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Re: [Distillers] Oxygen Depravation of Yeast

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  • Scott Rudy
    Didn t we have someone not that long ago brag about adding oxygen at the beginning from his oxy/acetalyne torch to get the yeast a good active base population
    Message 1 of 9 , Oct 3, 2002
      Re: [Distillers] Oxygen Depravation of Yeast Didn't we have someone not that long ago brag about adding oxygen at the beginning from his oxy/acetalyne  torch to get the yeast a good active base population to start with?


      on 10/3/02 1:40 PM, BOKAKOB at bokakob@... wrote:


      Hello, Group! I was following one of later threads called “Results of my fermentation experiment.” Many times “oxygen starving” highlighted discussions. Thinking of further advancing the subject why not to eliminate the oxygen contact altogether? I am not talking about purging the carboy with CO2   or with other gases. How about an idea of a flat impermeable plastic circular disk placed on top of the wash? Minimal gap between the circle and walls will allow the wash to foam. Will it work?



      Yet another thing just came to me. How about holding a breath for a minute or so and blowing the exhale into the carboy just before closing the stopper? Definitely it would have to be less oxygen in spent air. Still a little less...

      Cheers, Alex...


    • matthewo_brien
      Hi again all, Oxygen is needed at the start of a ferment, as while respiring aerobically, the yeast can also reproduce easily, so you can get a nice healthy
      Message 2 of 9 , Oct 3, 2002
        Hi again all,

        Oxygen is needed at the start of a ferment, as while respiring
        aerobically, the yeast can also reproduce easily, so you can get a
        nice healthy population of yeast which can then change to anaerobic
        respiration when the O2 runs out, and start converting all those
        sugars into the stuff that we really want!

        As I understand it, it is later on during the ferment that we want to
        make sure we don't get any (or much) oxygen added to the wash,
        otherwise all the yeast will swap back to aerobic respiration,
        producing stuff we *don't* want.

        The point about siphoning between fermenters is taken on board, but I
        think this is important in wine making, and beer making, where there
        *will* be further fermentation occurring in the bottled product,
        contributing largely to the flavour and alcoholic content.

        Does it matter with distilling? The ferment is finished, which means
        the sugar is used up. The yeast are basically dead. What will
        aeration of the wash do in this situation?

        My guess is not much - it is distilled within 24 hours - but like I
        said in my other email, I wonder if some higher alcohols will
        evaporate with the increase in surface area? Or oxidation of some
        compounds might be a good thing?

        Just some ideas and interesting discussion,

        Matt
      • Robert Stam
        For those who wish to know more, there is a nice little life cycle of a yeast cell page here.
        Message 3 of 9 , Oct 3, 2002
          For those who wish to know more, there is a nice little 'life cycle of a yeast cell' page here.
           
          Something they don't mention is autolysis, where in it's last attempt to survive the yeast community will begin to feed on the dead yeast carcasses. This produces some off flavours, depending on what you want of course. In Chardonnay it gives that buttery note on the palette.
          So by aerating the wash during racking, and then storing again, you run the risk of having the last remaining yeasts or their spores resurging and feeding on their ancestors. Not a great risk but something to be aware of.
           
          Cheers, Rob 

           
           
           
           -----Original Message-----
          From: matthewo_brien [mailto:mobrien@...]
          Sent: Friday, October 04, 2002 9:58 AM
          To: Distillers@yahoogroups.com
          Subject: [Distillers] Re: Oxygen Depravation of Yeast

          Hi again all,

          Oxygen is needed at the start of a ferment, as while respiring
          aerobically, the yeast can also reproduce easily, so you can get a
          nice healthy population of yeast which can then change to anaerobic
          respiration when the O2 runs out, and start converting all those
          sugars into the stuff that we really want!

          As I understand it, it is later on during the ferment that we want to
          make sure we don't get any (or much) oxygen added to the wash,
          otherwise all the yeast will swap back to aerobic respiration,
          producing stuff we *don't* want.

          The point about siphoning between fermenters is taken on board, but I
          think this is important in wine making, and beer making, where there
          *will* be further fermentation occurring in the bottled product,
          contributing largely to the flavour and alcoholic content.

          Does it matter with distilling?  The ferment is finished, which means
          the sugar is used up.  The yeast are basically dead.  What will
          aeration of the wash do in this situation?

          My guess is not much - it is distilled within 24 hours - but like I
          said in my other email, I wonder if some higher alcohols will
          evaporate with the increase in surface area?  Or oxidation of some
          compounds might be a good thing?

          Just some ideas and interesting discussion,

          Matt


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        • Mike Nixon
          Re: [Distillers] Oxygen Depravation of YeastScott Rudy wrote: Subject: Re: [Distillers] Oxygen Depravation of Yeast Didn t we have someone not that long ago
          Message 4 of 9 , Oct 3, 2002
            Re: [Distillers] Oxygen Depravation of Yeast
            Scott Rudy wrote:
            Subject: Re: [Distillers] Oxygen Depravation of Yeast

            Didn't we have someone not that long ago brag about adding oxygen at the beginning from his oxy/acetalyne  torch to get the yeast a good active base population to start with?
            =========================
            I think that was Wrombutton, but I don't think he was 'bragging' so much as simply telling us about an experiment he'd done to see what would happen.  As I recall, his advice was to stand well back!  :-))
             
            Mike N
          • Michael
            ... to ... I ... there ... means ... Hey Matt, From my understanding, 90% of any methanol present in your batch is a resultant of aerobic reproduction of
            Message 5 of 9 , Oct 3, 2002
              --- In Distillers@y..., "matthewo_brien" <mobrien@u...> wrote:
              > Hi again all,
              >
              > Oxygen is needed at the start of a ferment, as while respiring
              > aerobically, the yeast can also reproduce easily, so you can get a
              > nice healthy population of yeast which can then change to anaerobic
              > respiration when the O2 runs out, and start converting all those
              > sugars into the stuff that we really want!
              >
              > As I understand it, it is later on during the ferment that we want
              to
              > make sure we don't get any (or much) oxygen added to the wash,
              > otherwise all the yeast will swap back to aerobic respiration,
              > producing stuff we *don't* want.
              >
              > The point about siphoning between fermenters is taken on board, but
              I
              > think this is important in wine making, and beer making, where
              there
              > *will* be further fermentation occurring in the bottled product,
              > contributing largely to the flavour and alcoholic content.
              >
              > Does it matter with distilling? The ferment is finished, which
              means
              > the sugar is used up. The yeast are basically dead. What will
              > aeration of the wash do in this situation?
              >
              > My guess is not much - it is distilled within 24 hours - but like I
              > said in my other email, I wonder if some higher alcohols will
              > evaporate with the increase in surface area? Or oxidation of some
              > compounds might be a good thing?
              >
              > Just some ideas and interesting discussion,
              >
              > Matt

              Hey Matt,

              From my understanding, 90% of any methanol present in your batch is a
              resultant of aerobic reproduction of yeast. As you said, it is
              easier for the yeast to reproduce aerobically, but it is important to
              remember that it is capable of reproducing anaerobicly. I'm pretty
              sure that the yeast does not actually need oxygen to start, that just
              makes it easier. I have known a few people who use a CO2 bottle to
              fill their brew keg with CO2 when pitching the yeast and reduce the
              amount of O2 that the yeast has available.

              Mike G
            • BillyWeeble@cs.com
              In a message dated 10/3/02 10:40:47 AM Pacific Daylight Time, bokakob@yahoo.com writes: The yeast
              Message 6 of 9 , Oct 3, 2002
                In a message dated 10/3/02 10:40:47 AM Pacific Daylight Time,
                bokakob@... writes:

                << why not to eliminate the oxygen contact altogether? >>

                The yeast need to make "Daughter" cells, buds as it were, and they do
                this aerobically. The cell walls are strengthened and the yeast is more
                viable under extreme conditions such as high alcohol and low ph when allowed
                to grow for a generation or two. I'm working on a "perpetual" fermentation
                system that will allow for a constant "take" of distillable product while
                leaving the yeast (not all of it of course) and adding what the yeast needs
                to replace that which was consumed. It all starts by first aerating the yeast
                every step of the way. I'm very happy with the results so far.
                Of course the wash must become ANaerobic in order to produce ethanol and
                that happens in due time. Strong and healthy bodies will make it to the
                finish line. The CO2 lies heavy on the top of the wash and prevents O2
                infiltration as long as it's not disturbed. Some good ol' boys stir their
                mash in big vats with a boat oar but are careful not to mix in air while they
                do it.
              • Zeke Jones
                ... . How about an idea of a flat impermeable plastic circular disk placed on top of the wash? Minimal gap between the circle and walls will allow the wash to
                Message 7 of 9 , Oct 4, 2002



                  >From: BOKAKOB
                  . How about an idea of a flat impermeable plastic circular disk placed on top of the wash? Minimal gap between the circle and walls will allow the wash to foam. Will it work?

                  >Cheers, Alex...

                  I already use this on my fermenters...its called a lid....:>)

                  >
                  >
                  >
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                  ><< noxygen.gif >>


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