Author Topic: Auf Englisch, bitte. Pitching rates and esters  (Read 5392 times)

Offline nateo

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Auf Englisch, bitte. Pitching rates and esters
« on: July 20, 2012, 08:12:32 AM »
Mein bisschen Deutsch isn't up to the task, so I was wondering if someone on here could take a look at this for me: http://d-nb.info/978186087/34

According to Kai the paper shows that increased pitching rates leads to increased ester production, so I wanted to know more about what the author is talking about.
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Re: Auf Englisch, bitte. Pitching rates and esters
« Reply #1 on: July 20, 2012, 08:52:37 AM »
I can tell you that has been verified a number of times.  Neva Parker mentioned it in her AHA seminar last June.  It came up in a question I asked to Dr. Clayton of Lallemand many years ago in HBD's "Fortnight of Yeast". (http://www.danstaryeast.com/articles/yeast-growth).  The basic mechanism is that the same enzyme, acetyl co-A, is responsible for both yeast growth and ester production.  If it's doing one, it can't do the other.  So, if you pitch the right amount of yeast, you get cell growth but reduced ester production.  If you pitch too much yeast, the enzyme produces esters because it doesn't need to work on cell growth.
« Last Edit: July 20, 2012, 10:01:22 AM by denny »
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Offline richardt

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Re: Auf Englisch, bitte. Pitching rates and esters
« Reply #2 on: July 20, 2012, 09:02:44 AM »
I can tell you that has been verified a number of times.  Neva Parker mentioned it in her AHA seminar last June.  It came up in a question I asked to Dr. Clayton of Lallemand many years ago in HBD's "Fortnight of Yeast". (http://www.danstaryeast.com/articles/yeast-growth).  The basic mechanism is that the same enzyme, acetyl co-A, is responsible for both yeast growth and ester production.  If it's doing one, it can't do the other.  So, if you pitch the right amount of yeast, you get cell growth but reduced ester production.  If you pitch too much yeast, the enzyme produces esters because it doesn't need to work on cell growth.

That's the best, and most straight-forward, explanation I've read to date regarding yeast growth and ester production.  Thanks Denny.
« Last Edit: July 20, 2012, 10:01:03 AM by denny »

Offline nateo

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Re: Auf Englisch, bitte. Pitching rates and esters
« Reply #3 on: July 20, 2012, 09:08:32 AM »
It sounds like underpitching-for-more-esters is one of those "zombie" ideas. No matter how many times people kill it, it just keeps coming back.
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Re: Auf Englisch, bitte. Pitching rates and esters
« Reply #4 on: July 20, 2012, 10:00:21 AM »
It sounds like underpitching-for-more-esters is one of those "zombie" ideas. No matter how many times people kill it, it just keeps coming back.

If you believe any number of brewing scientists, you are absolutely correct.
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Re: Auf Englisch, bitte. Pitching rates and esters
« Reply #5 on: July 20, 2012, 12:45:16 PM »
Interesting.  So this suggests under-pitching versus over-pitching for lagers is better?? Or just plain pitching the proper amount and that's that.
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Re: Auf Englisch, bitte. Pitching rates and esters
« Reply #6 on: July 20, 2012, 02:01:22 PM »
At the NHC, Neva Parker stated that the following are true. She said that there are also some recent papers from Japan that state this.

Underpitch - More fusels, less esters.
Overpitch - Less fusels, more esters.

This was challenged from the audience, as we have all read the opposite from our books. She said that it is the correct facts.
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Offline nateo

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Re: Auf Englisch, bitte. Pitching rates and esters
« Reply #7 on: July 20, 2012, 02:31:20 PM »
Underpitch - More fusels, less esters.
Overpitch - Less fusels, more esters.

That squares with my completely unscientific, anecdotal experience. It also explains why there are so many homebrewed fusel-bomb Belgian beers.
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Re: Auf Englisch, bitte. Pitching rates and esters
« Reply #8 on: July 22, 2012, 06:02:49 AM »
How long does it usually take for the presentations to get uploaded on the AHAconference.org site? I'm really interested in that Neva Parker presentation.
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Offline hoser

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Re: Auf Englisch, bitte. Pitching rates and esters
« Reply #9 on: July 22, 2012, 07:24:47 AM »
If you can't wait, my understanding is that Neva Parker's presentation on Northern Brewer/Brewing TV is fairly similar to the NHC presentation:

http://www.northernbrewer.com/connect/2012/07/neva-parker-white-labs-presentation-qa-and-new-products/


Offline hoser

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Re: Auf Englisch, bitte. Pitching rates and esters
« Reply #10 on: July 22, 2012, 07:30:57 AM »
Underpitch - More fusels, less esters.
Overpitch - Less fusels, more esters.

That squares with my completely unscientific, anecdotal experience. It also explains why there are so many homebrewed fusel-bomb Belgian beers.

There are more variables at play than just pitching rate; yeast health, pitch temperature, fermentation temperature, wort gravity, and oxygenation rate.  So, to just say that pitching rate affects everything is just the tip of the iceberg (Neva covers some of this in here video presentation, namely oxygenation).

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Re: Auf Englisch, bitte. Pitching rates and esters
« Reply #11 on: July 22, 2012, 08:54:32 AM »
There are more variables at play than just pitching rate; yeast health, pitch temperature, fermentation temperature, wort gravity, and oxygenation rate.  So, to just say that pitching rate affects everything is just the tip of the iceberg (Neva covers some of this in here video presentation, namely oxygenation).

Yeah, I try to hold a nuanced, balanced opinion. I want yeast to make flavors I like, and I don't want yeast to make flavors I don't like, and I'm open to any information that helps me accomplish that.

I sent out beer to some of the guys on this forum, and the feedback I've received has been really enlightening. I've decided I have no ability to objectively evaluate small changes in my technique. I think I'm cool and smart, with a good palate, but it turns out I'm not capable at all to discern subtle differences in the beer I make. Other homebrewers also think they're cool and smart with a good palate, so I'm really starting to doubt the veracity of some of their claims regarding subtle differences.
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Re: Auf Englisch, bitte. Pitching rates and esters
« Reply #12 on: July 22, 2012, 09:01:11 AM »
It sounds like underpitching-for-more-esters is one of those "zombie" ideas. No matter how many times people kill it, it just keeps coming back.

I think it's because lowering the pitching rate increases phenol production, and people get the two confused.
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Re: Auf Englisch, bitte. Pitching rates and esters
« Reply #13 on: July 22, 2012, 09:32:50 AM »
How long does it usually take for the presentations to get uploaded on the AHAconference.org site? I'm really interested in that Neva Parker presentation.

Kate had hoped to have them up this week.  Since that didn't happen, I'd guess they'll be there soon.
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Re: Auf Englisch, bitte. Pitching rates and esters
« Reply #14 on: July 22, 2012, 09:36:46 AM »
I sent out beer to some of the guys on this forum, and the feedback I've received has been really enlightening. I've decided I have no ability to objectively evaluate small changes in my technique. I think I'm cool and smart, with a good palate, but it turns out I'm not capable at all to discern subtle differences in the beer I make. Other homebrewers also think they're cool and smart with a good palate, so I'm really starting to doubt the veracity of some of their claims regarding subtle differences.



Too few people take this objective viewpoint.  That's why I started doing blind group tasting years ago and why I so frequently question people who say that certain things make a definite difference in their beers.
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