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-   -   Pro brewery pitch rates vs. homebrew "overpitching"? (http://www.homebrewtalk.com/f163/pro-brewery-pitch-rates-vs-homebrew-overpitching-281938/)

Piratwolf 11-18-2011 05:11 PM

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! :mug:

bottlebomber 11-18-2011 05:16 PM

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.

rockfish42 11-18-2011 05:54 PM

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

bh10 11-18-2011 07:03 PM

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.

theredben 11-18-2011 09:47 PM

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!

Pilgarlic 11-18-2011 09:59 PM

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.

rockfish42 11-18-2011 10:49 PM

Quote:

Originally Posted by Pilgarlic (Post 3498222)
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.

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.

PseudoChef 11-18-2011 10:58 PM

Quote:

Originally Posted by bottlebomber (Post 3497231)
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.

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.

jfr1111 11-18-2011 11:34 PM

Quote:

Originally Posted by PseudoChef (Post 3498399)
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.

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.

Calder 11-19-2011 02:01 AM

Quote:

Originally Posted by PseudoChef (Post 3498399)
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.

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".


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