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  • Stuck Fermentation

    I am begging for the wise and experienced ones of this forum to ensconce me with their knowledge.

    I always thought this 'stuck fermentation' thing was something that happened to everyone else. I guess I am now everyone else....

    The krauzen seemed quite thin (may just have been foam from stirring up the wort) the first couple of days but did then build up some rich foaminess. I dont use a bubbler so cant gauge activity like that. The OG was 1.050, and after a week the FG was in the 1.022 to 1.025 range and has just hovered there ever since (now at 10 days) On a 4.5kg grain bill I had about 3.8kg pale malt and 0.4kg malted wheat. I did use that new U1/132 hops for the first time. It currently tastes more bitter than it should and still quite sweet and yet quite an alcoholic taste. The hops fruitiness seems quite strong. So at this stage I dont specifically know if something is wrong, but all indicators say yes, and I can only assume what I have is a stuck fermentation, even though:
    • Same US05 yeast i have used many times
    • Same ferment temps I always use with US05
    • Yeast was i think less than 6 months old, and stored in the fridge
    • Yeast was rehydrated and showed definite foaming activity
    • On a 4.5kg grain bill I had about 3.8kg pale malt and 0.4kg malted wheat.


    Things that I could guess could be causes:
    • Its possible the yeast could have frozen in the fridge, that sometimes slightly freezes milk etc, and damage/ killed yeast cells?
    • I did use a different thermometer in checking the mash but it still correlated closely with the temps on my STC. Even so, massively high or low temps should still give more that ~50% fermentable sugars? Shouldnt it?
    • Maybe i put rat pellets in instead of hop pellets, but hopefully this is not a factor.
    • I did get all ingredients from a new supplier I havent used before, but quality all looked good.
    • Maybe lack of oxygenation. I topped up the bucket with 2L of water which I poured from a height, and then stirred as aggressively as possible. So not the best way to oxygenate, but it definately wasnt forgotten


    So next step is fixing it. Can anyone recommend what is the best action to take? Everything I am reading says "act quickly". My concerns are:
    • Adding more yeast, I would have to oxygenate the wort again which might affect the already part fermented beer?
    • If I add more yeast and dont oxygenate again, it may make things worse?
    • I dont have more US05 yeast so I would be adding a different yeast. Would this be a problem? It would probably be a generic morgans yeast, that has been well stored
    • Apart from increasing temps a bit to 'help the yeast along', I dont know what other options I have.


    TIA
    Cheers,
    Lang
    ~~~~~~~~~~~~~~
    "Dudddde...Hold my beer!".... ; "I wonder what will happen if I ...."

  • #2
    I'm going to go with the questionable yeast theory on this, pitch more if you have or can find. Different yeast will give different flavor, but will ferment the sugars into alcohol. Guess you're not buying yeast from your new supplier again

    Sent from my SM-G935F using Tapatalk

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    • #3
      Sold me! Thanks. That's what I'm going to do. In fairness I can't remember if the yeast sachet was one of the newly bought ones or from my fridge. I guess viability of yeast received via courier delivery is always a lottery.
      Cheers,
      Lang
      ~~~~~~~~~~~~~~
      "Dudddde...Hold my beer!".... ; "I wonder what will happen if I ...."

      Comment


      • #4
        A few questions:

        How long did it take for the Kreuzen to form?

        What was your fermentation temperature?

        When you re-hydrate your yeast, how long do you leave it before pitching?

        Comment


        • #5
          As always relax dont panic and dont act in haste. 1 or 2 more days at the current state are not going to make a massive difference.

          1st step to take when you have a stuck fermentation is to do a forced fermentation test. Google is your friend ;-)

          2nd problem solve your fermentation looking at sanitation, mashing, yeast viability, O2, nutrient availability, temp and time. Then decide what to do.


          Sent from my SM-G930F using Tapatalk
          Harhm
          Senior Member
          Last edited by Harhm; 19 February 2019, 13:26.
          2017 SANHC-Finals-German Pilsner.2019 Academy of Taste-1st Lager +1st Overall-German Leichtbier.2019 Free State Fermenters-1st Place-Australian Sparkling Ale.2019 SANHC-Final Round-German Leichtbier.2020 SANHC-Top 5-EishBock.2021 SANHC-Low Alcohol Cat: 2nd-2%Lager, Over All Cat: 2nd-Schwarzbier.2022 Free State Fermenters-1st-American light Lager.2022 Fools and Fans National Competition-Top 5-Dunkles Bock

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          • #6
            Well, ever since that report by Fermentis about not needing O² or rehydration on their yeast, I dont focus on doing either anymore.

            So going by the words from their mouths, I dont think your problem should be a lack of those 2 factors.

            Tap off about 2L of your wort in a sanitised vessel & then add a little of that Morgans yeast ... I wouldn't even oxigenate ... just see what happens in a day or 2 .... the leftover wort should be fine on the yeast cake until you decide if more yeast will do the trick.

            If that 2L doesn't take off, well then it could be that there is more unfermentable sugars that what you originally thought ?? maybe much higher mash than what the equipment stated?

            Not sure who else agrees, but that's the steps I would go with .... someone else might have better option, but I suppose you're pushed for time and anxious to get it sorted.

            keep us posted.
            JIGSAW
            Senior Member
            Last edited by JIGSAW; 19 February 2019, 15:34.
            The Problem With The World Is That Everyone Is A Few Drinks Behind.!

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            • #7
              A few questions:

              How long did it take for the Kreuzen to form?
              -I think it was about 3 days when I noticed the proper thick head

              What was your fermentation temperature?
              -Set at 19 deg. Wort went into chamber at about 22 deg and got down to temp within half a day

              When you re-hydrate your yeast, how long do you leave it before pitching?
              -I typically start my rehydrating once my wort is boiling, and stir it every 10 minutes until i pitch, which is typically an hour and a half later. [Im not really sure how much foamy activity it should have after that time. Maybe it wasnt showing enough life even then]

              I'm interested to see where you are going with this.
              Cheers,
              Lang
              ~~~~~~~~~~~~~~
              "Dudddde...Hold my beer!".... ; "I wonder what will happen if I ...."

              Comment


              • #8
                Ok, thanks... a few options to consider while not rushing into anything. Will measure again tonight and see where its at
                Cheers,
                Lang
                ~~~~~~~~~~~~~~
                "Dudddde...Hold my beer!".... ; "I wonder what will happen if I ...."

                Comment


                • #9
                  Originally posted by JIGSAW View Post
                  Well, ever since that report by Fermentis about not needing O² or rehydration on their yeast, ....
                  Wow, okay. Take that John Palmer!

                  Anyways, thanks for all the advice. I tapped off just half a litre of wort-beer (see what I did there?:drunk... Also had a taste (tasting a lot more "cleaner and finished" than before), and then filled up my sample vessel while rehydrating some yeast, and took a density measurement....

                  Turns out it was a real rookie error, and forgetting my own protocols: Hydrometer reading was....... Drumrollllll... 1.010
                  And I have always only used the refractometer to monitor when the density has stabilized, not for actual values. I guess this time I lost focus on what I was doing and took the actual readings too seriously! Also, I always knew a refractometer does not work correctly on beer but damn, never realised it was so far out. (Recall it's been reading about 1.022)

                  Anyway, lesson learnt, school fees paid.

                  Thanks for the help

                  PS. While I had the cabinet all open I did my full dry hopping as planned anyway, and kept separate my little tapped sample, but in the cabinet. It will just be nice to compare dry hopped batch vs not.

                  On the hopping note... There was one pellet of hops left in the bag when I was done, which I popped in my mouth to taste. Boom... The bitterness of a thousand malaria tablets, and not even 2 glasses of milk could neutralise it fast enough. I can't believe those theories that dry hopping only adds negligible bitterness.?!?
                  Langchop
                  Senior Member
                  Last edited by Langchop; 20 February 2019, 06:19.
                  Cheers,
                  Lang
                  ~~~~~~~~~~~~~~
                  "Dudddde...Hold my beer!".... ; "I wonder what will happen if I ...."

                  Comment


                  • #10
                    Good show, have you checked the 4th edition John Palmer? Just asking, I haven't but am constantly amazed at new research etc. My first few brews weren't aerated at all and still fermented out.

                    Technically, dry hopping can reduce IBUs as the isomerized alphas are absorbed from your solution back into the hop. I have yet to find some kind of ratio or equation to apply to different dry hop schedules and varying alpha content.

                    Popping a hop pellet straight into the pie hole is not something you do twice

                    Sent from my SM-G935F using Tapatalk

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                    • #11
                      Glad to hear it was only a "rookie" error that slipped thru the cracks
                      The Problem With The World Is That Everyone Is A Few Drinks Behind.!

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                      • #12
                        Originally posted by groenspookasem View Post
                        have you checked the 4th edition John Palmer? Just asking, I haven't but am constantly amazed at new research etc.
                        No, I havent but like you say, I am regularly hearing of 180 degree changes of opinion. I think brewing is continuously moving away from "if its always been like this then it must be right" thinking, which is awesome.


                        Originally posted by groenspookasem View Post
                        Technically, dry hopping can reduce IBUs as the isomerized alphas are absorbed from your solution back into the hop. I have yet to find some kind of ratio or equation to apply to different dry hop schedules and varying alpha content.
                        Did you have to go and do that!? ... make it even more complicated


                        Originally posted by groenspookasem View Post
                        popping a hop pellet straight into the pie hole is not something you do twice
                        Actually done it many times. Some people never learn.
                        Cheers,
                        Lang
                        ~~~~~~~~~~~~~~
                        "Dudddde...Hold my beer!".... ; "I wonder what will happen if I ...."

                        Comment


                        • #13
                          I may be in the wrong here, but AFAIK yeast should be pitched within 30 minutes of rehydrating. Apparently that's the amount of food and stuff they include in the packet for the yeast - about 30 minutes' worth. I HIGHLY doubt that's the reason, but maybe it's something to keep in mind.

                          What are the chances that it could be the hops? That new experimental hops?

                          Comment


                          • #14
                            As Toxxyc says, you should pitch within 30 minutes of re-hydrating otherwise you can compromise the viability of your yeast.

                            The process for drying yeast has developed dramatically over the years so that direct pitching is now fine for most beers. I would still rehydrate for lagers and high gravity ales though.

                            My question on time for the Kreuzen to develop was to get an idea of your yeast vitality and viability. If it had taken a long time to develop that would be an indication of yeast health being compromised, which could lead to incomplete fermentation.

                            My question on fermentation temperature was to establish if you might have had fluctuations which could cause the yeast to prematurely flocculate before completing fermentation. A solution to this would be to rouse the yeast and raise fermentation temps.

                            All this seems to not be the case though. Just an incorrect gravity reading. That correction factor for alcohol when using a hydrometer has stumped many brewers. Glad you figured it out and that the beer seems to have turned out well.

                            Comment


                            • #15
                              Found the below on HBT referring to feedback from Danstar wrt rehydrating time. So I think you guys are right, probably starving yeasty bugs that took some time to get their mojo back. In comparison I rehydrated for around 1 to 1.5 hours! I also didnt know dry yeast packages actually included an amount of nutrients, but it would seem a good idea.

                              Posted Dec 9, 2012:
                              ncbrewer
                              I emailed Danstar about yeast timing. The answer was: “Our technical manager suggests that you don't go longer than 30 minutes after the start of rehydration before pitching the yeast into wort as the yeast needs nutrients. If there is a delay you could actually add more wort to the rehydration water to give the yeast something to eat while you are waiting to pitch it, so long as it isn't too hot.” I avoid having a delay by having the rehydration complete 10 – 15 minutes after the wort is ready for it.


                              I agree that it's probably fine, but I feel like the better you treat your yeast, the better it will treat you.



                              Cheers,
                              Lang
                              ~~~~~~~~~~~~~~
                              "Dudddde...Hold my beer!".... ; "I wonder what will happen if I ...."

                              Comment

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