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Dry Hop, Hop Creep, and D-Rest

Discussion in 'General Recipe Discussion' started by DazGore, 10/11/19.

 

  1. MHB

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    Posted 12/11/19
    Fair enough, Thomas Shellhammer is always worth reading, now anyone got the original paper? Its one I would like to read.
    Mark
     
  2. DazGore

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    Posted 12/11/19
    I tried to get it, but you have to be a member or something. That's on the Oregan State University website.
     
  3. MHB

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    Posted 12/11/19
    Me to, found it behind half a dozen paywalls. They want something like $30 USD to let me look at it, more to download...
    (GOM mode) I remember when the whole idea of the internet was to share knowledge for free... bastards
    Mark
     
  4. Nullnvoid

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    Posted 13/11/19
    Link? I wonder if I can access it through work
     
  5. goatchop41

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    Posted 13/11/19
    Ask, and ye shall receive
     
  6. goatchop41

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    Posted 13/11/19
    Google 'sci-hub' and thank me later
     
  7. MHB

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    Posted 13/11/19
    Too Soon?
    Thanks, will dive into the paper later but a quick scan it looks like it might answer a lot of questions.
    Cheers Mark
     
  8. Moog

    BIAB-ER

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    Posted 13/11/19
    did you mean this thesis paper?
     

    Attached Files:

  9. MHB

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    Posted 13/11/19
    Both good papers (at a quick glance), cant track down the one of the effects on beer FG caused by dry hopping (its the one behind the paywall) I think its this one: -
    K. R. Kirkpatrick, T. H. Shellhammer, “Evidence of Dextrin Hydrolyzing Enzymes in Cascade Hops (Humulus lupulus)” Journal of Agricultural and Food Chemistry 66, 9121−9126 (2018).

    Cheers Mark
     
  10. goatchop41

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    Posted 13/11/19
    Sci-hub delivers again
     
  11. MHB

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    Posted 13/11/19
    Excellent thanks.
    I tried searching Sci-hub for that paper but couldn't find it, have to spend some time learning how to use Sci-hub.
    Thanks again
    Mark
     
  12. goatchop41

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    Posted 13/11/19
    Perhaps it was the fact that the whole thing is written up in the form of a scientific paper, with clear attempts (although not overly successful) at following scientific method, that gave us that impression? It is quite obvious when reading the 'report' that they've tried to angle it in that way.
    The presentation of it clearly shows that it is intended to be seen as an attempt at scientific investigation/testing of the yeasts
     
  13. goatchop41

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    Posted 13/11/19
    No worries.
    Putting the whole reference (author, title, volume, etc.) in usually doesn't work for sci hub - a lot of the time you just need to put the title of the paper in.
    Failing that, google the paper and find the 'doi' for it (the doi is usually easy to find if googling it gives you a result in NCBI - the doi will be in the NCBI web page), then input the doi in to sci-hub. That is guaranteed to work
     
  14. wide eyed and legless

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    Posted 13/11/19
    Best place I have found for papers and books is this one.
    https://www.academia.edu/
    I downloaded Boulton & Quains book Brewing Yeast and Fermentation, for free normally would expect to pay $130 AU
     
  15. goatchop41

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    Posted 13/11/19
    That's a good one, cheers for that.
    Library Genesis is also great for textbooks and other books. In saying that, if I download a book and it is good stuff, I am then more than happy to go and pay for it through legitimate means. This way just lets me actually see the full content of the book and work out if it is right for me.
    Regarding the academic papers - academic journals are pretty scummy and make life hell for some researchers, so we shouldn't feel bad for getting those for free
     
    MHB likes this.
  16. TheWiggman

    Haters' gonna hate

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    Posted 15/11/19
    Sorry can't help but feel I need to address a few points here.
    Where is the general consensus to dry hop before fermentation was finished to address oxygen? I've dry hopped before and after, and the general consensus I've read is to dry hop after it's finished so that fermentation doesn't take some hop aroma with it. Though to be honest I've never been blown away with the impact of dry hopping.
    Re: sugars in the hops, I'm in line with Mark's thinking. As noted later the phenomenon of 'hop creep' isn't said to be due to the sugars in the hops.
    As for the timing and diacetyl rest... what I would have said's been said.

    All this has me wondering though - why are we talking about it? I've never heard to date anyone having an issue with dry hopping causing over-attenuation. Search back on this forum 15 years and nobody to my knowledge has opened a thread with "Dry hopped to buggery, exploding bottles / fizzy beer". There was one beer I recall where someone tipped about 1.5kg of hops into a 23l batch. I have this feeling that it's another botulism or HSA argument, that there are observable impacts from very high hop use at a clinical level but the net result for a home brew beer is SFA except in exceptional circumstances. I think I could do a lot more damage to a beer with poor technique than using too many hops (unless you don't like hops). In fact I'd argue don't use too many hops when dry hopping anyway because I've yet to be convinced that going hell-for-leather with dry hopping gets a good benefit for the dollars spent.
     
  17. DazGore

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    Posted 15/11/19
    @TheWiggman I am trying to find the source for the dry hop timing. I guess I am basing it on a lot of things I have read, both from brewers of well known American breweries and the general homebrewing public.
    A lot of it also stems from the hopping schedule of NEIPA's.
    It is based on the theory that when you open your fermenting vessel to add the hops you are letting in oxygen. If the wort is still fermenting a cushion of CO2 is protecting the beer somewhat (debatable), but any oxygen that does enter along with the hops, would be devoured by the still active yeasts.
    Yes, a lot of the dry hopping intention would still be stripped and carried away with the CO2, but some would still be obtained. And those that only whirlpool and not dry hop, their hopping is all subjected to the CO2 scrubbing affect.
    I have not experienced, to my knowledge, any of the so called hop creep, being higher alcol, extra fermentation, or higher volumes. But it seems to be a thing, seeing as a few breweries have noticed the impact and are taking precautions to avoid where and when they can.
    Myself, I don't care if my 5.5% APA becomes 6.5%, that's a bonus as far as I'm concerned. I keg, so the volumes is not really an issue.
    For me to add a couple of days to my beer after dry hopping to clean up any Diacetyl or secondary fermentation is not an issue.

    Daz
     
  18. goatchop41

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    Posted 15/11/19
    On a personal anecdote level, I think that the whole 'fermentation will blow off hop aroma' thing is bullshit, and is just some theoretical bollocks that gets repeatedly regurgitated without any substantiation.
    When I make a NEIPA/hazy beer nowadays, I pretty much only dry hop when I pitch the yeast. From my anecdotal experience, not only does this get me great, persistent haze, but the dry hop character is just as pronounced as it is when I do conventionally timed dry hopping, or even double dry hopping (one at pitching and one at the end of fermentation)
     
  19. DazGore

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    Posted 15/11/19
    Here is a .pdf of Oregon University's research on dry hopping, hop creep, sensory analysis of various hops, etc...
     
  20. wide eyed and legless

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    Posted 15/11/19
    I can't see there being that much sugar in hop flowers, the carbohydrates produced by the leaves will go into the root system for growth energy, and as they are wind pollinated they don't need nectar to attract bees. I would say the best access to any sugar reserves would be through the new shoots, probably why the Romans used to eat them.

    As I said earlier,once yeast are anaerobic respiration going around mopping up oxygen is not on the yeasts agenda.
     

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