Pro brewery pitch rates vs. homebrew "overpitching"?

My guess is that I'm misinterpreting something along the way, but I've been thinking about this a lot since I recently started rinsing/re-using yeast consistently.

Seems like part of the consensus explanation for the speed of pro brewery fermentation is "pitching rates" and this is always stated in such a way that (perhaps erroneously) I infer that their pitch rates are much higher than homebrewers'.

OTOH, I've read any number of warnings that OVERpitching yeast in one's homebrew is just as likely to produce bad results as UNDERpitching.

These two things don't seem to add up. Of course there are other factors (yeast health/viability being tops, I think), but can anyone shed some light on this apparent disparity?

Cheers!

It doesn't add up, and isn't as straight forward as some people make it seem. Breweries are pitching large quantities of yeast, but the examples of "grain to bottle in 8 days" etc are all clean-fermented styles, IPA etc, so a lot of the negatives to overpitching don't apply. Also the big breweries are fermenting under pressure in many cases, which causes the yeast to behave differently. Of course for them, autolysis is an actual concern, where in the homebrew setting it really is not.

As far as under-pitching, this might be undesirable in an IPA, but may produce favorable results in Belgian style ales, where esters and phenols are an important part of the flavor profile. Many brewers underpitch purposely to strain the yeast and produce more esters.

Overpitched beers taste flat, a lot of the flavor even in clean styles comes from the byproducts of yeast growth.

Its not that brewers over pitch they pitch active yeast, like what homebrewers do onto a yeast cake. Again the type of yeast is important to.

It is not that commerical breweries "over-pitch" or "under-pitch", it is just different that they use a different pitch rate than homebrewers.There are three main differences between "pro" brewer's, and homebrewer's fermentations:

1. Yeast Quality - Commercial breweries have excellent quality control, including actual cell counts and viability testing (not Mr. Malty ).

2. Absolute recipe control - Commercial breweries use things like densitometers to ensure that the SG is actually what they need, not a vague hydrometer reading.

3. Fermenter shape/size - When beer is fermented in huge (1000 Gallon+) cylindro-conical tanks, the whole fermentation process happens differently. Some good, some bad, but completely different.

The other thing that commercial breweries have that homebrewers (usually) don't have is years or even decades making the same beer. Day in, day out, the same ingredients, the same beer. That level of intimateness really is not doable at the home level. We homebrewers are always seem to be making different recipes.

Really, it is not possible to replicate the commercial process at home. That doesn't bother me though, mine tastes better!

Zainasheff and White, in Yeast, hold that the negative effects of overpitching aren't manifest in the character of the resulting beer, but in the continued viability and health of the yeast over successive generations. If you're not planning on reusing multiple times, in other words, don't worry about overpitching. Disclaimer: I'm not qualified to weigh in on this matter from experience. I'm conveying, as well as I can, what I recall Zainasheff and White wrote. I do tend to give weight to Jamil's experience.

Pilgarlic said:

Zainasheff and White, in Yeast, hold that the negative effects of overpitching aren't manifest in the character of the resulting beer, but in the continued viability and health of the yeast over successive generations. If you're not planning on reusing multiple times, in other words, don't worry about overpitching. Disclaimer: I'm not qualified to weigh in on this matter from experience. I'm conveying, as well as I can, what I recall Zainasheff and White wrote. I do tend to give weight to Jamil's experience.

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They also mention unexpected or fewer esters, autolysis flavors, and poor head retention as well as increases in acetaldehyde, diacetyl and possibly lower attenuation. The room for error is larger with overpitching though.

bottlebomber said:

It doesn't add up, and isn't as straight forward as some people make it seem. Breweries are pitching large quantities of yeast, but the examples of "grain to bottle in 8 days" etc are all clean-fermented styles, IPA etc, so a lot of the negatives to overpitching don't apply. Also the big breweries are fermenting under pressure in many cases, which causes the yeast to behave differently. Of course for them, autolysis is an actual concern, where in the homebrew setting it really is not.

As far as under-pitching, this might be undesirable in an IPA, but may produce favorable results in Belgian style ales, where esters and phenols are an important part of the flavor profile. Many brewers underpitch purposely to strain the yeast and produce more esters.

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Any sources for this information? I go grain to glass in under 10 days with English styles moreso than American styles. And I think it's big misnomer to say "clean-fermented." I can "clean-ferment" a Belgian/English/Weizen and still have it contain the esters that are part of those styles.

I honestly don't think many breweries underpitch on purpose. For the styles which esters play a large part, the yeast strain should give off those esters even at the proper pitch rates. Underpitching may cause other off-flavors (resulting in a non-"clean-fermentation") as well as the possibility of incomplete fermentations. No chances that I, or any professional brewer, would really want to take, I think.

PseudoChef said:

Any sources for this information? I go grain to glass in under 10 days with English styles moreso than American styles. And I think it's big misnomer to say "clean-fermented." I can "clean-ferment" a Belgian/English/Weizen and still have it contain the esters that are part of those styles.

I honestly don't think many breweries underpitch on purpose. For the styles which esters play a large part, the yeast strain should give off those esters even at the proper pitch rates. Underpitching may cause other off-flavors (resulting in a non-"clean-fermentation") as well as the possibility of incomplete fermentations. No chances that I, or any professional brewer, would really want to take, I think.

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I do know of at least one commercial brewer up here who underpitches one of his beers to increase the phenols, but I very much doubt it is common practice.

PseudoChef said:

Any sources for this information? I go grain to glass in under 10 days with English styles moreso than American styles.

I honestly don't think many breweries underpitch on purpose. For the styles which esters play a large part, the yeast strain should give off those esters even at the proper pitch rates. Underpitching may cause other off-flavors (resulting in a non-"clean-fermentation") as well as the possibility of incomplete fermentations. No chances that I, or any professional brewer, would really want to take, I think.

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Grain to glass in 10 days, I'm impressed ( I assume you keg). I've gotten into a rhythm that even the simplest of beers will be 5 weeks before bottling, so 6 to 7 weeks to glass. I like to think I get some benefits from the extended conditioning, but I believe many English breweries have their beer in the pubs within a few weeks.

What is the definition of proper pitch rate? Mr, Malty sets the same level for every beer/yeast, I think it was based on some work by Foster. The assumptions that go into the definition may not be the best to get the best flavor from the yeast for all different types of yeast and beer styles. Supposedly Belgians 'under-pitch' to get improved esters ..... to me this is the proper pitch rate if the Commercial guys do it, and pitching per Mr.Malty could be considered to be "over-pitching".

Well, I'm of the impression that keeping a beer around for 5 weeks before you package it is completely unnecessary. Lots of people have started thinking that you need to condition your beer for these great lengths of time for it to be any good. I think these people aren't fermenting their beers correctly (which goes back to the topic of this thread) in the first place.

There's this huge thought that beers are "green" post-fermentation - but I'm of the camp that believes this "greenness" shouldn't occur in the first place. I'm not saying all my beers turn out absolutely spectacular, but I take great strides to pitch the correct amount of healthy yeast and ferment on the cooler side. Nine times out of ten, my fermentations are complete within 4-7 days. I don't taste diacetyl or acetaldehyde, even when using English strains. There's nothing wrong here, so I see no point in "conditioning." Many English strains (or derivations thereof) drop clear extremely quick (002/1968, 007/1098, 028/1728) and can be kegged/bottled after about a week. Yes, other yeast strains will take longer to drop out of solution.

Now I can't speak with much experience on bottle conditioning as the last time I did that was over 3 years ago, but Sierra Nevada has SN Pale Ale fully carbed in 7 days. Why then, is there this big issue or prevalence that homebrew bottle conditioning takes so long?

And I've yet to see any definitive evidence that breweries (Belgian or otherwise) underpitch to get these esters. I have two Dubbels (1.070) chugging along right now that both got 3 litres of starter yeast (per Mr. Malty) - I sampled yesterday and I must say that both (1762 and 3787) have significant esters present, as per style. Again, these yeasts have evolved to produce these characteristics, and I'd rather pitch a healthy dose to ensure complete fermentation than to underpitch, drive yeast stress up (possibly producing other off flavors) and risk under-attenuation.

All just my $0.02, of course.

Anyone here use BeerSmith and checked the suggested start size (w/stir plate) vs. MrMalty? MrMalty suggests a larger start size. There is a thread about this on the BeerSmith site.

PseudoChef said:

Well, I'm of the impression that keeping a beer around for 5 weeks before you package it is completely unnecessary. Lots of people have started thinking that you need to condition your beer for these great lengths of time for it to be any good. I think these people aren't fermenting their beers correctly (which goes back to the topic of this thread) in the first place.

There's this huge thought that beers are "green" post-fermentation - but I'm of the camp that believes this "greenness" shouldn't occur in the first place. I'm not saying all my beers turn out absolutely spectacular, but I take great strides to pitch the correct amount of healthy yeast and ferment on the cooler side. Nine times out of ten, my fermentations are complete within 4-7 days. I don't taste diacetyl or acetaldehyde, even when using English strains. There's nothing wrong here, so I see no point in "conditioning." Many English strains (or derivations thereof) drop clear extremely quick (002/1968, 007/1098, 028/1728) and can be kegged/bottled after about a week. Yes, other yeast strains will take longer to drop out of solution.

Now I can't speak with much experience on bottle conditioning as the last time I did that was over 3 years ago, but Sierra Nevada has SN Pale Ale fully carbed in 7 days. Why then, is there this big issue or prevalence that homebrew bottle conditioning takes so long?

And I've yet to see any definitive evidence that breweries (Belgian or otherwise) underpitch to get these esters. I have two Dubbels (1.070) chugging along right now that both got 3 litres of starter yeast (per Mr. Malty) - I sampled yesterday and I must say that both (1762 and 3787) have significant esters present, as per style. Again, these yeasts have evolved to produce these characteristics, and I'd rather pitch a healthy dose to ensure complete fermentation than to underpitch, drive yeast stress up (possibly producing other off flavors) and risk under-attenuation.

All just my $0.02, of course.

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If agree that home brew doesn't "need" this time but I feel that a better quality product can be found in a beer that has been left to age for a while. Can you make changes or adjustments to make a younger beer similar to one that has aged... Sure. Either way can make good beer. But, there is a reason master brewers hold vertical tastings. Often these beers are intended to be aged. Bottom line great beer can be made quickly or slowly, it completely depends on the brewers intension. I'd argue certain beers (big beers) need time to meld and mellow...

Underpitching won't result in underattenuation unless you're doing it to an absurd degree. It might be a bit slower, sure, but terminal gravity should be pretty much the same.

I also take pitching rates seriously, and disagree with the huge amount of people who make the SAME 1.5L (or whatever size) starters for almost all their beers, regardless of viability and the beer's OG.

But still, I see no reason to ignore the ability to manipulate the final product with different pitching rates (or oxygenation, which I also take very seriously). It's just another tool in the brewer's toolbox. My saison is just so much better when underpitching, for example. And I'll even overpitch for certain beers as well.

Keep in mind that commercial brewers are restricted by the need to make money. And low turnover loses money. In most cases, commercial breweries will sacrifice a *bit* of quality in order to get it out the door faster - be it due to overpitching, lack of conditioining, or something else. Saison Dupont, for instance, is fermented at 95°, not because it results in the best beer, but because it shortens fermentation time.

As homebrewers, most of us have the ability to let our beer have as much time as it needs to ferment and condition. It takes a bit more space, but since I already have the space available, and don't put myself in a position where I have nothing to drink, I'd rather give it any extra time it needs. A brewery could not justify a 10% boost in quality (subjective, I know) for a 50% increase in grain-to-glass time, but I personally have no problem doing it. I want to brew the absolute best stuff I possibly can.

Underpitching can, admittedly, affect yeast health so that it doesn't perform as well in future generations. I'm okay with that, and people have to decide if they are too. The beers I underpitch aren't exactly using house yeasts anyways, and if it costs me $6-7 extra (for a new vial each time) to make a better beer, it's well worth it to me. Although if I plan to use the same yeast again reasonably soon, I'll often make a starter with plenty of extra yeast and set that extra aside for starters for future brews, rather than using the yeast from the beer.

Commercial brewers have many advantages over us when it comes to brewing better be. It just seems silly to give up the few advantages that homebrewers *definitely* have.

We need to sticky emjays lymrics

yinzer2 said:

Anyone here use BeerSmith and checked the suggested start size (w/stir plate) vs. MrMalty? MrMalty suggests a larger start size.

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Jamil is absolutely obsessed with pitching tons of yeast. I have sometimes felt that Mr Malty's recommended pitching rates are somewhat excessive. I know that Jamil has probably forgotten more about brewing than I will ever know, but I have made many great beers with substantially lower pitching rates than Mr Malty suggests. Never really had any issues with under-attenuation, off flavors, etc. My beers have gotten consistently good scores in competitions, never been marked down for excessive fermentation by-products or anything. I mainly make starters to get the yeast active before pitching, not because I feel I need significantly more volume of yeast. I just figure, if it ain't broke.......well you know. But I also don't reuse a lot of yeast, and when I do it's usually only for 1 or 2 generations ( 6$ for a new WL vial is well worth it for me compared to the time and effort it takes me to wash and reuse yeast without having a conical). Someone who consistently uses and reuses the same strains for multiple generations may be a bit more concerned about higher pitching rates to avoid yeast stress.

AdamWiz said:

I have made many great beers with substantially lower pitching rates than Mr Malty suggests. Never really had any issues with under-attenuation, off flavors, etc.

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You can still make great beers by pitching less than MrMalty suggests, not even Jamil says you won't. The idea is to make them even greater (in addition to maximizing yeast health.) I noticed an improvement when I started using his those pitching rates as my baseline. They were really good to begin with, and they got even better... it's not as simple as just being either good or not good. Granted, the improvement wasn't nearly as drastic as what I experienced when I started controlling temperatures, but it was enough for me, and other people, to take notice.

And really, some beergas even improve from underpitching anyways. That's why I said I use Mr. Malty as my "baseline"... I increase or decrease the cell count by a given percentage, depending on what beer I'm brewing.

Piratwolf said:

My guess is that I'm misinterpreting something along the way, but I've been thinking about this a lot since I recently started rinsing/re-using yeast consistently.

Seems like part of the consensus explanation for the speed of pro brewery fermentation is "pitching rates" and this is always stated in such a way that (perhaps erroneously) I infer that their pitch rates are much higher than homebrewers'.

OTOH, I've read any number of warnings that OVERpitching yeast in one's homebrew is just as likely to produce bad results as UNDERpitching.

These two things don't seem to add up. Of course there are other factors (yeast health/viability being tops, I think), but can anyone shed some light on this apparent disparity?

Cheers!

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In short the misgivings and worries about overpitching yeast when homebrewing are totally overblown if not complete BS. It is next to impossible for the typical homebrewing to overpitch yeast, at least to the point where any adverse problems might be expected.

AdamWiz said:

Jamil is absolutely obsessed with pitching tons of yeast. I have sometimes felt that Mr Malty's recommended pitching rates are somewhat excessive.
<snip..>

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I think that he and everyone else is agreed on "For an ale, you want to pitch around 0.75 million cells of viable yeast (0.75 million for an ale, 1.5 million for a lager), for every milliliter of wort, for every degree plato.". I'm keying in on his growth factor for the stir plate.

sorry, i should of posted this link at the get go.

http://www.beersmith.com/forum/index.php?topic=5895.0

BigEd said:

In short the misgivings and worries about overpitching yeast when homebrewing are totally overblown if not complete BS. It is next to impossible for the typical homebrewing to overpitch yeast, at least to the point where any adverse problems might be expected.

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I really don't think it would be easy to overpitch in a homebrew setting. You'd have to put a 1.040 beer on a yeast cake I'd think to come close to gross overpitching. Even then, I doubt you'd get many adverse effects; unlike underpitching one vial of yeast in a 1.080 beer in which I'd expect to see some effects of stressed yeast.

It's true that good beer can be made with less than perfect techiques. But I would submit that great beer can not be made with underpitching and temperature control.

My English beers are usually 7-10 days in the fermenter. 3-4 days to ferment, and then a couple of days to rest. That's assuming a flocculant yeast strain and a proper yeast pitch. My other beers, most often APAs, IPAs, and ambers, are in the fermenter about 10 days before dryhopped. They are typically packaged on day 13-20 depending on my work/home schedule.

Leaving the beers in the fermenter won't harm them, and I"m glad to see that many people are discarding the old-timer's advice of getting the beer off of the yeast cake right away. But going the other extreme and saying you need 4 weeks in the fermenter and even longer in the bottle isn't what I'd like to see either.

It's true that a poorly made beer may improve with some extra time. But a well-made relatively simple beer doesn't need it.

Yooper said:

I really don't think it would be easy to overpitch in a homebrew setting. You'd have to put a 1.040 beer on a yeast cake I'd think to come close to gross overpitching. Even then, I doubt you'd get many adverse effects; unlike underpitching one vial of yeast in a 1.080 beer in which I'd expect to see some effects of stressed yeast.

It's true that good beer can be made with less than perfect techiques. But I would submit that great beer can not be made with underpitching and temperature control.

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That's the gist of what I said.

And yeah, overpitching is much more forgiving. I'm not sure any amount of overpitching could even make a good beer bad, especially those styles where you want a neutral yeast character.

However, it can have subtle impacts. It's no secret that ester production is reduced somewhat when overpitching. Sometimes you may even want that, but other times not so much. There seems to be an oft-repeated fallacy on this forum that a certain method or parameter must be best, because it's already producing good or even great beer - even "great" beer can be improved.

As for fermenting/conditioning times... there's a few styles which I tend to rush (hefes, APAs), but most styles I tend to give 4+ weeks (and another 3-4 in bottle). I'm rarely in a rush, so if I know it won't hurt, and there's even a chance it might help, I don't mind waiting. Unless it's a beer that's going to be negatively affected by being more than a couple weeks in the fermentor, I just don't see the point in focusing on going grain to glass as quick as possible.

yinzer2 said:

I think that he and everyone else is agreed on "For an ale, you want to pitch around 0.75 million cells of viable yeast (0.75 million for an ale, 1.5 million for a lager), for every milliliter of wort, for every degree plato.". I'm keying in on his growth factor for the stir plate.

sorry, i should of posted this link at the get go.

http://www.beersmith.com/forum/index.php?topic=5895.0

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I'll have to agree. Jamil's pitching rates on Mr. Malty are calculated by the accepted standard. What seems to vary a lot, and not just with Mr. Malty, is how to achieve said pitching rate. There are many factors that affect growth rates, cell counts and viability. To boast that any one method or software program provides the perfect starter with spot on pitching rates everytime is just non sense. What Mr. Malty tries to do is take all of these factors into account and error on the side of caution so that as homebrewers, we can expect to achieve at least the proper pitching rate (if not slightly over). Bottom line is, it's your job as a homebrewer to experiment and find the optimal pitching rate and starter methods that work best for your beer. Until then, you'll just have to take someone elses word for it and Mr. Malty is a good place to start.

emjay said:

Unless it's a beer that's going to be negatively affected by being more than a couple weeks in the fermentor, I just don't see the point in focusing on going grain to glass as quick as possible.

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I actually agree with you. But I'm feeling the need to mention the option to people, as it seems almost a militant like mantra around here suddenly: "Four weeks in primary at least or you beer will suck!" That's simply not true.

Some beers can possibly benefit from an ultra long primary (more than 2 weeks). Most will not benefit, but it usually can't hurt. That's the truth.

My argument is that a well made beer (proper pitch yeast, fresh ingredients, good water, proper temperature control) will never NEED that long. Once the beer has been at FG for at least three days, and it is clear, there is no advantage to simply letting it sit for the sake of letting it sit. That's the point I'm trying to make.

bottlebomber said:

Also the big breweries are fermenting under pressure in many cases, which causes the yeast to behave differently.

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This is a myth with no basis in reality. I've been to hundreds of breweries and have not seen one that ferments under pressure. Sealing the tank with a couple of degrees plato left, yes, performing the active portion of fermentation under pressure, no. It probably happens but it is certainly not a normal or popular practice.

emjay said:

Underpitching won't result in underattenuation unless you're doing it to an absurd degree. It might be a bit slower, sure, but terminal gravity should be pretty much the same.

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FWIW, page 278 of 'Yeast' indicates that underpitching can result in a stuck fermentation. It's possible that severe underpitching is neccesary for this to occur but there is no indication of degree in the book that I can see.

The bottom line is that unhealthy yeast conditions cause stuck fermentations.

You know what I'd like to see? An experiment. One 10 gallon batch, even divided between two fermenters. One would be underpitched, like using one vial in a 1.065 batch. The other, overpitched. We'd have to calculate what that is, but say 4 vials as an example. All else would remain the same- temperature, time in the fermenter, etc. At the end of 10 days, check the SG and have a blind taste test. Bottle (or keg) and have another taste test in 3 weeks.

I'm unwilling to do it for two reasons- one, I refuse to underpitch even in the interests of science and two, I would say to avoid a starter to take out the possiblity of contamination or any other variable, and I don't want to spend that much money on yeast!

But I think it would be the only way to say what the effects of underpitching vs overpitching the same batch in homebrewing do.

Yooper said:

You know what I'd like to see? An experiment. One 10 gallon batch, even divided between two fermenters. One would be underpitched, like using one vial in a 1.065 batch. The other, overpitched. We'd have to calculate what that is, but say 4 vials as an example. All else would remain the same- temperature, time in the fermenter, etc. At the end of 10 days, check the SG and have a blind taste test. Bottle (or keg) and have another taste test in 3 weeks.

I'm unwilling to do it for two reasons- one, I refuse to underpitch even in the interests of science and two, I would say to avoid a starter to take out the possiblity of contamination or any other variable, and I don't want to spend that much money on yeast!

But I think it would be the only way to say what the effects of underpitching vs overpitching the same batch in homebrewing do.

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Basic Brewing Radio did that in late 2009 in conjunction with BYO Magazine. They did one with 1/4 the recommendation, one with proper, and one with 4 times. I think they got about 10 people to do it at the same time with different beers. The odd thing was that some beers benefited from under, while some did better with over. Their conclusion was to use Mr Malty, but if you make a beer repeatedly then you should try this experiment because it seems to be yeast related which do better an which worse.

I think that the OG plays a big role... big beers will probably be affected by yeast count to a much greater extent than smaller beers. In other words, yeast proliferation can probably mask underpitching in a smaller beer but would result in stressed yeast in a bigger beer.

I've personally underpitched a 1.060 beer that scored a 35 and no off flavors in a competition. That was before I started using THE rate calculator.

So I think good beers can be had with underpitching. But good is good and better is better.

And FWIW Yooper, I am totally with you on the time before bottling/kegging. If you make a beer by the book, pitch at fermentation temps with an appropriate amount of healthy yeast and keep the wort oxygen free and fermentations temperatures without fluctuations, you do not always need 3+ weeks in the primary.

remilard said:

This is a myth with no basis in reality. I've been to hundreds of breweries and have not seen one that ferments under pressure. Sealing the tank with a couple of degrees plato left, yes, performing the active portion of fermentation under pressure, no. It probably happens but it is certainly not a normal or popular practice.

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Well, sort of.

The vessel itself isn't pressurized, correct. But there is a ton of pressure placed on the bulk of the yeast by the weight of the liquid column alone...

emjay said:

Well, sort of.

The vessel itself isn't pressurized, correct. But there is a ton of pressure placed on the bulk of the yeast by the weight of the liquid column alone...

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That's why they dump the trub.

Yooper said:

That's why they dump the trub.

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Yes, but the fact it even collects there at all indicates that a lot of the fermentation is taking place under a great deal of pressure. Heck, those conicals are so tall that the yeast doesn't even need to be on the bottom to be under a lot of pressure.

And in fact, pressure is something that can be tweaked to produce different results. Higher pressure = reduced esters. So I simulate a tall(er) conical with my blow-off tube in various depths of sanitizer. And with certain beers (like my saison), I don't even use an airlock, but rather just aluminum foil - and this was actually even recommended by Jamil.

Mr. Malty spits out 1.5 million cells x Degrree Plato/ml for lagers. Everything I've read suggests closer to .8 on commercial lager operations and I have personal success at that rate. Proper oxygen levels are every bit as important.

Personalty I think over/under pitching is any amount that dosen't get the desired results, be it culture longevity, fermantation rate or desirable esters. Using fixed numbers is giving up one of the few controls we have over yeast.

Malticulous said:

Personalty I think over/under pitching is any amount that dosen't get the desired results, be it culture longevity, fermantation rate or desirable esters.

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I think this probably says it best. I mean, if I pitch 3/4 of the recommended amount and get the results I want, who's to say I underpitched? If I pitch twice the yeast and get favorable results, who's to say I overpitched? It's only underpitching if you don't get the results you want. When I say that Mr Malty's recommendations seem excessive sometimes, I don't mean that their suggestions are too much yeast. I'm just saying that a lot of the time, basically the same results can be had without pitching as much. I believed for far too long that I would never get good fermentations unless I made huge starters. Then one brewday, I realized that I had never made a starter the day before as planned. I just pitched a single WL vial(WLP001) into 5 gallons of 1.058 wort(Amber ale), and guess what? No different than the other 2 times I had made the same beer with starters. If I can pitch less and get the same results, why wouldn't I?

Ideal rates are based on the only real objective measure there is - continued yeast health. How one decides to tweak it from there is up to the brewer.

I don't know how big your starters were, but I guarantee you that it wasn't the exact same when you pitched just a vial.

Close enough? Probably, but if you tasted them side-by-side, I assure you that you would notice the difference (assuming your palate doesn't suck, of course).

What do you mean by "ideal rates." Lagers and ales see the same yeast growth with the same rates, oxygen and nutrients. 1.5^6xPlato/ml is pushing past ideal yeast growth that I would think is at least two buddings.

Yooper said:

You know what I'd like to see? An experiment. One 10 gallon batch, even divided between two fermenters. One would be underpitched, like using one vial in a 1.065 batch. The other, overpitched. We'd have to calculate what that is, but say 4 vials as an example. All else would remain the same- temperature, time in the fermenter, etc. At the end of 10 days, check the SG and have a blind taste test. Bottle (or keg) and have another taste test in 3 weeks.

I'm unwilling to do it for two reasons- one, I refuse to underpitch even in the interests of science and two, I would say to avoid a starter to take out the possiblity of contamination or any other variable, and I don't want to spend that much money on yeast!

But I think it would be the only way to say what the effects of underpitching vs overpitching the same batch in homebrewing do.

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Saun Torell did a simple test. Temp was not consistent and many missing variables (or hard to find.)

Yeast Pitching Rate Results « SeanTerrill.com

Recipe formulation could compensate for most of the noted changes.

while the beers almost certainly are different, there is no consensus about which is better. Simply put, nearly half of people prefer under-pitched beers.

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Oddly enough--that's not his conclusion.

Malticulous said:

Oddly enough--that's not his conclusion.

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As I said later on, I think it's justifiable to discount the preferences of tasters who can't differentiate the two beers. That said, I wanted to clearly distinguish my interpretations from the actual data. Obviously you can disagree with my conclusions.

If you have questions about any "missing variables", let me know and I'll do what i can to address them.

Sean

One thing I don't understand is, why do White Labs and Wyeast advertise their products as being the proper amount to directly pitch into 5 gallons when the actual recommended pitching rates are significantly higher? Seems to me that a homebrew supplier would want to make sure that the product they are selling will deliver the best possible results when used as directed. I know White Labs mentions making a starter on their label, but it doesn't say that it is necessary or even recommended. They just say something like "if desired, a starter can be made". Why not make bigger vials?

Even with bigger vials you would still run into the potential problem of age, poor handling, etc. and therefore making a starter would still be called for. You can certainly pitch those vials into a small beer with great results and even get "beer" with a larger OG, but in the end a starter works best in most cases. As to the concern about advertising the products, I'd have to agree that they don't really hit the brewer in the face with BOLD print telling you to do a starter.

I agree with those that question the Mr Malty pitching rates. I generally don't go with the recommendations to the full extent. For a 6 gallon batch even when it calls out for 2 vials, I just do a larger single no-step up starter and have had great results that way.

The subject of pro vs. home brew pitch rates is certainly one that I'd love to know the real answer to, I'm staying tuned in.

samc said:

The subject of pro vs. home brew pitch rates is certainly one that I'd love to know the real answer to, I'm staying tuned in.

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I think that pro brewer's large pitching rates are mostly to increase fermentation speed and for the viability/repitchability of yeast with constant multi-generation use. Their main concerns are getting beer through the fermenters quickly and making sure their yeast is not stressed at all so they can continually reuse it. These 2 things are not nearly as important to homebrewers who don't need to rush production to make money and don't need to worry about cost cutting as much by repitching for many generations. For a pro brewer though, it is VERY important to be able to extensively reuse yeast to cut costs. They can't just buy a 6$ White Labs vial like us. I only reuse yeast from my lightest and lowest gravity beers, and even then for only a couple generations. I would rather spend an extra 6 bucks than risk mutated, contaminated, or overly stressed yeast messing up a batch.