Stuck Fermentation: to rack or not to rack?

Discussion in 'Homebrewing' started by hreb, Jun 15, 2014.

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  1. hreb

    hreb Pooh-Bah (1,748) Mar 4, 2005 Washington
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    I have had this problem several times now, especially with wheat beers, and I wonder if there is something wrong with my process. My current batch is a Witbier (or Saison) with a Safbrew T-58 starter. O.G. 1.067, within hours it was violently bubbling, and within a couple days it was down to 1.026, but then it just stopped. There's now a lot of trub at the bottom of the carboy and leftover krausen at the top and I'm really tempted to rack. I plan on bottle conditioning these so it is important to me that the fermentation "complete" before bottling, which I would expect would be somewhere below 1.018 at the highest. But reading around the internet it seems there is a lot of advice these days suggesting I shouldn't rack unless I'm actually planning to add new fermentables to a second fermentation, since it decreases yeast count and risks contamination unnecessarily. But I've also been told that racking is a good way to oxygenate beer and thus restart fermentation as long as I carry over some of the yeast from the top of the trub.

    So should I rack this beer or no? Oxygenate just by stirring or some other way? Or should I just wait it out, in which case, until when? Suppose for the sake of argument the beer has been at 1.026 for the past 3 days without any airlock activity.
     
  2. ssam

    ssam Pundit (973) Dec 2, 2008 California

    At this point, it isn't called oxygenating, its called oxidizing, and its bad. You don't want to introduce oxygen now that its fermented. The major problem people have with racking to secondary is it increases the likelihood for oxidation. The decreasing yeast count is not a problem, and contamination is easy to avoid with proper sanitation techniques. Oxidation is the only real thing to worry about, and is also not so bad if you use good technique. Really fresh beer, like homebrew, take some time for the off flavors from oxidation to set in, so if you drink a batch relatively quickly you probably will never taste oxidation. So, racking is up to you. People on this site will say don't do it. Witbiers are good with some haze so the clarifying aspects of secondary are not necessary. It won't help your gravity get down.
     
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  3. hreb

    hreb Pooh-Bah (1,748) Mar 4, 2005 Washington
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    What makes you so confident there was enough oxygen dissolved in the wort to begin with? Obviously oxidization is a risk, but if the initial supply of oxygen dissolved in the wort has been fermented away before all the sugars have been processed, fermentation will slow or stop prematurely, which also seems like a problem.
     
  4. slusk

    slusk Initiate (0) Sep 28, 2009 Virginia

    The way oxygenation works is the fresh pitch of yeast utilize the O2 in their growth phase to help cell health and prepare them for the fermentation process. After the O2 is consumed the yeast begin to chow down. If you pitched enough cells and oxygenated enough and provided the correct temps, all goes well. When there's a breakdown then you may get a stalled fermentation. As was eluded to, O2 after fermentation has begun is not a good thing unless it's a high gravity brew and you want to give another bit of O2 soon after fermentation starts. I've read about this process, never done it. But it needs to be done early in the fermentation.

    As far as racking, I myself do not. IMO there are more negatives than positives depending on other factors. I don't believe that a stuck fermentation is an indicator of a need to rack to secondary. If anything you are getting off of the yeast that has stalled which magnifies the problem. Usually within the first 3-4days, your flavor profile is set and you are into the clean up phase of fermentation. If it were me, I'd be inclined to give it a light stir once or twice a day for a few daysto try to get some yeast back into suspension and let it go longer. Maybe even raise the temps a couple of degrees.
     
    #4 slusk, Jun 15, 2014
    Last edited: Jun 15, 2014
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  5. FATC1TY

    FATC1TY Pooh-Bah (2,502) Feb 12, 2012 Georgia
    Pooh-Bah


    You need oxygen in the beer pre fermentation to assist in the growth phase. Once it's fermenting, the growth phase is over, and you don't want anymore oxygen in there.



    You mention a starter... are you making starters with dry yeast? Theres no need to do so.

    I would leave it alone.

    Also.. extract or all grain? Something is amiss in your process perhaps, such as the making a starter with dry yeast. What kind of pitching rate are you assuming?
     
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  6. VikeMan

    VikeMan Grand Pooh-Bah (3,043) Jul 12, 2009 Pennsylvania
    Pooh-Bah Society

    Why suppose that? Did you actually measure it three days apart? (Airlock activity is not a measure of gravity change/non-change.)
     
  7. Tebuken

    Tebuken Initiate (0) Jun 6, 2009 Argentina

    From Daniel J. Leonard :

    How to Beat the Stuck Fermentation Monster


    1. The Wait and See Approach: This is the first option not only because it requires the least amount of effort, but also because it's the most natural, least invasive, and, given enough time, will almost always work. Fermentation is sometimes a stubborn wonder of nature, especially with high gravity beers or finicky yeast strains like Saison or Ringwood, and sometimes fermentation can take weeks longer than expected. Even under the perfect conditions, just remember, yeast is working on it's own schedule, so have a homebrew and some faith, and let the yeast do its thing.

    2. Rockabye Baby: Try giving the fermenter a really slow, "gentle rock". No splashing and no bubble making as you want to avoid oxidation. Hold one hand to steady the fermenter at the bottom of the bucket or carboy, and use the other hand to gently sway the beer back and forth a few times (not more than 5 or 6). The idea is to lovingly rouse the sweet little baby yeast from the bottom of the fermenter, giving them a gentle sway to coax them to get the job done.

    3. Some Like it Warm: In combination with the "Rockabye Baby" approach, consider raising your ferment temperature up a bit. Yeast tend to become more active at warmer (not hot) temperatures. Of course every beer has a certain flavor profile to shoot for, and that profile in very large part depends on your fermentation temperature and schedule, but if you've got a stuck ferment, then it's worth possibly taking it above that ideal range if it means getting your beer back on track. For example, if you're fermenting at 62 F, raise it to 68. To avoid off-flavors, be careful not to push the temp too much above that particular yeast's ideal fermentation temp because you might not appreciate the fusels or fruity esters lurking on the warm side of the Force.

    4. Call in the Reserves: You can pitch some additional healthy yeast to help finish the job. I'd stick with the same, or similar, type of yeast you started with, or use a more attenuative, clean yeast (a yeast that contributes no real additional aroma or flavor profile); consider, say, a California Ale yeast or an American Hefeweizen yeast before going with a super high-gravity Champagne-style yeast which can make your beer drier than Happy Hour at a Mosque. It wouldn't hurt to make a starter with the new yeast either. By the way, even though larger strains can metabolize longer starch chains like melibiose thereby further lowering the final gravity of a beer by a very small percentage, the attenuation limits of lager and ale strains do not differ in any significant way.

    5. Energize: Some brewers have had success kicking their fermentation back into gear by adding a small amount of yeast energizer to their stuck ferment. Most homebrew stores will sell the product which is usually a blend of diammonium phosphate, magnesium sulfate, yeast hulls and vitamin B complex. Luckily, I've never had to use yeast energizer, but it's an option to keep in your back pocket.

    6. Chemical Warfare: Some brewers use artificial enzymes to reactivate or increase the speed of fermentation in their beer. When time is money, I can understand the temptation, however whenever possible, try keeping your beer pure and natural and stay away from the Agent Orange.

    Well, there you have it. So the next time you're paid a visit by the ever-lurking shadow of the stuck fermentation monster, you’re now armed with a few more tricks to help you stare down one of the feared boogie men of brewing. Oh, by the way, when the nasty head of the stuck fermentation beast (in the form of a fussy little saison, naturally) reared its ugly head in front of Garret Oliver, brewmaster extraordinaire, and after he'd exhausted all the tricks in his book, he was tempted with the choice of adding an artificial, lab manufactured, yeast-steroid cure-all enzyme to the beer to get it going again. That choice was becoming more and more appealing as time went on and the pressure to produce mounted, but Garret stayed strong and sure enough after some time and additional yeast, the brew finished out and went on to win multiple awards. The moral of the story? Well, aside from keeping it real-ale, I guess it's the same moral from so many a brewing tale- RDWHAHB.

    Hope this would be helpful

    Tebuken
     
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  8. hreb

    hreb Pooh-Bah (1,748) Mar 4, 2005 Washington
    Pooh-Bah Society Trader

    Thanks for all the comments. I brew from extract with a grain mini-mash, in this case 7 lbs of LME + 3 lbs grain (malted wheat, pilsner malt). I pitched the starter on June 8 (1.067), by June 10 it was down to 1.026, and today (June 15) it is still 1.026, so there's 5 days of non-activity. I just gave it a few gentle swirls in the carboy, we'll see if that makes any difference.

    I use starter only out of an abundance of caution. I haven't tried to calculate pitching rate. Ambient temperature in the basement is about 65° F, so I don't think that's the problem, but I could try bringing it upstairs if nothing happens.
     
  9. reverseapachemaster

    reverseapachemaster Zealot (722) Sep 21, 2012 Texas

    How sweet does the beer taste? I am wondering if you are not getting good conversion in your mash and it is leaving behind a lot of unfermentable content in the beer.
     
  10. JohnSnowNW

    JohnSnowNW Initiate (0) Feb 6, 2013 Minnesota

    As has been mentioned, it is not recommended to make a starter with most dry yeast. Re-hydrate, yes...starter, no.

    The biggest benefit is that it is cheap and does not require a starter. In fact, with most dry yeasts, placing them in a starter would just deplete the reserves that the yeast manufacturer worked so hard to build into the yeast.

    http://www.mrmalty.com/pitching.php

    Whether that's what's causing your stalling issues, I cannot say.
     
  11. hreb

    hreb Pooh-Bah (1,748) Mar 4, 2005 Washington
    Pooh-Bah Society Trader

    I wouldn't say the beer tastes particularly sweet, but it is definitely not as dry as I'd like. There is definitely some residual sugar there. So, a little sweet? What kinds of unfermentable content could there be that would not only stay suspended in the beer, but still survive the boil, and also contribute multiple (0.008+) points of gravity? And how would I mash "better" to avoid that?

    Ok, no more starters for my dry yeasts. This was my first use of T-58, so for this one I bought a new packet, but sometimes in the past I've recaptured the yeast and pitched it in a future brew (I was really enjoying the results I was getting from US-05 for a while). Presumably I still need a starter when pitching re-claimed yeast...?
     
  12. VikeMan

    VikeMan Grand Pooh-Bah (3,043) Jul 12, 2009 Pennsylvania
    Pooh-Bah Society

    Either unfermentable dextrins, or fermentable sugars that the yeast didn't finish. Boiling doesn't get rid of either. Based on your question, I'd recommend reading www.howtobrew.com if you haven't already.
     
  13. hreb

    hreb Pooh-Bah (1,748) Mar 4, 2005 Washington
    Pooh-Bah Society Trader

    So I figured my beer was just final at 1.026. I measured a few times between 6/10 and 6/22 and each time confirmed that level. On 6/22 before heading out of town for the week I figured I'd rack it just to have a fighting chance at a reasonable level of haze / sediment come bottling time. So today (6/29) I came back to bottle and what do you know, gravity is now down to 1.021. I went ahead and bottled it -- hopefully it was really done this time. I wasn't around to check for airlock activity, so who knows, maybe my gravity readings were just thrown off by heavy non-fermentables suspended in the beer, and racking got rid of some of those, rather than facilitating further yeast activity. As long as the beer successfully bottle conditions without turning into an over-carbed mess I'll be happy.
     
  14. VikeMan

    VikeMan Grand Pooh-Bah (3,043) Jul 12, 2009 Pennsylvania
    Pooh-Bah Society

    With a rather weak attenuation so far, you went ahead and bottled after only one reading at 1.021. I wish you luck.
     
  15. kdb150

    kdb150 Initiate (0) Mar 8, 2012 Pennsylvania

    I'd be more worried about exploding bottles than the taste of over-carbed beer.
     
  16. hreb

    hreb Pooh-Bah (1,748) Mar 4, 2005 Washington
    Pooh-Bah Society Trader

    It's a gamble, but it's a risk I'm much happier to take at 1.021 than at 1.026. In my own experience the worst that's happened is I've had bottles that gushed foam right after opening -- never exploding glass. But there's a first time for everything.
     
  17. FATC1TY

    FATC1TY Pooh-Bah (2,502) Feb 12, 2012 Georgia
    Pooh-Bah

    Thats only 68 % and some change apparent attenuation.. Not quite super low, but it's very well on the low side of what I've read that people get for that strain.

    I would make sure your bottles are in a place where flying glass won't be an issue if it comes to that.
     
  18. ssam

    ssam Pundit (973) Dec 2, 2008 California

    This
     
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