Another stuck fermentation thread, sorry

Discussion in 'Homebrewing' started by Tebuken, Aug 1, 2016.

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  1. Tebuken

    Tebuken Initiate (0) Jun 6, 2009 Argentina

    Hey guys,

    So I have brewed 14 days ago 5 gals of IRA beer. It is the first time I have brewed using Wyeast 1084 that brought here(Argentina) from NYC . It is a pretty normal beer with OG=1050 mashed 150 F (1 hour). As it was a bit old yeast pack ( 19/04/2016) I have made a 1 lt 1030 starter using a stir-plate 3 days. I pitched a nice yeast slurry at 66 F and everything went normal, it gave me very high krausen that I used to top-crop a good qty. of new yeast. There was a hard fermentation when temperature reached 70 F and after 5 days there was no air-lock activity at all.So I thought it was done or near done, took a gravity read to find a surprise ...it was stuck, FG was 1020 but should be near 1011-12 .I let it go as it was , days have passed by and took another read to find the same number 1020.Now I am on the crossroads, I don´t know what to do, have almost 4 gals of another IRA beer brewed using Coopers dry yeast that had a stuck fermentation as well, I gently shook fermenter several times to rouse yeast, they have aroused indeed but beer has turned out staled. The point is I don´t want to add a different yeast strain to complete fermentation ,neither shake fermenter. I have collected new yeast of this strain, should I add this new yeast ?, is it possible I have a poor healthy yeast due the long travelling.?

    Any advice would be appreciated

    Greetings
     
    #1 Tebuken, Aug 1, 2016
  2. dmtaylor

    dmtaylor Savant (1,149) Dec 30, 2003 Wisconsin

    Hmm... I doubt it is a yeast health problem since you made a good starter several days in advance.

    It could be a recipe problem. What was your malt bill?

    Could be that your mash thermometer is not accurate and you actually mashed at 160 F instead of 150 F or something like that. Have you calibrated your thermometer with freezing or boiling water to see if it reads 32/212 F?

    How are you measuring the specific gravity? If you use a refractometer, it does not work properly in the presence of alcohol and correction factors need to be applied. If using a hydrometer, again, calibrate and ensure it reads 1.000 in plain water at about 60 F.

    If you are very confident and your fermentation truly is stuck at 1.020, you have two alternatives:

    1) Add a different yeast. I've gotten higher attenuation >80% from both Notty and US-05 lately, which is way higher attenuation compared to most other yeasts. I know this might sound crazy to some but you might want to make a yeast starter with one of those two dry yeasts and add that in. If you don't make a starter and just add the dry yeast in, it probably won't work very hard for you. You need to pitch when it is already vigorously fermenting in a starter for this to work. One pack of either one in a decent 1-1.5 liter starter (assuming 5 gallons beer) should do a nice job for you and fairly quickly.

    2) You can also try adding "yeast energizer". This has helped some of my fermentations in the past but is really just a last resort as I have no idea why it should even help at all. If your yeast is having a nutrient deficiency for some reason, this could help. But odds are slim this will help.

    I wish you the best of luck.
     
    #2 dmtaylor, Aug 1, 2016
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  3. Naugled

    Naugled Pooh-Bah (1,944) Sep 25, 2007 New York
    Pooh-Bah

    This may be a dumb question. but are you sure your hydrometer is working properly? I've had the paper with the markings printed on inside the glass tube slip on me once. Test it with water like dmtaylor suggests.
     
    #3 Naugled, Aug 1, 2016
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  4. Tebuken

    Tebuken Initiate (0) Jun 6, 2009 Argentina

    Thanks for your responses guys.

    Well , I have checked my hydrometers(2) as @dmtaylor suggested and found their both measurements are not accurate, the readings say 1004 using plain water at 60 F. I had 3 hydrometers, the older one(broken) was better quality than the new ones,it had litlle lead balls in the glass tip, the new ones have some molten metal not very nice at all.The point is I am a bit bewildered at the moment, because a brand new ATC refractometer that reads the sample of this beer at room temp. shows 8 Brix. I use Beersmith Software refractometer tool introducing OG1050 and FG 8 brixs to receive a corrected FG to 1020(that´s why I didn´t suspect there was a problem with the hydrometers). Refractometer it is calibrated by the producer( I have checked it as well using plain water at 68 F) , but it should read some number in Brixs that should result in a 1016 FG. Am I wrong?
     
    #4 Tebuken, Aug 1, 2016
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  5. dmtaylor

    dmtaylor Savant (1,149) Dec 30, 2003 Wisconsin

    Sean Terrill's calculator with initial Brix of 12.8 and final of 8.0 with correction factor (this is necessary!) of 1.04 gives an actual final gravity of 1.017, which is right in line with the 1.016 that your hydrometers expected. And furthermore, your apparent attenuation is 66% which is indeed low for this yeast strain. So, it might still help to add more yeast.

    http://seanterrill.com/2012/01/06/refractometer-calculator/
     
    #5 dmtaylor, Aug 1, 2016
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  6. Tebuken

    Tebuken Initiate (0) Jun 6, 2009 Argentina


    Do you think it could be useful to add this recently top-cropped yeast?
     
    #6 Tebuken, Aug 1, 2016
  7. dmtaylor

    dmtaylor Savant (1,149) Dec 30, 2003 Wisconsin

    Only if the yeast is currently munching on something. If they've already fallen asleep in your refrigerator, it won't help as much. They need to be vigorously fermenting something in order to work.
     
    #7 dmtaylor, Aug 1, 2016
  8. Tebuken

    Tebuken Initiate (0) Jun 6, 2009 Argentina

    They fell asleep 14 days ago, maybe I can make a new starter?
     
    #8 Tebuken, Aug 1, 2016
  9. dmtaylor

    dmtaylor Savant (1,149) Dec 30, 2003 Wisconsin

    Yes, make a starter, that would be as good as it can get. Or try a more attenuative yeast strain. Or both.
     
    #9 dmtaylor, Aug 1, 2016
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