Yeast attenuation oscillations

Discussion in 'General Brewing Discussions' started by Gledison, Oct 12, 2017.

  1. Gledison

    Gledison Active Member

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    Hey everyone,
    As i was following the measurements of SG using @Nosybear spreadsheet i thought i had something wrong. I´m getting a much lower gravity than predicted. After measuring with a Hydrometer, it seems that my attenuation was 91%. The prediction was 72%. Im using a Nothingham Danstar Ale dry yeast.
    How do you guys deal with These differences in attenuation (predicted x measured) ? just want to avoid having extra 2% buzz in a low Body beer.
    cheers
     
  2. J A

    J A Well-Known Member

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    Difference between attenuation predicted by calculator and actual attenuation is common. The percentage attributed to yeast in the pull-down menu on the calculator is an average (and BTW, Notty seems to be 77%). Since I haven't looked into the spreadsheet, I don't know where you got your 72% attenuation prediction.
    Nottingham is notorious for high attenuation. Well over 72% isn't surprising, though I've never gotten over low 80s with it. Attenuation is affected by mash parameters and other things so it may vary batch to batch. When choosing a yeast in the calculator, use the custom attenuation box when your experience has shown an attenuation that's different from the average.
    In order to calculate and predict accurately, do some research to get a sense of real-world attenuation that other brewers get from a particular yeast. Also, make sure that your recipe includes accurate mash times and temps in the Mash Guidelines section. Final attenuation in the calculator is determined by that and if your recipe says one thing and you're doing something else, there can be some difference between predicted and actual attenuation.
     
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  3. Nosybear

    Nosybear Well-Known Member

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    I just did get into the low '80s with Nottingham. And I'm not really happy with the result, either, very harsh and unless I'm completely off, phenolic. My calculator is a quick and dirty implementation of the formulas in Zymurgy a few months ago - they seem to work for me but I wouldn't count on them working for everyone. Wort correction factors vary between refractometers. Mine's off by about 0.3 points for wine: I read 25 Brix, professional equipment at the University of Colorado Research Station reads 24.7.
     
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  4. J A

    J A Well-Known Member

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    I used it for a couple of batches...low-gravity Blonde and a double batch of session-strength Pale Ale pitched on the cake. I found it to be less than clean, also, and with a harsh edge like you mention. It's aged fairly well, but it's not the quick-turnaround choice I thought it'd be. I think it'd be better for the darker bitters, milds, brown ales and stouts more common to English brewing. For something fairly light and crisp, it's a little edgy. That being said, I opened a bottle that a fellow brewer had left in my fridge about 6 months ago that was a Maris Otter/ EKG smash using Notty and it was superb. I remember having that beer early on and it was quite fine, but not nearly this good. Very clean and super crisp. ;)
     
  5. Nosybear

    Nosybear Well-Known Member

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    So there's hope for my Frankenbrew.... :)
     
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  6. The Green Man

    The Green Man Active Member

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    I have used notty with my last 3 brews. Got some packets very cheap and heard that it was popular, but I'll not be using it again for a while. Same reasons as you all mention, very high attenuation and this kind of harsh edge. I thought it was me, or my newbie brewing, but maybe not. With my small batches my brews aren't going to get anywhere near 6 months conditioning. I'm using S04 now and with the next brew and then the world is my yeasty oyster.
     
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  7. Gledison

    Gledison Active Member

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    #7 Gledison, Oct 13, 2017
    Last edited: Oct 13, 2017
    my first brew was from a all grain kit. It came with Notty (im being cool now :p) and the result was quite ok.Therefore i startet to get that yeast for my first brews. I´ve tested the S05 as well and it was quite similar (for IPA and session Ale).
    What do you guys mean with "harsh edge" ? Is out there an overview about yeasts regarding flavors x attenuation? (edit: just found some info) faster the yeast = worse? (high phenols, or other side products). Im talking here using different yeasts but keeping the same conditions.
    cheers
     
  8. J A

    J A Well-Known Member

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    I'd say as a rule, no, that wouldn't be the deciding factor. And degree of attenuation wouldn't either. by itself. S-04 can finish out extremely quickly but is a smoother-feeling yeast, IMO. It can leave a little yeasty bitterness that takes a bit to age out, but it's not the same. S-33 is an animal, finishing out some beers in 24 hours, but it leaves a very smoothe feel and flavor...it also doesn't attenuate as far, though.
    High attenuation isn't what I attribute the harshness to, either, though it definitely has something to do with it. I've had session beers with US-05 go to the same attenuation as what I've gotten with Notty, but the flavor and feel is very different - very crisp and dry but not as harsh or edgy.
    I think Nottingham has its place. I'll use it next time I do a big, malty oatmeal stout, for instance. I could see it working very well to give some dry malt complexity and crispness to offset the residual sweetness and softer mouthfeel of a beer like that. For Ordinary Bitters and such, I'll stick with S-04 since I've had really good luck with that.
     
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  9. Gledison

    Gledison Active Member

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    yeah, it makes sense.
    Im just finishing my IPA and I hope for some extra miracle that it doesn't come with no body. Alcohol content is a way higher than I wanted and if its too dry, will be horrible.lets see.
    cheers
     
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  10. J A

    J A Well-Known Member

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    Dry, crisp IPAs are fine. If you haven't gone overboard with harshly bitter hops, you needn't worry. Lots of late additions in IPAs tend to accentuate the body and sweeter flavors, especially if you've used any "juicy" hops in the late/dry-hopping.
     
  11. Gledison

    Gledison Active Member

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    Maybe im lucky. Thats exactly what ive done. Late addition + Whirlpool and niw fi.ishing a dry hopping by cold crashing. Lets See;)
     
  12. The Green Man

    The Green Man Active Member

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    Just bottled my latest brew. Rehydrated S04 looks like its attenuated to 82%. Not what I was expecting. Not sure if I'm happy or not...I was gunning for sweet malty brew, mashed high and didn't add any sugar. The abv is 4.9ish which is fine but will I get the sweet, malty goodness? Will taste the sample later.
     
  13. J A

    J A Well-Known Member

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    Depending on malt selection, S-04 has given me bready malt notes or fruity-sweet malt notes. It's unusual to get that sort of attenuation so you probably won't have a lot of residual sweetness, but if you've used a fair amount of Maris Otter, Munich, Vienna in the base malt or a relatively high percentage of lighter Crystal malts, there'll be some sweet maltiness for you.
     
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  14. The Green Man

    The Green Man Active Member

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    #14 The Green Man, Oct 15, 2017
    Last edited: Oct 15, 2017
    [QUOTE="J A, post: 43382, member: if you've used a fair amount of Maris Otter, Munich, Vienna in the base malt or a relatively high percentage of lighter Crystal malts, there'll be some sweet maltiness for you.[/QUOTE]

    Grain bill was 45% MO, 35% German Pale Ale, 10% Crystal 60L, 5% Caramber and 5% whealt malt (for mouthfeel and head retention). Enough for any residual malty sweetness? Bit of fruit would be nice. Not sure why I got the high attenuation. Used the yeast calculator (Pro 75 setting), so didn't over pitch. But, that was 9g for a 9litre (nearly 2 gallon) batch...which does seem a lot.
     
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  15. Gledison

    Gledison Active Member

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    Ler me know how it tastes.
    I will plano for the future having some of the base malta with higher amount of unfermentable sugars to keep balance..
     
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  16. J A

    J A Well-Known Member

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    That sounds great! I can't imagine that it will be thin or too dry.
     
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  17. Gledison

    Gledison Active Member

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    If Cara Cristal 10, for example, add mostly unfermentable sugars, I don't understand why when added to the ABV calculation it shows similar ABV to a Pale Malt or pilsner. IF such malts have high unfermentable sugars why does it counts for ABV? I understand that for the original gravity It will show all dissolved sugars in the wort, but in the calculation formulas its not included only the fermentable % of each malt?
     
  18. J A

    J A Well-Known Member

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    I don't think they add mostly unfermentable sugars, but there'll be more from those malts than base malts. Pale ale malt shows 37 PPG and Carapils, for instance shows 33 PPG. The same amount of Carapils will give lower OG and lower ABV. When there's a lot of dextrine in the malt - Crystal, etc - mouthfeel is mostly affected but I find that there's some flavor that registers as sweetness.
    I'm not really sure what really happens to the enzymatic action during the process of making Crystal malts, but if I understand correctly, not all the starch is converted. There's still some starch to be converted through the action of the enzyme in the base malt and that will be more fermentable, depending on mash temp.
    It would be interesting to do some SMASH batches of base malts and Crystals and find the specific differences in the real world.
     
  19. Gledison

    Gledison Active Member

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    I agree. its crazy how all the possible combinations lead to completely different results. I read that Carapils have no or little diastatic power which need to be provided by the base malts in order to be able to break down the starches.
    We use the ppg in order to calculate the OG but this will give us just the dissolved surgars right? or the ppg is a number for only fermentables.? if so, lactose has a ppg of 35 and we know that is almost mostly not fermentable. I think that only by having the certificate of analysis of each grain one could be more accurate :p. however would be great to have the calculators taken into account that certain % of the ppg wont count for the ABV..
     
  20. J A

    J A Well-Known Member

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    I'm seeing 41 PPG for Lactose and 0 ABV contribution, so it seems to be taking into account the lack of fermentability.
    The calculator seems to do a pretty good job of tracking what will happen to the ingredients during mash and fermentation, but, yeah, the real-world results are sometimes more than the sum of the parts, either in a good way or bad. ;)
     

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