Author Topic: Hefe sulfur  (Read 5619 times)

Offline tschmidlin

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Re: Hefe sulfur
« Reply #15 on: August 21, 2012, 12:23:48 AM »
The guy who did the research on the history of lager yeast from South America was skyped into the BJCP reception at the NHC. Some yeasts have genes that he called the SUL1 and SUL2 sulfate transport genes, which allow the sulfate in and sulfite out - or something like that.

Maybe Tom can chime in on that, as that is in his area of expertise.
I had to look them up, but yes, SUL1 and SUL2 encode sulfate permeases (as in permeability enzyme, per-me-ase).  Good memory Jeff, I wish I could have made that presentation, I had questions :)

From SGD (http://www.yeastgenome.org/):
SUL1 - "High affinity sulfate permease of the SulP anion transporter family; sulfate uptake is mediated by specific sulfate transporters Sul1p and Sul2p, which control the concentration of endogenous activated sulfate intermediates"

SUL2 - "High affinity sulfate permease; sulfate uptake is mediated by specific sulfate transporters Sul1p and Sul2p, which control the concentration of endogenous activated sulfate intermediates"
Tom Schmidlin

Offline phillamb168

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Re: Hefe sulfur
« Reply #16 on: August 21, 2012, 02:23:06 AM »
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Offline hopfenundmalz

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Re: Hefe sulfur
« Reply #17 on: August 21, 2012, 04:26:32 AM »
The guy who did the research on the history of lager yeast from South America was skyped into the BJCP reception at the NHC. Some yeasts have genes that he called the SUL1 and SUL2 sulfate transport genes, which allow the sulfate in and sulfite out - or something like that.

Maybe Tom can chime in on that, as that is in his area of expertise.
I had to look them up, but yes, SUL1 and SUL2 encode sulfate permeases (as in permeability enzyme, per-me-ase).  Good memory Jeff, I wish I could have made that presentation, I had questions :)

My memory should not get any credit, I had looked at my notes from the conf. to find something else a day or 2 ago and saw that. Well I did remember it from a day or 2 ago.  :)

The reason I wrote that down was it explained why my lagers are sometimes a little stinky when fermenting.
Jeff Rankert
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Offline hulkavitch

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Hefe sulfur
« Reply #18 on: August 28, 2012, 09:12:22 AM »
Update: almost three weeks sulfur is not noticeable unless i rouse the yeast into the beer before i pour? Im not really believing at rhis point that sulfur cant age out.

Offline roguejim

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Re: Hefe sulfur
« Reply #19 on: August 28, 2012, 11:45:18 AM »
Q
Update: almost three weeks sulfur is not noticeable unless i rouse the yeast into the beer before i pour? Im not really believing at rhis point that sulfur cant age out.

Is that "can", or "can't" age out?

At any rate, not being able to rouse the yeast is a bummer since that is precisely what should be done before pouring a bottled Hefe.

I received an email from Eric Warner saying that he hadn't had much problem with this.  He ferments in the low 60s, under pitches, and under aerates to good effect.  Jamil told me that a vigorous fermentation from start to finish will minimze the sulphur.  So, as far as I can see, there doesn't appear to be a reliable way to prevent it, just different approaches to conditioning it out after the fact.  I wish Gordon Strong would chime in here given his NHC Gold for his El Hefe.
« Last Edit: August 28, 2012, 11:47:14 AM by roguejim »

Offline hulkavitch

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Hefe sulfur
« Reply #20 on: August 28, 2012, 04:43:10 PM »
Well the sulfur does come out a bit when the yeast is roused but it still isnt as strong as bottling day. And when i dont rouse the yeast i dont smell or taste it at all

Offline majorvices

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Re: Hefe sulfur
« Reply #21 on: August 28, 2012, 05:14:43 PM »
You shouldn't be able to taste sulfur. I have found yeast can sometimes put off a sulfur like aroma. Also, on the beers I have had sulfur problems with it can smell fine once and then, if you swirl it around the sulfur comes out of suspension and you smell it all over again.

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Offline Kaiser

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Re: Hefe sulfur
« Reply #22 on: August 28, 2012, 09:09:47 PM »
I have been researching yeast and H2S production recently since that topic interests me a lot. When brewing lagers, aging out the sulfur notes tends to be the long pole and limits shorter turn around times. Sometimes I do want a lager to be done in 4 weeks.

Here is a paper that publishes data which suggests that it is the yeast not CO2 scrubbing that reduces H2S in finished beer: https://www.jstage.jst.go.jp/article/jbb/106/3/106_3_253/_pdf

This publication also shows that the final H2S uptake doesn't happen until the beer gets close to its limit of attenuation. This is an interesting observation. It may mean that poor attenuation, i.e. the fermentation is slow to reach the attenuation limit, may go along with slow H2S reduction and the beer takes longer toe "age out" the rotten egg smell.

Kai

Offline breweite

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Re: Hefe sulfur
« Reply #23 on: August 28, 2012, 09:24:10 PM »
Thought this might help: I bottled a 3068 batch a week ago.  It sat in my primary for 3.5 weeks.  It had a very strong sulfur smell, however, because of the time that had passed, I bottled anyway.  Long story short, I over primed my bottles and I had to fridge them literally three days later.  I drank one that evening, and it was delicious and there wasn't even a hint of sulfur.  Delicious brew.  3068, although I've only used it twice, is one of the foulest smelling yeast!  All science aside, my experience is that the sulfur smell dissipates quickly in bottles.
Cheers from Austin, Tejas!

Offline tschmidlin

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Re: Hefe sulfur
« Reply #24 on: August 29, 2012, 12:25:33 AM »
Thought this might help: I bottled a 3068 batch a week ago.  It sat in my primary for 3.5 weeks.  It had a very strong sulfur smell, however, because of the time that had passed, I bottled anyway.  Long story short, I over primed my bottles and I had to fridge them literally three days later.  I drank one that evening, and it was delicious and there wasn't even a hint of sulfur.  Delicious brew.  3068, although I've only used it twice, is one of the foulest smelling yeast!  All science aside, my experience is that the sulfur smell dissipates quickly in bottles.
This could be because of the renewed fermentation caused by priming the bottles.

Also, my 3068 ferments are fine, it is one of the cleaner wheat beer strains I've tried, for whatever that is worth.
Tom Schmidlin