Author Topic: Pitching rate effects (experimental results)  (Read 6655 times)

Offline a10t2

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Pitching rate effects (experimental results)
« on: May 09, 2010, 09:52:28 PM »
I (and some very generous volunteers from the NB forum) recently conducted an experiment to determine what, if any, impact under-pitching would have on a beer. The results more or less conform to the conventional wisdom - slower fermentation, increased off-flavors, etc. I know a lot of people, especially new brewers, question the need for starters, and I think the tasters' results make a pretty persuasive case for using them.

Yeast Pitching Rate Results
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Offline tom

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Re: Pitching rate effects (experimental results)
« Reply #1 on: May 10, 2010, 09:16:24 AM »
That is fantastic. Thanks for the indepth analysis.
Brew on

Offline glitterbug

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Re: Pitching rate effects (experimental results)
« Reply #2 on: May 10, 2010, 09:28:13 AM »
That is fantastic. Thanks for the indepth analysis.

+1000
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Offline richardt

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Re: Pitching rate effects (experimental results)
« Reply #3 on: May 10, 2010, 09:43:21 AM »
Thanks for the post.  It humbly reminds us that it is the yeast that make the beer.

I used to think doing a yeast starter was overkill (Erlenmeyer flasks, stir plates, test tubes, etc.) and an unnecessary expense.
I thought, "What's the difference if I pitch one cell or 100 Billion--it will eventually multiply and ferment the beer and finish the same?"

I was only half right--the FG finishes the same, but it doesn't taste the same. 
Use a starter to ensure you have enough healthy yeast to do the job right.

Now, I just need to get my fermentation fridge set up to ensure the yeast have optimal temperatures in which to do their work...

Offline bluesman

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Re: Pitching rate effects (experimental results)
« Reply #4 on: May 10, 2010, 09:43:28 AM »
I experienced this first hand when I first started brewing many years ago. This is a testament to the fact.

Really nice work!
Ron Price

Offline majorvices

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Re: Pitching rate effects (experimental results)
« Reply #5 on: May 10, 2010, 09:52:51 AM »
this will provide a valuable link for the nay sayers and/or beginners who question the need for a starter. Thanks!
Keith Y.
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Offline denny

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Re: Pitching rate effects (experimental results)
« Reply #6 on: May 10, 2010, 11:24:23 AM »
I think I preferred the underpitched beer if I read the results correctly!   :-[
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Offline dbeechum

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Re: Pitching rate effects (experimental results)
« Reply #7 on: May 10, 2010, 11:32:00 AM »
Very nice.. I tossed a link to it up on the Falcons website.
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Offline abraxas

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Re: Pitching rate effects (experimental results)
« Reply #8 on: May 10, 2010, 11:37:28 AM »
9/30 testers could correctly identify the underpitched sample.

I wonder if this is related to about 25% of the population being "Supertasters"?
http://en.wikipedia.org/wiki/Supertaster

It would be interesting to see if there was a correlation between their tasting/brewing experience level and correct identification.
« Last Edit: May 10, 2010, 02:36:26 PM by abraxas »

Offline denny

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Re: Pitching rate effects (experimental results)
« Reply #9 on: May 10, 2010, 11:40:38 AM »
It would be interesting to see if there was a correlation between there tasting/brewing experience level and correct identification.

Not in my case!   :(
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Offline glitterbug

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Re: Pitching rate effects (experimental results)
« Reply #10 on: May 10, 2010, 11:43:11 AM »
I think I preferred the underpitched beer if I read the results correctly!   :-[

From the article:
Based on the relative frequencies of some words, I think one can reasonably conclude that the under-pitched beer was perceived to be more bitter, more astringent, more solventy, less sweet, and – bizarrely – cleaner than the beer using the standard rate. Obviously, the increased perception of negative characteristics makes a persuasive case for the use of higher pitching rates.



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Offline denny

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Re: Pitching rate effects (experimental results)
« Reply #11 on: May 10, 2010, 11:55:29 AM »
I think I preferred the underpitched beer if I read the results correctly!   :-[

From the article:
Based on the relative frequencies of some words, I think one can reasonably conclude that the under-pitched beer was perceived to be more bitter, more astringent, more solventy, less sweet, and – bizarrely – cleaner than the beer using the standard rate. Obviously, the increased perception of negative characteristics makes a persuasive case for the use of higher pitching rates.

Cleaner and more bitter were the 2 attributes I detected that made me prefer the underpitched beer.  To me, the properly pitched one seemed "flabby".
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Offline narvin

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Re: Pitching rate effects (experimental results)
« Reply #12 on: May 10, 2010, 12:12:54 PM »
What was the OG of the Amber?  Also, what type of aeration was used?  There are definitely a lot of factors at play when it comes to ester production, so although it is always a good idea to pitch "enough" healthy yeast, it would be interesting to know what other parameters were used in this specific case when looking at the results.
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Re: Pitching rate effects (experimental results)
« Reply #13 on: May 10, 2010, 12:28:57 PM »
Nice experiment and, even better, a detailed write-up of how you arrived at your conclusions. The large number of tasters who were not able to tell a difference or preferred the underpitched beer reminded me of my Kraeusen skimming experiment. But for that I did not have as many tasters as you had.

One thing to note, which I also noticed in other pitching rate experiments, was that underpitched beers don’t necessarily end up being more estery and fruity than beers pitched with more yeast. There is a lot written in home brewing literature that suggests that underpitching leads to fruity beers.

Kai

Offline denny

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Re: Pitching rate effects (experimental results)
« Reply #14 on: May 10, 2010, 12:56:00 PM »
One thing to note, which I also noticed in other pitching rate experiments, was that underpitched beers don’t necessarily end up being more estery and fruity than beers pitched with more yeast. There is a lot written in home brewing literature that suggests that underpitching leads to fruity beers.

Kai


I agree completely with this.  I often cite Dr. Clayton Cone of Lallemand who says that beers with lower pitching rates should be less estery.
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