sheets often list numbers that seem weird to homebrewers. For a single example, US-05 lists temperature ranges of 54F-77F, where most of us prefer not to use it anywhere outside of the 62-68 range, and just about any yeast spec sheet is going to be the same way. You can ferment anywhere in that range (and possibly even outside of it), but that doesn't mean your beer will be as good. I suspect recommended pitch rates are the same way - if the instructions read 1 vial per 5 gallons of 1.070 wort, it'll ferment your beer at that rate, but it might come out more like the 77 degree beer than the 64 degree beer. I've read one homebrew experiment where they pitched 1% (I think) of the recommended rate in a beer and it attenuated fully and produced a decent (but not great) beer. Yeast will ferment in a lot of conditions, but there's a lot of anecdote out there about what conditions led to the best beer. That's not to say don't challenge the status quo - much of today's status quo was heresy ten years ago - but the current line of reasoning on yeast pitch rates is based on a lot of experience and at least marginally-scientific experimentation, so there's certainly something to them, even if they're not the final answer.

 

[joshesmusica]

Yeast spec sheets often list numbers that seem weird to homebrewers. For a single example, US-05 lists temperature ranges of 54F-77F, where most of us prefer not to use it anywhere outside of the 62-68 range, and just about any yeast spec sheet is going to be the same way. You can ferment anywhere in that range (and possibly even outside of it), but that doesn't mean your beer will be as good. I suspect recommended pitch rates are the same way - if the instructions read 1 vial per 5 gallons of 1.070 wort, it'll ferment your beer at that rate, but it might come out more like the 77 degree beer than the 64 degree beer. I've read one homebrew experiment where they pitched 1% (I think) of the recommended rate in a beer and it attenuated fully and produced a decent (but not great) beer. Yeast will ferment in a lot of conditions, but there's a lot of anecdote out there about what conditions led to the best beer. That's not to say don't challenge the status quo - much of today's status quo was heresy ten years ago - but the current line of reasoning on yeast pitch rates is based on a lot of experience and at least marginally-scientific experimentation, so there's certainly something to them, even if they're not the final answer.

i completely agree. who knows if we'll ever find the final answer? Maybe we'll come up with a good set of data sheets that say for this style of beer at this gravity you should do this with the trub, this with the hops, this with the yeast, this with the temps, etc. But then a future generation will come along and question all of that.

I also want to point out, I won't stop "overpitching" simply because of the fact that this experiment showed what all of us know pretty well, "proper" pitch rates into properly aerated wort will take away a significant chunk of that lag time. I want to get that turnaround time as short as I can get it.

 

[stratslinger]

Another thing that might be interesting to test - but would certainly take a considerably longer period, is another of White & Jamil's assertions: proper pitch rate/temp control/oxygenation, yeast will stand up better to repeated pitches. Not as big a deal for us as for pros who repitch all the time, but still; their assertion is that if any of those things are off, then it significantly reduces the number of repitches you can get out of a single pitch of yeast. If any one is significantly low, subsequent repitches can suffer from underattenuation and/or weird off flavors due to screwey ester profiles.

 

[ram5ey]

My initial thought was how I heard Chris White say WLP90 was developed as a strain that was idiot proof. I am more inclined to believe this wouldn't turn out the same with 002/1968 but maybe not. I do think the temp control is far more important.

 

[orangehero]

Another thing that might be interesting to test - but would certainly take a considerably longer period, is another of White & Jamil's assertions: proper pitch rate/temp control/oxygenation, yeast will stand up better to repeated pitches. Not as big a deal for us as for pros who repitch all the time, but still; their assertion is that if any of those things are off, then it significantly reduces the number of repitches you can get out of a single pitch of yeast. If any one is significantly low, subsequent repitches can suffer from underattenuation and/or weird off flavors due to screwey ester profiles.

I've read that if you want to repitch it's better to underpitch to stimulate reproduction so you have a larger population of new cells.

The calculators for recipes and yeast propagation are only guidelines and estimations. In a commercial brewery they learn the behavior of their yeast very intimately, and you don't need a lab for that. They (usually) aren't using the whole catalog of yeast to brew dozens of widely different styles. The homebrewer has to do the same. You have to carefully observe and learn how a particular strain behaves in your brewery with your equipment and techniques. That's the only way to make great beer consistently.

 

[stratslinger]

I've read that if you want to repitch it's better to underpitch to stimulate reproduction so you have a larger population of new cells.

The calculators for recipes and yeast propagation are only guidelines and estimations. In a commercial brewery they learn the behavior of their yeast very intimately, and you don't need a lab for that...

And what I'm trying to get at above, is that Chris White (of White Labs) and Jamil Z state the exact opposite of both your statements in their book. Jamil's a pretty reliable authority on the homebrewing side, and White is absolutely a reliable authority on yeast in general. And according to the two, the health and appropriate size of your yeast pitch has a direct influence on the long term viability of your yeast, should you decide to repitch. And their text is littered with references to using yeast labs to ensure your yeast health and pitch count. They even dedicate an entire chapter to how to build your own yeast lab at home. If it weren't key to making better beer, they wouldn't have wasted so much of their time focusing on it.

I happen to agree with your statements regarding observing yeast in your brewery and getting familiar with how it performs - but you need a place to start from when beginning to experiment with your yeast, and what better place than with the experimental observations of two accepted experts?

 

[orangehero]

And what I'm trying to get at above, is that Chris White (of White Labs) and Jamil Z state the exact opposite of both your statements in their book. Jamil's a pretty reliable authority on the homebrewing side, and White is absolutely a reliable authority on yeast in general. And according to the two, the health and appropriate size of your yeast pitch has a direct influence on the long term viability of your yeast, should you decide to repitch. And their text is littered with references to using yeast labs to ensure your yeast health and pitch count. They even dedicate an entire chapter to how to build your own yeast lab at home. If it weren't key to making better beer, they wouldn't have wasted so much of their time focusing on it.

I happen to agree with your statements regarding observing yeast in your brewery and getting familiar with how it performs - but you need a place to start from when beginning to experiment with your yeast, and what better place than with the experimental observations of two accepted experts?

What's the second statement? I'm trying to find the source but I think it was a legitimate one describing how to revitalize a culture for repitching when the parent cells' membranes are not at optimum health.

Brewing beer is a fairly forgiving process and it's not that easy to completely muck up a batch. If you're trying to make the best beer possible then it's important to understand pitching rate as a variable you can play with to get what you want.

 

[stratslinger]

Sorry - I was going on your assertions that 1) underpitching was helpful for repitches, and 2) that you don't need a lab to learn the behavior of your yeast.

I guess I disagree less on the second statement than on the first. I'll try to look up the reference tonight, but they were adamant that underpitching is a chief reason that yeast underperforms in subsequent pitches.

As to the lab - yes, you can make observations based on what you see and taste in your finished product - but again, White and Jamil Z consistently reinforce basic lab apparatus for use in measuring cell density in pitches and using that information to determine accurate pitch rates, as well as to monitor the ongoing health of your strains. I agree that such lab use is definitely not necessary - tons of us make good or even great beer without those labs - but authorities way smarter than me insist that it can be a major benefit.

 

[rayfound]

Great discussion guys and gals. Glad you're enjoying the test... and don't forget... split a batch and try for yourselves... and share the results!!

 

[rayfound]

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?

I temp Probed the starter beer, but had a fermometer on the vial batch. They tracked very close together.

 

[drumuglyknuckles]

ok ok. but what about pitching old yeast without a starter. example: i buy the discounted yeast from my supplier because it is a month over date and pitch straight into my wort. what then??
i done this a few times and the beer came out ok. in fact, i just hurled a a vial almost a year overdate into a beautiful belgian wort. lets see what comes

 

[kombat]

i buy the discounted yeast from my supplier because it is a month over date and pitch straight into my wort. what then??

You've grossly underpitched your beer, and concordantly, will get all the expected accompanying off-flavours. If you're OK with that (and you seem to be), then more power to you. But the beer would be objectively better with a "correct" pitch rate.

 

[joshesmusica]

You've grossly underpitched your beer, and concordantly, will get all the expected accompanying off-flavours. If you're OK with that (and you seem to be), then more power to you. But the beer would be objectively better with a "correct" pitch rate.

oh don't be so objective... everybody's palates are different aren't they?

 

[kombat]

oh don't be so objective... everybody's palates are different aren't they?

LOL, absolutely! I should have been clearer - I meant "objectively better" in the sense that they'd more closely adhere to the style guidelines. You may like your Czech Pilsners with a prominent green apple flavour, but according to the style guidelines, an example without said green apple will score higher, and is "objectively" better.

Maybe just not subjectively.

 

[stratslinger]

So, a brewing buddy and I recently repeated our much earlier test along very similar lines to what was originally posted - only the expected outcomes should have been magnified pretty significantly because it was done with a lager.

We brewed 10 gallons of Munich Dunkel - everything came from a common mash tun, common brew kettle, etc. Beers were fermented side-by-side in a temperature controlled ferment chamber, after being aerated with pure O2 for 60 seconds (this may have been a key factor to our outcome).

One fermenter was pitched with a Mr Malty recommended starter (I believe it was 2 smack packs in 3L of starter wort, if memory serves), while the other was pitched with a single smack pack. All smack packs had identical manufactured dates (2-3 weeks prior to brewday).

Our tasting process wasn't quite as scientific as the one the original post described - no triangle tests were involved. Instead, we did side-by-side taste tests where we told our tasting panel (roughly 20 people) absolutely nothing about the beers other than the style. Just told them these were beers we made to test a specific hypothesis, and we wanted feedback not colored by any outside info.

Of our tasters, more (4-5) believed we gave them 2 identical beers as expressed a preference for either of the beers (2-3 each way). We had an open discussion about the perceived differences in the beer, which everyone (who could pick them up) agreed were exceedingly minor.

We had one taster fail to follow instructions, and wait to taste until after we explained the difference in the two beers. As you'd probably expect, he was the only person involved (including both of us as brewers) who claimed that the properly-pitched beer was clearly the superior product and the underpitched was clearly flawed - thereby demonstrating exactly why we wanted everyone to taste before having any knowledge of the beers beyond style.

I wanted to believe that the proper-pitched beer would have some advantage. We tried this exact experiment, a few years ago, with a Bock, with almost the same outcome. There was one notable difference that time around that we didn't observe this time: on the bock, the underpitched beer had vastly longer lag time (3+ days, vs >8 hours). This time around, both beers' lag time was nearly identical.

 

[mjcoss]

Great discussion, and love seeing experimental data. Like others, I suspect that it's a complicated process with many factors (temp, strain, etc), and so at the end of the day, I have felt that making a starter doesn't hurt. It demonstrates that the yeast if viable and gives a faster startup of the fermentation process. Is it necessary, maybe not, but to me the real question is does it hurt anything? Assuming you can make a starter with proper sanitation.

Although I have to say that the experiment that I'd like to see is one where you have a series of different pitch rates going from say 1% of what the various calculators say to 100% in steps of 10%. Is there a value at which under pitching causes real harm? or will the yeast carry on with a cell count as low as 1% of the recommended value?

 

[joshesmusica]

Great discussion, and love seeing experimental data. Like others, I suspect that it's a complicated process with many factors (temp, strain, etc), and so at the end of the day, I have felt that making a starter doesn't hurt. It demonstrates that the yeast if viable and gives a faster startup of the fermentation process. Is it necessary, maybe not, but to me the real question is does it hurt anything? Assuming you can make a starter with proper sanitation.

Although I have to say that the experiment that I'd like to see is one where you have a series of different pitch rates going from say 1% of what the various calculators say to 100% in steps of 10%. Is there a value at which under pitching causes real harm? or will the yeast carry on with a cell count as low as 1% of the recommended value?

under-pitching will most certainly cause off-flavors. in the growth phase the yeast throw out all kinds of off-flavors. it's just that:
1) they will typically clean it up after fermentation is complete when there wasn't too many off-flavors thrown out there.
2) the calculators have a very high bar for what under-pitching is
3) they are also typically very skeptical when it comes to how quickly the packaged yeast cells start dying off.

go ahead and do the experiment yourself. create a 1.090 wort. pitch in one vial. report back with the results.