Author Topic: Auf Englisch, bitte. Pitching rates and esters  (Read 5475 times)

Offline nateo

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Re: Auf Englisch, bitte. Pitching rates and esters
« Reply #15 on: July 22, 2012, 11:08:04 AM »
lowering the pitching rate increases phenol production

I haven't heard that before. Do you have a link to your source for that? I've been poking around on Google looking for more info, and came across this: http://www.scientificsocieties.org/jib/papers/1996/1996_102_5_327.pdf which I found interesting, but they didn't mention pitching rate's influence.

Surprisingly, a large amount of 4-VG is formed during the boil, and Weizen yeasts have only a weak ability to decarboxylate ferulic and cinnamic acid. It does appear that a ferulic acid rest at 45*C really does make a difference, though, so I'm surprised by that.

"the formation of 4-VG continued at steady rates throughout the boil" < This might be why in Eric Warner's German Wheat book he recommends a 2-hour boil.
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Offline hopfenundmalz

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Re: Auf Englisch, bitte. Pitching rates and esters
« Reply #16 on: July 22, 2012, 11:30:30 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).

Neva was going over homebrew myths about yeast, and was directly addressing the one about a lower pitch rate causing more esters. Of course there is more to it than just pitch rates as you listed, and one could include yeast strain to that list.
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Offline roguejim

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Re: Auf Englisch, bitte. Pitching rates and esters
« Reply #17 on: July 22, 2012, 11:42:25 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.

Like decocting lagers, right?  I think that was one of your taste tests...Didn't some in the group actually prefer single infused over decocted lagers?

Offline nateo

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Re: Auf Englisch, bitte. Pitching rates and esters
« Reply #18 on: July 22, 2012, 12:11:39 PM »
Like decocting lagers, right?  I think that was one of your taste tests...Didn't some in the group actually prefer single infused over decocted lagers?

I'm still waiting on a couple results, so I won't comment until all the feedback is in, but I'm sure there will be a lively discussion once I've sorted through the responses and put the results up on the forums.

Edit: Were you talking about Denny's decoction study? It was mostly single-decoction vs regular mashing, IIRC, though he left that up to the individual brewers to decide. It was also a range of beers, if I remember correctly. The "preferred infused" and "no preference" taken together were the majority opinion, though there were a slight preference for the decocted beers over the infused beers. The conclusion Denny drew was that decoction doesn't produce a beer that's clearly preferred, which I think is fair.

I'm not sure about the breakdown of individual choices, and how many people sampled which beers. Just from the chart I saw, it's possible about half the people preferred the decocted beers every time, and the other half preferred the infused every time. If people preferred, say, one infused, and a different decocted, with no significant trend in preference, then that would be clear support for Denny's conclusion.
« Last Edit: July 22, 2012, 12:28:28 PM by nateo »
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Offline denny

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Re: Auf Englisch, bitte. Pitching rates and esters
« Reply #19 on: July 22, 2012, 12:31:55 PM »
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.

Like decocting lagers, right?  I think that was one of your taste tests...Didn't some in the group actually prefer single infused over decocted lagers?

Yep.  and if you add together those who preferred the non decocted beers and those who had no preference, it was more than preferred the decocted beers.
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