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Thread: Professional Forums

  1. #1
    Join Date
    Sep 2007
    Posts
    52

    Professional Forums

    Anyone know where to find soley professional brewers forum, besides Probrewer.com? Please provide some insight and any url if you have it. Thanks.

  2. #2
    Join Date
    Feb 2006
    Location
    Maine
    Posts
    10

    Maybe we don't get it

    I don't quite understand. Maybe if you gave us some insight as to why you need another forum we could help, but you could always go through MBAA.com and maybe do a little more networking there.
    Dan Rudy
    Soul Brewer
    Milly's Tavern
    Manchester, NH

    Asking someone their favorite beer style is like asking a parent to choose their favorite child, some will do it but what does it say of their character?

  3. #3
    Join Date
    Dec 2003
    Location
    US
    Posts
    13
    Okay, I'll bite. Actually quite curious about the answer now. How does hydrogen sulfide interact with stainless steel to result in sulfur dioxide off flavors?

    Admittedly, inorganic chem is not my forte. In my little world the hydrogen sulfide would have to be oxidized to produce elemental sulfur and then that would have to be reduced to produce sulfur dioxide.

    I guess I am not really clear where the stainless fits in. Under normal brewery circumstances it should not offer the redox potential. Or is that totally off base?

    It would seem that to decrease hydrogen sulfide concentrations you would either need to remove the hydrogen sulfide or remove the sulfur after the hydrogen sulfide was oxidized. Removing the hydrogen sulfide should be straight forward enough (vigorous boil/removing it from beer with carbon dioxide, etc.). Removing the sulfur would seemingly require the addition of an element or compound that would precipitate the sulfur out before it was reduced to sulfur dioxide. That could eliminate at least some of the sulfur. But what stage of production would you add it and what would you add? You mention both wort and fermentation (although reduction potential should decrease as fermentation progresses). I would guess that the majority of hydrogen sulfide would be produced during fermentation (i.e. from yeast) and a substantially smaller amount from malt sources. But I suppose the concentrations would be relative--depending on the type of yeast(s) and other fermentation characteristics.

    Also, is there no evidence of hydrogen sulfide off flavors in the finished product? From my experiences, it would seem that hydrogen sulfide is a more potent off flavor than sulfur dioxide. However, I imagine that would not be the case everywhere (especially when one can substantially control hydrogen sulfide concentration production and/or removal).

    Let me know how far off base I am with this. Really.

    I agree with you that there is a great wealth of practical knowledge on this board. I would bet that there are a number of people that could tell you (in enough detail to please an IBD/IGB/whatever examiner) how to effectively decrease hydrogen sulfide and sulfur dioxide concentrations throughout production through to the packaged product.

    However, I would not discount the scientific knowledge of this community. From engineering to chemistry, there are enough scientifically minded people here to technically answer most questions. (Hopefully one of those people will correct the chemistry in this post.) It might be that most people are too busy producing a quality product to worry about the academic details like redox potentials ("just give me clean beer"). But they are out there. I have met them. With that said, try posting your questions and see what you get. Personally, I dig the details (and find that understanding them usually relates to some practical process change later on).

    As far as whistles and bells...no subscript option in formating the text? That is old school. (Only kidding...operating quite fine without.)

    Hit me with the music.

  4. #4
    Join Date
    Sep 2007
    Posts
    52
    Diastaticus,

    Over a short period of time I have travelled to many states around my home state of Kentucky. Exploring employment opportunities (or what I thought might be employment opportunities). In my travels I would stop at any brewpub, micro or regional brewery nearby to sample their beers. In doing so with many beers fresh in my mind I began to notice two technical flaws emerging from the majority of these locations. H2S- On my tongue I have noticed that alot of the lagers and pils have not sufficiently driven off H2S during process and remains ever so subtle to a knowing palate. Of which I will explain: In an artical written by Egbert Pfisterer, Ian Richardson and Attila Soti "Control of Hydrogen Sulfide in beer with Copper Electrolysis System" they note the choice equipment material of today is stainless steel rather than copper. Of which they note ocassionally leads to an increased level of H2S concentrations in beer since elimination as CuS (Copper Sulfide) did not take place. Depending upon the character of the under lying beer the off flavor might be perceived quite noticeable. In most cases the problem was subtle but it was there. My initial thought would be to add some amount of copper to the boil kettle to eliminate such technical flaw from eventually shining through in the finished beer. The authors suggested another method which is two electrodes in a stainless steel housing controlled by power supply with an adjustment knob to allow for accurate precipitation of H2S into CuS according to Faraday's Law. Suggested placement of such unit is inline before the filtration system. Ofcourse the length of time for a vigorous boil will also play a crucial role in warding off H2S. However, a balance must be made in time to prevent the Mallard Reaction as well if color is critical to the final product. I might add that yeast influence (meaning action of and pressure under which they work) in closed conical systems will play a later role to complicate the situation but most importantly none of these beers that I have tasted have not won awards any greater than silver or high 80's scoring (Lagers and Pilsners styles).
    As for the SO2 problem this seems to be inherent to those that use a few particular strains of popular yeast in closed conical systems throughout the majority of beers they brew. I will explain this to greater detail: an underlying factor that contributes to all the beers brewed using the same strain regardless of style remains the same. The culprit-yeast. I know its not process as how many brewhouses could be using an identical process to warrant such a similar problem, therefore the problem must lie in the yeast function during its stage of process. Detectable levels of SO2 could be found in beers brewed by these companies regardless to style that they brewed a long as they used the same yeast in those styles. Why go through the trouble of using different ingredients to create a different style beer but then use one and same yeast for four to five different styles? Interestingly enough I have found that one style out of five or six beers that such companies produce will have a good score or medal for that beer but their other beers will have less scores or medals awarded for those mostly due to technical flaw in the beer. Its no wonder as to why that is. At any rate the problem not only lies with the yeast alone. There are other factors to take into consideration as well- all facets of fermentation parameters including those of the type of tank itself (closed or open, flat or conical and height to width ratios to round or square design). I did not want to make my answer too long as to bore many people so if there is issue as to part of my answer then please call me out on it and I will clairfy. Thanks.

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