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vinegar = acetic acid

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  • Tony & Elle Ackland
    Just realised another reason not to use vinegar to acidify the wash with. Vinegar is acetic acid. The July 2000 newsletter on the Altech page,
    Message 1 of 4 , Feb 22, 2001
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      Just realised another reason not to use vinegar to acidify the wash with.

      Vinegar is acetic acid.

      The July 2000 newsletter on the Altech page,
      http://www.alltech-bio.com/alcohol.htm reckons that acetic acid in
      concentrations of more than 0.05% will kill the yeast.

      0.05% of 20L is only 10 mL

      Tony
    • Tony & Elle Ackland
      ... etc...? Don t know. The only other acid listed by them as a stress on the yeast is lactic acid, which should be kept below 0.8% w/v. This is
      Message 2 of 4 , Feb 24, 2001
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        >Question: if acetic acid kills the yeast, why not citric, hyrochloric,
        etc...?

        Don't know. The only other acid listed by them as a "stress" on the yeast
        is lactic acid, which should be kept below 0.8% w/v. This is significant
        if recycling backset, as it can build up over time. If there's bacteria
        present (particularly Lactobacillus), then quite a lot can be made real
        easy, and quickly become a problem.

        It must be a function of how that particular acid interacts with the yeast,
        and the various intermediate products during the formation of ethanol &
        growth, rather than just a problem with "acidity".

        There is also a "citric acid" cycle for the synthesis of intermediate
        compounds while the yeast is using the glucose to get some energy. Don't
        quite understand it fully, not being a microbiologist, so don't know its
        implications, but generally the yeast is capable of making many different
        organic acids while having their fun.
      • Ted Palmer
        These two acids are organic acids while others like phosphoric and nitric are mineral acids. I don t remember why they interfere with cell metabolism but they
        Message 3 of 4 , Feb 24, 2001
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          These two acids are organic acids while others like phosphoric and nitric are mineral acids. I don't remember why they interfere with cell metabolism but they do pose a problem.
          Tony was that .05% acetic a typo? In this post it is .8% lactic which is a pH of less than 2!! No wonder that it stresses the yeast.
          _____________
          Ted Palmer
          tpalmer@...
          ----- Original Message -----
          Sent: Saturday, February 24, 2001 12:41 AM
          Subject: RE: [Distillers] vinegar = acetic acid


          >Question: if acetic acid kills the yeast, why not citric, hyrochloric,
          etc...?

          Don't know.  The only other acid listed by them as a "stress" on the yeast
          is lactic acid, which should be kept below 0.8% w/v.  This is significant
          if recycling backset, as it can build up over time.  If there's bacteria
          present (particularly Lactobacillus), then quite a lot can be made real
          easy, and quickly become a problem.

          It must be a function of how that particular acid interacts with the yeast,
          and the various intermediate products during the formation of ethanol &
          growth, rather than just a problem with "acidity".

          There is also a "citric acid" cycle for the synthesis of intermediate
          compounds while the yeast is using the glucose to get some energy.  Don't
          quite understand it fully, not being a microbiologist, so don't know its
          implications, but generally the yeast is capable of making many different
          organic acids while having their fun.


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        • Tony & Elle Ackland
          ... Nope, thats what it says. 0.05 % w/v What pH is that ? Tony
          Message 4 of 4 , Mar 3, 2001
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            >Tony was that .05% acetic a typo?

            Nope, thats what it says. 0.05 % w/v
            What pH is that ?

            Tony
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