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Re: Aeration

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  • jamesonbeam1
    No Gavin, Not really kills.. You can not over oxygenate in the first 24 hours. This is during the yeasts exponential growth phase which is aerobic and they
    Message 1 of 30 , Mar 25, 2011
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      No Gavin,

      Not really kills..  You can not over oxygenate in the first 24 hours.  This is during the yeasts' exponential growth phase which is aerobic and they need all the O2 they can get.  After that, they enter the stationary phase which is an anaerobic phase when the ethanol is produced and no growth happens.

      As Dr. Reines states:

      "In terms of fermentation, aeration is also important but only in the early stages (first 6-24 hours).  Aeration in later stages can oxidize beer constituents and lead to the development of off-flavors.  Since aeration sets the stage for maltose fermentation and alcohol tolerance, it is easy to envision why insufficient aeration could lead to stuck fermentations or incomplete fermentations.  Incomplete fermentations can be manifested as either high finishing gravities or the production of off-flavors especially diacetyl, acetaldehyde, and hydrogen sulfide.  Insufficient aeration is also associated with excessive ester formation.  The profound effect of aeration on yeast is further illustrated in studies where yeast from a poorly aerated beer was repitched into aerated wort and still did not perform well.  Thus insufficient aeration can have a long-lasting effect on yeast. 

       

      In general, it is difficult for homebrewers to achieve sufficient oxygen levels.  The levels of oxygen necessary for optimal fermentation vary depending on the yeast strain.  Ale strains usually need between 8-12 part per million (ppm) while lager strains require slightly higher amounts (10-15 ppm).  At atmospheric pressure the maximum level of dissolved oxygen in wort is approximately 8 ppm and the saturation level decreases further as the gravity of the wort increases.  Thus unless special steps are taken to introduce air or oxygen into the wort, it is difficult for homebrewers to achieve adequate aeration.  Recent studies have shown that oxygenation is by far more efficient than aeration.  Injection of oxygen through a 2 micron diffusing stone can actually supersaturate the wort with 10-12 ppm of dissolved oxygen being reached in 5 gallons of wort by a single 60 second blast of oxygen! "  http://maltosefalcons.com/tech/yeast-propagation-and-maintenance-principles-and-practices

      JB. aka Waldo.


      --- In new_distillers@yahoogroups.com, "gavinflett" <gavin_flett@...> wrote:
      >
      > Does anyone think it's possible to aerate the wash too much to the point where it kills the ferment?
      >

    • Gavin Flett
      So it may be as I had originally suspected, my wash has simply fermented out quicker than expected.. After reading that I would have say woops. It seems I am
      Message 2 of 30 , Mar 25, 2011
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        So it may be as I had originally suspected, my wash has simply fermented out quicker than expected..

        After reading that I would have say woops. It seems I am again misinformed as to the aerobic and anaerobic phases of the fermentation. In my attempt at making sure the wash had sufficient aeration (plus thinking that yeast growth can occur at least through the 48 hr period) I syphoned it from carboy to carboy twice (one each day) and making sure it had plenty of splash to try and get the oxygen in the mix plus mixing it to get the mash cap down etc, etc..... The yeast I am using is I think W-Yeast and it's a whiskey yeast from my local brew shop and i have experimented with varying temperatures with so far less than pleasing results. I am making my way up to an average temperature of 29C as i had begun in the low 20'sC

        However the oldest batch I have aging right now is about 9 months. I have grown to like drinking 18 and 21 year scotch, so perhaps I have set the bar a bit high, however my goal is still to at least match those. The trouble I am having is, how do I know my product now will turn out delicious in 10, 12, 15 18 years. If anyone can let me know that I will be grategully indebted.

        One more thing, how can I guage how many ppm of oxygen I am getting in my wash?


        To: new_distillers@yahoogroups.com
        From: jamesonbeam1@...
        Date: Fri, 25 Mar 2011 11:44:49 +0000
        Subject: [new_distillers] Re: Aeration

         

        No Gavin,
        Not really kills..  You can not over oxygenate in the first 24 hours.  This is during the yeasts' exponential growth phase which is aerobic and they need all the O2 they can get.  After that, they enter the stationary phase which is an anaerobic phase when the ethanol is produced and no growth happens.
        As Dr. Reines states:

        "In terms of fermentation, aeration is also important but only in the early stages (first 6-24 hours).  Aeration in later stages can oxidize beer constituents and lead to the development of off-flavors.  Since aeration sets the stage for maltose fermentation and alcohol tolerance, it is easy to envision why insufficient aeration could lead to stuck fermentations or incomplete fermentations.  Incomplete fermentations can be manifested as either high finishing gravities or the production of off-flavors especially diacetyl, acetaldehyde, and hydrogen sulfide.  Insufficient aeration is also associated with excessive ester formation.  The profound effect of aeration on yeast is further illustrated in studies where yeast from a poorly aerated beer was repitched into aerated wort and still did not perform well.  Thus insufficient aeration can have a long-lasting effect on yeast. 

         

        In general, it is difficult for homebrewers to achieve sufficient oxygen levels.  The levels of oxygen necessary for optimal fermentation vary depending on the yeast strain.  Ale strains usually need between 8-12 part per million (ppm) while lager strains require slightly higher amounts (10-15 ppm).  At atmospheric pressure the maximum level of dissolved oxygen in wort is approximately 8 ppm and the saturation level decreases further as the gravity of the wort increases.  Thus unless special steps are taken to introduce air or oxygen into the wort, it is difficult for homebrewers to achieve adequate aeration.  Recent studies have shown that oxygenation is by far more efficient than aeration.  Injection of oxygen through a 2 micron diffusing stone can actually supersaturate the wort with 10-12 ppm of dissolved oxygen being reached in 5 gallons of wort by a single 60 second blast of oxygen! "  http://maltosefalcons.com/tech/yeast-propagation-and-maintenance-principles-and-practices

        JB. aka Waldo.


        --- In new_distillers@yahoogroups.com, "gavinflett" <gavin_flett@...> wrote:
        >
        > Does anyone think it's possible to aerate the wash too much to the point where it kills the ferment?
        >


      • Ed Barcik
        Would there be any benefit to aeration using ozone which is O3
        Message 3 of 30 , Mar 26, 2011
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          Would there be any benefit to aeration using ozone which is O3

        • wilypig@gmail.com
          Snip ... O3 is an aggressive oxidizer that will adversely affect the product. O3 is used as a sterilizing agent and will damage yeast and will lead to stale
          Message 4 of 30 , Mar 26, 2011
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            Snip

            >
            > Would there be any benefit to aeration using ozone which is O3


            O3 is an aggressive oxidizer that will adversely affect the product. O3 is used as a sterilizing agent and will damage yeast and will lead to stale flavors in the finished product.
          • bruich44
            ... Using oxygen through a .5 micron ss stone I have been very happy with 60 seconds on a normal beer and 90 seconds on a big beer. If you re
            Message 5 of 30 , Mar 26, 2011
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              > One more thing, how can I guage how many ppm of oxygen I am getting in my wash?


              Using oxygen through a .5 micron ss stone I have been very happy with 60 seconds on a normal beer and 90 seconds on a big beer. If you're shaking/splashing the carboy, you can do it until you get tired.

              One thing I wanted to add was Wyeast did a presentation a few years back at our beer club meeting and when making a big beer (or wash if you will) say 14% and over, they strongly recommended aerating the wort on up to 2 minute oxygen blasts through a stone periodically in the initial stages of fermentation. Their testing found no off-flavors in the final beer so long as all added aeration was stopped by 50% of your expected final gravity. So if you have a 1.120 wort, you could effectively continue aerating it until you reach .070 or so, if you expect it to end around 1.010.
            • Gavin Flett
              That s outstanding information, thanks for that To: new_distillers@yahoogroups.com From: bruichladdich44@gmail.com Date: Sat, 26 Mar 2011 15:31:56 +0000
              Message 6 of 30 , Mar 26, 2011
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                That's outstanding information, thanks for that


                To: new_distillers@yahoogroups.com
                From: bruichladdich44@...
                Date: Sat, 26 Mar 2011 15:31:56 +0000
                Subject: [new_distillers] Re: Aeration

                 

                > One more thing, how can I guage how many ppm of oxygen I am getting in my wash?

                Using oxygen through a .5 micron ss stone I have been very happy with 60 seconds on a normal beer and 90 seconds on a big beer. If you're shaking/splashing the carboy, you can do it until you get tired.

                One thing I wanted to add was Wyeast did a presentation a few years back at our beer club meeting and when making a big beer (or wash if you will) say 14% and over, they strongly recommended aerating the wort on up to 2 minute oxygen blasts through a stone periodically in the initial stages of fermentation. Their testing found no off-flavors in the final beer so long as all added aeration was stopped by 50% of your expected final gravity. So if you have a 1.120 wort, you could effectively continue aerating it until you reach .070 or so, if you expect it to end around 1.010.


              • jamesonbeam1
                Gavin, Only time will tell for your whiskey (if you can wait that long [;)] )... As far as testing for oxygen in your fermentation, all aquarium stores for
                Message 7 of 30 , Mar 27, 2011
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                  Gavin,

                  Only time will tell for your whiskey (if you can wait that long ;))...

                  As far as testing for oxygen in your fermentation, all aquarium stores for fish have O2 testing kits that work just like a pH testing kit where you add chemicals and see what the color is,

                  JB. aka Waldo.


                  --- In new_distillers@yahoogroups.com, Gavin Flett <gavin_flett@...> wrote:
                  >
                  >
                  > So it may be as I had originally suspected, my wash has simply fermented out quicker than expected..
                  > After reading that I would have say woops. It seems I am again misinformed as to the aerobic and anaerobic phases of the fermentation. In my attempt at making sure the wash had sufficient aeration (plus thinking that yeast growth can occur at least through the 48 hr period) I syphoned it from carboy to carboy twice (one each day) and making sure it had plenty of splash to try and get the oxygen in the mix plus mixing it to get the mash cap down etc, etc..... The yeast I am using is I think W-Yeast and it's a whiskey yeast from my local brew shop and i have experimented with varying temperatures with so far less than pleasing results. I am making my way up to an average temperature of 29C as i had begun in the low 20'sC
                  > However the oldest batch I have aging right now is about 9 months. I have grown to like drinking 18 and 21 year scotch, so perhaps I have set the bar a bit high, however my goal is still to at least match those. The trouble I am having is, how do I know my product now will turn out delicious in 10, 12, 15 18 years. If anyone can let me know that I will be grategully indebted.
                  > One more thing, how can I guage how many ppm of oxygen I am getting in my wash?

                • Gavin Flett
                  Once again, thanks for the info! To: new_distillers@yahoogroups.com From: jamesonbeam1@yahoo.com Date: Sun, 27 Mar 2011 13:10:22 +0000 Subject:
                  Message 8 of 30 , Mar 27, 2011
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                    Once again, thanks for the info!


                    To: new_distillers@yahoogroups.com
                    From: jamesonbeam1@...
                    Date: Sun, 27 Mar 2011 13:10:22 +0000
                    Subject: [new_distillers] Re: Aeration

                     

                    Gavin,
                    Only time will tell for your whiskey (if you can wait that long ;))...
                    As far as testing for oxygen in your fermentation, all aquarium stores for fish have O2 testing kits that work just like a pH testing kit where you add chemicals and see what the color is,
                    JB. aka Waldo.

                    --- In new_distillers@yahoogroups.com, Gavin Flett <gavin_flett@...> wrote:
                    >
                    >
                    > So it may be as I had originally suspected, my wash has simply fermented out quicker than expected..
                    > After reading that I would have say woops. It seems I am again misinformed as to the aerobic and anaerobic phases of the fermentation. In my attempt at making sure the wash had sufficient aeration (plus thinking that yeast growth can occur at least through the 48 hr period) I syphoned it from carboy to carboy twice (one each day) and making sure it had plenty of splash to try and get the oxygen in the mix plus mixing it to get the mash cap down etc, etc..... The yeast I am using is I think W-Yeast and it's a whiskey yeast from my local brew shop and i have experimented with varying temperatures with so far less than pleasing results. I am making my way up to an average temperature of 29C as i had begun in the low 20'sC
                    > However the oldest batch I have aging right now is about 9 months. I have grown to like drinking 18 and 21 year scotch, so perhaps I have set the bar a bit high, however my goal is still to at least match those. The trouble I am having is, how do I know my product now will turn out delicious in 10, 12, 15 18 years. If anyone can let me know that I will be grategully indebted.
                    > One more thing, how can I guage how many ppm of oxygen I am getting in my wash?


                  • brzdistiller
                    I ve seen a lot of people advising the use of an aquarium pump and stone, but was wondering how one goes about cleaning that porous stone? I ve been using a
                    Message 9 of 30 , Apr 6, 2011
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                      I've seen a lot of people advising the use of an aquarium pump and stone, but was wondering how one goes about cleaning that porous stone?

                      I've been using a blender or hand mixer to aerate my starter for a few minutes before pitching the yeast. After the yeast is introduced, I let it work for 24 hours in this mixture of sugar water and tomato paste than add it to the mash.

                      Is this enough?
                    • Harry
                      ... Don t use an ordinary stone. They re glued together. They will fall apart with exposure to alcohol. You need one of these...
                      Message 10 of 30 , Apr 6, 2011
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                        --- In new_distillers@yahoogroups.com, "brzdistiller" <brzdistiller@...> wrote:
                        >
                        > I've seen a lot of people advising the use of an aquarium pump and stone, but was wondering how one goes about cleaning that porous stone?


                        Don't use an ordinary stone. They're glued together. They will fall apart with exposure to alcohol. You need one of these...
                        http://www.homebrewing.com/equipment/stainless-steel-air-stone.php
                        >
                        > I've been using a blender or hand mixer to aerate my starter for a few minutes before pitching the yeast. After the yeast is introduced, I let it work for 24 hours in this mixture of sugar water and tomato paste than add it to the mash.
                        >
                        > Is this enough?
                        >

                        I use 100gm yeast granulated to start a 60 litre ferment. I take a 2 litre jug, add 300-400 ml of 40C water, and 100ml of my prepared wort. Then add the yeast, dissolve it (use your hand to squeeze it into the liquid). Let it set for about 10 minutes and it will fill the 2-litre jug with froth. This is what I pitch into the wort. Then bag it or airlock it, your choice.

                        The rationale is to re-hydrate the dried granulated yeast using a weak mixture of the wort environment it is to work in (too strong will shock the yeast), and have it warm enough to rapidly absorb the moisture and activate.

                        It never fails with DGY, but don't do it with turbos. If using turbos, always follow maker's instructions.


                        Slainte!
                        regards Harry
                      • Alli
                        In this business more than many the devil is in the details. When areating for 4-6 hours after the yeast has been pitched, how does one keep the air borne
                        Message 11 of 30 , Aug 30, 2011
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                          In this business more than many the devil is in the details. When areating for 4-6 hours after the yeast has been pitched, how does one keep the air borne wild yeast out of the mash? I thought of putting the lid on the fermentor and running the air hose through the hole for the airlock, but that might restrict the air flow in/out of the vessel. Just wordering how other folks do this. Thanks.
                          Alli
                        • Bob Glicksman
                          In winemaking, the wort is sulfated so that sulpher dioxide gas is released and kills the wild yeast, bacteria, and other undersireable organisms. Wine yeast
                          Message 12 of 30 , Aug 30, 2011
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                            In winemaking, the wort is sulfated so that sulpher dioxide gas is released and kills the wild yeast, bacteria, and other undersireable organisms.  Wine yeast is bred to tolerate higher levels of sulfates than do wild varieties.  Use sodium bisulfate (campden tablets) or potassium metabisulfate power.  These are availabe in any wine/beermaking store.



                            -----Original Message-----
                            From: Alli <allibugger@...>
                            To: new_distillers <new_distillers@yahoogroups.com>
                            Sent: Tue, Aug 30, 2011 9:05 am
                            Subject: [new_distillers] Aeration

                             
                            In this business more than many the devil is in the details. When areating for 4-6 hours after the yeast has been pitched, how does one keep the air borne wild yeast out of the mash? I thought of putting the lid on the fermentor and running the air hose through the hole for the airlock, but that might restrict the air flow in/out of the vessel. Just wordering how other folks do this. Thanks.
                            Alli

                          • Ric Cunningham
                            When aerating you are shooting for a fast start to the Yeast fermentation to out compete other organisms. This should not be an issue if using a large healthy
                            Message 13 of 30 , Aug 30, 2011
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                              When aerating you are shooting for a fast start to the Yeast fermentation to out compete other organisms. This should not be an issue if using a large healthy active yeast pitch. No Sulfate required. traditionally a grain mash is allowed to ferment with some souring agent (sour mash) but a fast yeast start will minimize that. No worries. 

                              On Tue, Aug 30, 2011 at 10:44 AM, Bob Glicksman <bobg542492@...> wrote:
                               

                              In winemaking, the wort is sulfated so that sulpher dioxide gas is released and kills the wild yeast, bacteria, and other undersireable organisms.  Wine yeast is bred to tolerate higher levels of sulfates than do wild varieties.  Use sodium bisulfate (campden tablets) or potassium metabisulfate power.  These are availabe in any wine/beermaking store.





                              -----Original Message-----
                              From: Alli <allibugger@...>
                              To: new_distillers <new_distillers@yahoogroups.com>
                              Sent: Tue, Aug 30, 2011 9:05 am
                              Subject: [new_distillers] Aeration

                               
                              In this business more than many the devil is in the details. When areating for 4-6 hours after the yeast has been pitched, how does one keep the air borne wild yeast out of the mash? I thought of putting the lid on the fermentor and running the air hose through the hole for the airlock, but that might restrict the air flow in/out of the vessel. Just wordering how other folks do this. Thanks.
                              Alli




                              --
                              If you can make macaroni and cheese from a box, you can make a great beer.
                            • Derek Hamlet
                              Small Point but they are metabisulfites, not metabisulphates. Two different animals. Also, (and this is just me). I sulfite my wines immediately after
                              Message 14 of 30 , Aug 30, 2011
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                                Small Point but they are metabisulfites, not metabisulphates. Two
                                different animals.
                                Also, (and this is just me). I sulfite my wines immediately after
                                crushing to kill any wild yeasts. But I wait 24 hours before
                                pitching my good yeast.
                                I may be all wrong but when distilling I prepare my sulfited wort,
                                aerate the daylights out of it for 8 hours before pitching my
                                yeast. The aeration will add the oxygen and also disperses the
                                metabi (I aim for 25ppm) so it is pretty much gone into the air when
                                I pitch my yeast. For the most part I also use killer yeasts that
                                are strong enough to kill any wild (usually weaker) yeasts.
                                At 09:58 AM 8/30/2011, you wrote:
                                >
                                >
                                >When aerating you are shooting for a fast start to the Yeast
                                >fermentation to out compete other organisms. This should not be an
                                >issue if using a large healthy active yeast pitch. No Sulfate
                                >required. traditionally a grain mash is allowed to ferment with some
                                >souring agent (sour mash) but a fast yeast start will minimize that.
                                >No worries.

                                Derek
                                I've traveled a long way
                                And some of the roads weren't paved
                              • JD
                                cover it with a wet towel. putt the airhose between the lid and tun. greets
                                Message 15 of 30 , Aug 30, 2011
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                                  cover it with a wet towel.
                                  putt the airhose between the lid and tun.

                                  greets

                                  --- In new_distillers@yahoogroups.com, "Alli" <allibugger@...> wrote:
                                  >
                                  > In this business more than many the devil is in the details. When areating for 4-6 hours after the yeast has been pitched, how does one keep the air borne wild yeast out of the mash? I thought of putting the lid on the fermentor and running the air hose through the hole for the airlock, but that might restrict the air flow in/out of the vessel. Just wordering how other folks do this. Thanks.
                                  > Alli
                                  >
                                • JerryM
                                  I aeration necessary if you are pitching trub? Thanks.
                                  Message 16 of 30 , Jan 19, 2013
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                                    I aeration necessary if you are pitching trub? Thanks.
                                  • Fredrick Lee
                                    Aeration is always needed. The yeast cells will consume oxygen and end up cloning themselves. Sometime shortly after the oxygen runs out, they start fuckin,
                                    Message 17 of 30 , Jan 19, 2013
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                                      Aeration is always needed. The yeast cells will consume oxygen and end up cloning themselves. Sometime shortly after the oxygen runs out, they start fuckin, which leads to mutations. The more mutation, the less control you have, the less chance you'll make that one amazing recipe again.  I would use oxygenated yeast no more than 11 generations. 

                                      On Jan 19, 2013, at 3:28 PM, "JerryM" <jkmccull@...> wrote:

                                       

                                      I aeration necessary if you are pitching trub? Thanks.

                                    • o1bigtenor
                                      ... Why 11? D
                                      Message 18 of 30 , Jan 19, 2013
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                                        On Sat, Jan 19, 2013 at 7:29 PM, Fredrick Lee <fredrick@...> wrote:


                                        Aeration is always needed. The yeast cells will consume oxygen and end up cloning themselves. Sometime shortly after the oxygen runs out, they start fuckin, which leads to mutations. The more mutation, the less control you have, the less chance you'll make that one amazing recipe again.  I would use oxygenated yeast no more than 11 generations. 


                                        Why 11?                       D
                                      • RLB
                                        Most of my reading suggests no more than 10 generations.  They hint that yeast burns out after 10 generation.  It s still there, but it s weaker against wild
                                        Message 19 of 30 , Jan 19, 2013
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                                          Most of my reading suggests no more than 10 generations.  They hint that yeast burns out after 10 generation.  It's still there, but it's weaker against wild yeast and bacteria.

                                          Robert



                                          From: o1bigtenor <o1bigtenor@...>
                                          To: new_distillers@yahoogroups.com
                                          Sent: Saturday, January 19, 2013 11:21 PM
                                          Subject: Re: [new_distillers] Aeration

                                           


                                          On Sat, Jan 19, 2013 at 7:29 PM, Fredrick Lee <fredrick@...> wrote:


                                          Aeration is always needed. The yeast cells will consume oxygen and end up cloning themselves. Sometime shortly after the oxygen runs out, they start fuckin, which leads to mutations. The more mutation, the less control you have, the less chance you'll make that one amazing recipe again.  I would use oxygenated yeast no more than 11 generations. 


                                          Why 11?                       D


                                        • Fredrick Lee
                                          Even with aeration, the main fermentation phase causes enough mutations that after the 11th generation, flavor traits are significantly altered. After 16
                                          Message 20 of 30 , Jan 20, 2013
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                                            Even with aeration, the main fermentation phase causes enough mutations that after the 11th generation, flavor traits are significantly altered. After 16 generations, the yeast cells are nearly indistinguishable from the original.  That said, there are breweries that have thousands of generations on their strains, the yeast can adapt to a system and become a "house strain." Usually attenuation suffers, or lag time or some trade off occurs from the original strain, but if it works for you, then go for it. Just don't expect consistent results. 


                                            On Jan 19, 2013, at 11:21 PM, o1bigtenor <o1bigtenor@...> wrote:

                                             



                                            On Sat, Jan 19, 2013 at 7:29 PM, Fredrick Lee <fredrick@...> wrote:


                                            Aeration is always needed. The yeast cells will consume oxygen and end up cloning themselves. Sometime shortly after the oxygen runs out, they start fuckin, which leads to mutations. The more mutation, the less control you have, the less chance you'll make that one amazing recipe again.  I would use oxygenated yeast no more than 11 generations. 


                                            Why 11?                       D

                                          • o1bigtenor
                                            ... 11 things have changed too much. Then you say that after 16 generations there is no change. Sorry only one of the foregoing can be true. D
                                            Message 21 of 30 , Jan 20, 2013
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                                              On Sun, Jan 20, 2013 at 7:06 AM, Fredrick Lee <fredrick@...> wrote:


                                              Even with aeration, the main fermentation phase causes enough mutations that after the 11th generation, flavor traits are significantly altered. After 16 generations, the yeast cells are nearly indistinguishable from the original.  That said, there are breweries that have thousands of generations on their strains, the yeast can adapt to a system and become a "house strain." Usually attenuation suffers, or lag time or some trade off occurs from the original strain, but if it works for you, then go for it. Just don't expect consistent results.

                                              Sorry - - I asked why 11 generations and you responded its because after 11 things have changed too much. Then you say that after 16 generations there is no change. Sorry only one of the foregoing can be true.                  D

                                            • Fredrick Lee
                                              No after 16 it s changed so much that the strains are completely different you can barely even tell they were related without mitochondrial DNA testing.
                                              Message 22 of 30 , Jan 20, 2013
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                                                No after 16 it's changed so much that the strains are completely different you can barely even tell they were related without mitochondrial DNA testing. 




                                                On Jan 20, 2013, at 8:12 AM, o1bigtenor <o1bigtenor@...> wrote:

                                                 



                                                On Sun, Jan 20, 2013 at 7:06 AM, Fredrick Lee <fredrick@...> wrote:


                                                Even with aeration, the main fermentation phase causes enough mutations that after the 11th generation, flavor traits are significantly altered. After 16 generations, the yeast cells are nearly indistinguishable from the original.  That said, there are breweries that have thousands of generations on their strains, the yeast can adapt to a system and become a "house strain." Usually attenuation suffers, or lag time or some trade off occurs from the original strain, but if it works for you, then go for it. Just don't expect consistent results.

                                                Sorry - - I asked why 11 generations and you responded its because after 11 things have changed too much. Then you say that after 16 generations there is no change. Sorry only one of the foregoing can be true.                  D

                                              • o1bigtenor
                                                ... So how do the big breweries get consistent results with high replication numbers yeasts? D
                                                Message 23 of 30 , Jan 20, 2013
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                                                  On Sun, Jan 20, 2013 at 7:14 AM, Fredrick Lee <fredrick@...> wrote:


                                                  No after 16 it's changed so much that the strains are completely different you can barely even tell they were related without mitochondrial DNA testing.

                                                  Thank you for clarifying!

                                                  So how do the big breweries get consistent results with high replication numbers yeasts?                            D

                                                • Fredrick Lee
                                                  ... 1.) House strains become accustomed to their environment and a certain flavor profile develops, but the yeast strains will continue to mutate until the
                                                  Message 24 of 30 , Jan 20, 2013
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                                                    So how do the big breweries get consistent results with high replication numbers yeasts?                            D 

                                                    1.) House strains become accustomed to their environment and a certain flavor "profile" develops, but the yeast strains will continue to mutate until the most beneficial mutations are established.  Breweries with house strains must have consistent processes and ingredients to ensure the strain remains consistent as possible.

                                                    2.) Large breweries (and even small ones like ours) maintain a yeast lab where they keep a library of pure cultures of the strains (in sealed test tubes called slants). When the 11th batch goes out the door on the production line, the yeast lab prepares another pure strain from a slant on a Petri dish or culture flask, and subsequently grow it up until its big enough to pitch. In our case we grow it up to about 10 gallons, and pitch it into ~300 gallons.  What comes off that 300 gallon tank is used about 10 more times. Myself and our brewmaster (and a few others) can start noticing a very subtle change in the flavor around generations 5-6. The gas chromatograph in our lab also shows these differences, but 99% of people will not be able to tell, or if they can tell, it's not too much of a difference that they'll think the beer is defective. 

                                                    3.) Somewhere during the culturing phase, we'll select the colony from a petri dish and make a dozen or so new slants.  People also sell and trade slants.  This way, we can have access to hundreds of strains from all over the world.  



                                                    On Jan 20, 2013, at 9:38 AM, o1bigtenor <o1bigtenor@...> wrote:

                                                     



                                                    On Sun, Jan 20, 2013 at 7:14 AM, Fredrick Lee <fredrick@...> wrote:


                                                    No after 16 it's changed so much that the strains are completely different you can barely even tell they were related without mitochondrial DNA testing.

                                                    Thank you for clarifying!

                                                    So how do the big breweries get consistent results with high replication numbers yeasts?                            D

                                                  • RLB
                                                    Most people don t raise their own yeast, so they don t worry about aeration.  At $0.99 per a 5g pack of yeast almost makes it not worth the effort of raising
                                                    Message 25 of 30 , Jan 20, 2013
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                                                      Most people don't raise their own yeast, so they don't worry about aeration.  At $0.99 per a 5g pack of yeast almost makes it not worth the effort of raising your own yeast.

                                                      Robert



                                                      From: Fredrick Lee <fredrick@...>
                                                      To: "new_distillers@yahoogroups.com" <new_distillers@yahoogroups.com>
                                                      Sent: Sunday, January 20, 2013 8:14 AM
                                                      Subject: Re: [new_distillers] Aeration

                                                       
                                                      No after 16 it's changed so much that the strains are completely different you can barely even tell they were related without mitochondrial DNA testing. 




                                                      On Jan 20, 2013, at 8:12 AM, o1bigtenor <o1bigtenor@...> wrote:

                                                       


                                                      On Sun, Jan 20, 2013 at 7:06 AM, Fredrick Lee <fredrick@...> wrote:


                                                      Even with aeration, the main fermentation phase causes enough mutations that after the 11th generation, flavor traits are significantly altered. After 16 generations, the yeast cells are nearly indistinguishable from the original.  That said, there are breweries that have thousands of generations on their strains, the yeast can adapt to a system and become a "house strain." Usually attenuation suffers, or lag time or some trade off occurs from the original strain, but if it works for you, then go for it. Just don't expect consistent results.

                                                      Sorry - - I asked why 11 generations and you responded its because after 11 things have changed too much. Then you say that after 16 generations there is no change. Sorry only one of the foregoing can be true.                  D



                                                    • ballard_bootlegger
                                                      In short: No. :-)
                                                      Message 26 of 30 , Jan 23, 2013
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                                                        In short: No. :-)

                                                        --- In new_distillers@yahoogroups.com, "gavinflett" wrote:
                                                        >
                                                        > Does anyone think it's possible to aerate the wash too much to the point where it kills the ferment?
                                                        >
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