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Thread: how are fusel alcohols formed?

  1. #1
    Join Date
    Nov 2010
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    7

    how are fusel alcohols formed?

    I've read on the internet that a low pH level, high temperature and to low nitrogen (small amounts of FAN) content in the wort can result in the formation of (fusel) higher alcohols such as 1-propanol.

    My question is: how, and why are they formed on cellular level?

    *edit*
    I've got another question: is it possible to raise the concentration of vitamins and minerals in the wort by just adding a supplement for humans? And if so, has anyone ever tried this and if so, did you notice a difference?

    *edit*

    thanks,


    Steven
    Last edited by stevencor; 11-21-2010 at 03:26 PM.

  2. #2
    http://aem.asm.org/cgi/content/full/...&pmid=18281432

    I wouldn't go adding human vitamins. The yeast pretty much get everything they need from the water and the grain. A little bit of trub is all they need.

    Your yeast will do great when you build up a healthy, active pitch of yeast, pitched into a well aerated wort, and you maintain proper temperature control. Yes, there is such a thing as yeast nutrient which are great for use in starters, but not necessary in the beer. Cider and mead DO need yeast nutrients, as there is a distinct lack of these nutrients in juice and honey.

    HTH-
    -B'Dawg

    Give a man a beer and he'll waste an hour. Teach him to brew and he'll waste a lifetime. - Nuco Gordo

  3. #3
    Join Date
    Nov 2010
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    thanks BrewDog for the link.

    I have got a question about the diagram on that page: if NADH H+ reacts with the aldehyde formed in the decarboxylation reaction, isn't the alcohol then formed? (is it possible they messed up the arrows?)

    because if you ask me, adding a hydrogen atom to an aldehyde (a carbon chain with a double bound oxygen atom, and a hydrogen atom on the 'tail'), you will get an alcohol (the double bound oxygen will create a bond with the added hydrogen, resulting in an OH group)

    (sorry for the strange sentences, have some difficulty talking about chemistry in english)


    http://aem.asm.org/cgi/content/full/74/8/2259/F1

    thanks for the quick reaction

  4. #4
    Join Date
    Nov 2010
    Posts
    7
    Nobody knows?

    I will try a biology forum.

    If anyone is interested in the answer, I will post it here..

    Thanks anyway.

  5. #5
    Please let us know. I'm not a chemist, so I couldn't tell you.
    -B'Dawg

    Give a man a beer and he'll waste an hour. Teach him to brew and he'll waste a lifetime. - Nuco Gordo

  6. #6
    Join Date
    May 2006
    Posts
    3,695
    See pages 106-110 of the late George Fix's book Principles of Brewing Science.
    On deck: a clone of Carolina Beer Co's Rye Stout, clone of Breckenridge's Vanilla Porter,
    Primary: Schwarzbier
    Secondary: Dortmunder, Hopweizen
    Keg Conditioning: Dunkelweizen, Roggenbier, Okto, Ord. Bitter
    On tap: Alt, Hefeweizen, Cigar City Maduro clone, Mild
    Bottled: Mead, Quad Rajet, Granola Bar Braggot

    Too much of everything is just enough.
    - J. Garcia

  7. #7
    Join Date
    Nov 2010
    Posts
    7
    well, the answer is child simple: they messed up the arrows and they left H2O out of the reactions.

    this explains the formation of the fusel acid on the left.

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