The science behind beer degradation

Discussion in 'Beer Talk' started by Snowcrash000, Feb 10, 2020.

  1. Snowcrash000

    Snowcrash000 Poo-Bah (2,252) Oct 4, 2017 Germany
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    Could anyone point me towards some scientific studies and articles that explain the process of hop fade and other factors contributing to beer, especially hop-forward beer, degrading over time? I've been told by breweries here in Germany that their IPAs are fine for up to 12 months, that they feel justified setting 18 months best-by dates for their hoppy beers, that higher ABV means longer durability and that craft beer, in general, only gets better with time, like wine. I also vividly remember a brewer from a famous Cologne Kölsch brewery telling me that cans are terrible vessels for beer because they make it taste bad. It's incredibly how stuck in the past people can be around here.

    I don't know if these people actually believe that or if they are only saying it for PR reasons, but I'd really like to be able to hit them with some cold, hard facts about the importance of freshness with hoppy beer when arguing with them and link them some scientific studies as proof. It may seem rather sad that this is necessary when talking to breweries and brewmasters who should know better, but this just seems to be where we are here in Germany, where 12 month best-by date for industrial macro beers have been pretty much ingrained into the German consciousness over decades.
     
  2. herrburgess

    herrburgess Meyvn (1,121) Nov 4, 2009 South Carolina
    Industry

    can you maybe post some pics of beers you've bought/consumed/seen on shelves recently with the best-by/bottled-on dates for reference?
     
  3. jesskidden

    jesskidden Poo-Bah (1,944) Aug 10, 2005 New Jersey
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    Here's a start - do some more Googlin' of "Dalgliesh" with various other terms added... Not sure if I ever found the original 1977 report (see footnote).
    [​IMG]
    Note that the (US) Brewers Association has an image of the above graph titled "Schema of beer aging/flavor changes" with "months" added along the X axis (months 1- 6) which might turn up in Google Image searches - not sure if Dalgliesh would agree.
    So, they consider that their beers are "fine" for 12 months, but the brewers are good with adding 6 month additional shelf life so buyers can purchase "less than fine" beer?:rolling_eyes:

    Lots of US brewers in the post-Repeal/pre-Craft era had pull-dates based on shelf life lengths of 2 - 4 months See BEER FRESHNESS AND DATE CODING
     
    #3 jesskidden, Feb 10, 2020
    Last edited: Feb 10, 2020
  4. Snowcrash000

    Snowcrash000 Poo-Bah (2,252) Oct 4, 2017 Germany
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    To what end? Best-by dates are completely arbitrary in Germany because they can be set for anywhere between 6 to 18 months or even longer, with 9 months being the norm for the smaller craft breweries and 12 months for the large industrial breweries, and bottled-on dates DO NOT EXIST here except for incredibly rare exceptions.

    I've written to about 20 craft-focused breweries in Germany recently and so far 17 of them have gotten back to me, citing best-by dates of 6-22 months for their IPAs, with 9 months being the most common. Interestingly enough, there's a clear pattern of the newer, younger breweries using much shorter best-by dates than the craft subdivisions of long-standing traditional breweries. Also, the vast majority of breweries have said that they are not planning on introducing filling dates.

    My favorite was one brewery telling me they set 22 months for their Black IPA because it's a dark style and another that craft beer, like wine, only changes for the better with age.
     
  5. Snowcrash000

    Snowcrash000 Poo-Bah (2,252) Oct 4, 2017 Germany
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    To be fair, those were two separate comments from different breweries, but they are no less ridiculous on their own.

    Thanks for the graph, but what is "ribes" supposed to refer to? I also noticed that there is a line for hop bitterness but not for hop aromatics, which is a bit of a shame.
     
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  6. herrburgess

    herrburgess Meyvn (1,121) Nov 4, 2009 South Carolina
    Industry

    I honestly would like to see, say, a Malzmuhle Koelsch bottle with dating bc I failed to pay attention to that when I was over there and missed it.

    As to darker beers having a longer shelf life, id tend to generally agree as the roasted (or in the case of a beer we brew, smoked) malts can have anti-oxidative properties.

    this is another reason id like to see a variety of beers that you mention. some are more subject to quicker degradation than others for a number of reasons: vessel; style/malt used; hop and other desired aromas; the equipment and processes used (low DO brewing methods, filtration, pasteurization, etc).
     
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  7. jesskidden

    jesskidden Poo-Bah (1,944) Aug 10, 2005 New Jersey
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    Well, I posted the graph not so much as an "answer" to your question but because "C.E. Dalgliesh" (best known for the illustration, unfortunately, rather than the paper where it originated) is a good starting point for your research into the subject. Lots of the work in the +40 years after Dalgliesh cite or were continuations of his original work.

    For "Ribes" see The development of ribes flavour in beer is closely correlated with headspace air.
    "Blackcurrent" is the common answer - which, for many (including me) isn't much help at all...:astonished: Seen it referred to as synonymous to "catty", too (although I've also seen lightstruck flavor called "catty" - incorrectly - thus confusing it was "skunky")... Check out the various BEER FLAVOR WHEELS on the 'net .
     
    #7 jesskidden, Feb 10, 2020
    Last edited: Feb 10, 2020
  8. FBarber

    FBarber Poo-Bah (2,801) Mar 5, 2016 Illinois
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    I think @JackHorzempa has one that he references occasionally on here (or maybe that one is the one about cold storage?)
     
  9. herrburgess

    herrburgess Meyvn (1,121) Nov 4, 2009 South Carolina
    Industry

    as a corollary to the dark malts point; pale malts can produce more precursors to off flavors (that emerge with varying degrees of age) such as diacetyl or pentanedione. gotta consider the color of the glass the beer might be packaged in, too, in terms of what might happen. not to mention the packaging methods (big places tend to have much better practices than smaller places when it comes to oxygen ingress during/throughout packaging). I am familiar with the various charts, but only persoanlly use them as a general guideline and not as fully descriptive (much less PREscriptive) for every type of beer (that we brew, or otherwise...just too many variables out there)
     
    #9 herrburgess, Feb 10, 2020
    Last edited: Feb 10, 2020
  10. herrburgess

    herrburgess Meyvn (1,121) Nov 4, 2009 South Carolina
    Industry

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  11. jesskidden

    jesskidden Poo-Bah (1,944) Aug 10, 2005 New Jersey
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    Well, the BA is free to download - somewhere I found the Food Chemistry article for free as well since I've got the pdf in my files - unfortunately, I guess I just hit "SAVE" and don't normally save the link to the original source - but, yeah, sometimes they do disappear.

    (But, that's what Google's for... :wink: much more comfortable to sit at home rather than work in some stuffy, florescent-lit library, trying to read microfilm [I get motion sick from them damn things] or microfiche copies and paying 10¢ per page for lousy repros...)
     
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  12. herrburgess

    herrburgess Meyvn (1,121) Nov 4, 2009 South Carolina
    Industry

    anyone know if it's the case that hop extract degrades (or even skunks) slower than hop pellets/flowers/cones? gap in my knowledge...
     
  13. jesskidden

    jesskidden Poo-Bah (1,944) Aug 10, 2005 New Jersey
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    The products themselves or the beer brewed with them? Pretty sure the hop extract manufacturers suggest they are good for years:
    (Of course, it was common 75 years ago for hop dealers to still be selling the previous years' harvested dried/baled hops).

    Have never seen anyone claim the use of extract instead of whole or pellets extends the shelf of life of the beer itself (but, then, examples of brewers admitting to using extract had been very rare up until recently). I have an interview with a Schlitz brewmaster claiming they used extract because of its longer shelf life "...natural hops can spoil when traveling or get stale but extract is taken when the hops are all fresh and doesn't spoil easily".

    And, of course, re: "skunking" - there are the so-called "light-stable" hop extracts, like Barth-Haas' Redihop:
    .
     
    #14 jesskidden, Feb 10, 2020
    Last edited: Feb 10, 2020
  14. herrburgess

    herrburgess Meyvn (1,121) Nov 4, 2009 South Carolina
    Industry

    yeah...didn't mean to imply beers as a whole would hold up longer, but maybe hop character? it's a fairly major ""scandal" in germany that the big places use hop extract. I suspect some may use the ones that protect against skunking but I'm not certain.
     
  15. jesskidden

    jesskidden Poo-Bah (1,944) Aug 10, 2005 New Jersey
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    Yeah, I think there are a lot "beliefs" in that area, but I've never seen anything concrete. It's sorta like the current trope that "Cans keep beer fresher than bottles" - yet have never seen a brewer have different shelf life for cans vs bottles...

    Yeah, I'd say the US macro industry went through the same thing in the 1980s but they now freely admit it.
    (Check out PABST's circa 1970s brewing diagram for one example).
    Now, many the "craft" brewers seem to still be reluctant to say it...

    I'd don't know - IF you're using extract, why not use the "light stable" stuff? Seems nuts. I'd guess Corona and Modelo Especial would be examples?

    I was surprised recently when I was researching that new Bitburger/Sierra Nevada beer,Triple Hop'd Lager, to read the keg (but not the can) label and see "Hop Extract":

    [​IMG]
     
  16. zid

    zid Meyvn (1,411) Feb 15, 2010 New York
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    I'll get flamed for this. I applaud you if your efforts actually make a difference, but all of the science in the world can't turn something subjective into something objective. We're not talking about the rate of salmon spoiling. The dates on beer are a business decision. If the brewer feels that their product is still fine at 6 months or 24 months, that's up to them. If their dating policies cause many customers to be unsatisfied, then the brewer will face the business repercussions. If marketplace realities dictate that brewers use a longer shelf life than they'd ideally want for their product, then that's something that they've decided to live with as businesspeople. You can do what you want as the purchaser.
     
  17. Snowcrash000

    Snowcrash000 Poo-Bah (2,252) Oct 4, 2017 Germany
    Moderator Society Trader

    Well, I didn't necessarily write to them "to make a difference", although that would certainly be a nice side effect, but mainly because I want to be able to tell how fresh the beer by these breweries is before buying it.

    I decided not too long ago that I would like to buy more German craft beer, which I've always shied away from in the past due to the lack of filling dates and thought that if I could just find out the lengths of the best-by dates this wouldn't be a problem anymore.

    Of course this doesn't make the beer on the shelves any fresher, but at least I will be able to pinpoint if and how much beer is actually available fresh and make my purchasing decisions accordingly.
     
  18. hopfenunmaltz

    hopfenunmaltz Meyvn (1,485) Jun 8, 2005 Michigan

    YCH says they last for years, but those are often for bittering.

    Some varietals extracts are being made, but I don't know how well the aroma holds up.
     
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  19. jesskidden

    jesskidden Poo-Bah (1,944) Aug 10, 2005 New Jersey
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    Yeah, but I was surprised by the OP's comments about not just the length but the variety of different lengths of recommended shelf life periods and the fact that so few note a bottling date. So, if he, like most of us, use our own cut-off period for buying beer, it ain't so easy if you don't know what that "BEST BEFORE" date is based on.

    Seems to me here in the US it is mostly German beers that commonly have both dates, exactly 1 year apart - so you think to yourself, "Oh, thanks for not making me do the math on that one..." :rolling_eyes: .

    I didn't, did I :grin:. Hey, 'cause I basically agree with you. I've been bitching about no dates, confusing dates, illegible dates, unknown code methods, for longer than some folks here have been drinking beer but lately I do think, after reading yet another post ranting about missing/hard to read/old date codes, "Yeah, well, just buy something else...".

     
    #20 jesskidden, Feb 10, 2020
    Last edited: Feb 10, 2020
  20. Snowcrash000

    Snowcrash000 Poo-Bah (2,252) Oct 4, 2017 Germany
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    I found it here, but unfortunately it seems to be more about off-flavors and oxidation than fading hop aromatics.

    http://depa.fquim.unam.mx/amyd/archivero/ARTICULOGRUPO8_25527.pdf

    I also found these two articles, which I haven't read in their entirety yet though.

    https://www.realbeer.com/hops/aroma.html

    https://web.archive.org/web/20131028184350/http://captainsbeerblog.com/2010/03/23/fading-hops/
     
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  21. AZBeerDude72

    AZBeerDude72 Poo-Bah (1,877) Jun 10, 2016 Arizona
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    OP honestly its not worth your time. Its obvious they are never going to change their way of thinking. Any beer drinker knows how age impacts certain styles of beer especially very hop forward beers. If a brewery is going to deny this and state otherwise then why expend a moment on them, they won't listen.

    I equate this to the coffee industry. They sit and sell crap that is old and call it fresh. Anyone who knows coffee knows the real shelf life but we see cans/bags over a year old on shelves and they consider it fresh. This example is sort of the same thing.

    Cheers
     
  22. jesskidden

    jesskidden Poo-Bah (1,944) Aug 10, 2005 New Jersey
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    I don't know - it is a LOT easier to find and/or understand the date codes on US beers (and many imports) today than it was 20 or 30 years ago. I'd say that some of that is based on consumer demand/complaints.
     
  23. Snowcrash000

    Snowcrash000 Poo-Bah (2,252) Oct 4, 2017 Germany
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    Malzmühle is actually a bit of an exception in the Kölsch landscape as they are one of the very few breweries that still brew "in-house" and also set a 6 month best-by date instead of the more common 12 month best by date for Kölsch.

    Asking them about their best-by date at the brewery still was quite an unreal experience though, which I recounted in this thread here, which you may find interesting.

    https://www.beeradvocate.com/community/threads/frueh-koelsch-bottle-date.610449/

    I'll try to snap a picture of a Mühlen bottle at the next opportunity I get.
     
  24. AZBeerDude72

    AZBeerDude72 Poo-Bah (1,877) Jun 10, 2016 Arizona
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    True, I think a lot of the change here had to do with consumers wanting the info. I think the beer culture here is a lot different though. I guess the big question is are consumers as interested elsewhere? The breweries there would change if people demanded it and it impacted sales etc. Any Ba folk from that part of the world who can give us some views into the local scene and if there is a movement for things like this?
     
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  25. herrburgess

    herrburgess Meyvn (1,121) Nov 4, 2009 South Carolina
    Industry

    agree with the folks that it's too nebulous to pin down. hell, the brewer of heady topper says his beer tastes best (to him) at 9 (?) weeks when the geeks will insist it's ruined by then
     
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  26. herrburgess

    herrburgess Meyvn (1,121) Nov 4, 2009 South Carolina
    Industry

    asking the koebes for freshness dates on the bottles sounds like something from koelner legend. can only imagine their reactions and (rehearsed) surliness. ha!

    I disagree that them (and others) not knowing offhand meant no one much cares about freshness there. to me it would seem that people buying from the source simply *expect* freshness...and, as the brewer points out, almoat always receive it
     
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  27. AZBeerDude72

    AZBeerDude72 Poo-Bah (1,877) Jun 10, 2016 Arizona
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    Na, its got 3 more weeks on it if you use the old 90 rule for IPA. Even then its probably fine but will it be as intended, I guess not but I am sure its still tasty. I always leave it up to the consumer, in the end they know how flavors change for each style they drink.
     
  28. zid

    zid Meyvn (1,411) Feb 15, 2010 New York
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    I'm sorry if I'm misunderstanding you completely @Snowcrash000
    I thought your first post was indicating that you've already figured out the shelf life dates set by the brewers from asking them directly and now you want scientific evidence to show them the importance of setting more appropriate best-by dates. I'm confused.
     
  29. Snowcrash000

    Snowcrash000 Poo-Bah (2,252) Oct 4, 2017 Germany
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    Finding out about the best-by dates was the original intent. A few of them have been so insufferably self-important in their replies though that yes, I'd like to set them straight a little. I'm mainly interested in whether they actually believe this stuff themselves or if it's just PR talk.
     
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  30. JackHorzempa

    JackHorzempa Poo-Bah (4,368) Dec 15, 2005 Pennsylvania
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    I think this is the graph you are thinking about:

    [​IMG]

    The above is from Dr. Charlie Bamforth and is predicated upon the Arrhennius Equation. As can be easily discerned, beer at room temperature will show signs of staling at around 100 days; this is consistent with AB's best by duration for a beer like Budweiser (which is 110 days).

    How long a beer will still be good is also a function of beer style. For example, Stone Brewing states that for their hoppy beers (e.g., Stone IPA) they are best consumed within 90 days of packaging.

    Cheers!
     
  31. zid

    zid Meyvn (1,411) Feb 15, 2010 New York
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    It's probably unlikely that a brewer will tell you that they do not believe the dates they are putting on their product. Does a politician say that he's lied? But fortunately, it doesn't ultimately matter much anyway, because what matters more is confidently knowing your personal preferences outside of the external noise of conventional wisdom, brewers, BeerAdvocate, best-by date codes, graphs, etc. (despite the value of those things).
     
  32. Ranbot

    Ranbot Savant (907) Nov 27, 2006 Pennsylvania
    Society

    @Snowcrash000 You might find some useful information in this old [closed] discussion too: https://www.beeradvocate.com/community/threads/old-ipas.177842/
    By page 2 brewers like Starkbier (Victory), Bulletrain76 (Firestone Walker), Peter_Wolfe (AB-InBev), and a few others jump with a lot of technical details on staling, packaging, storage, etc.

    I bet @Peter_Wolfe knows something about that subject.
     
  33. Snowcrash000

    Snowcrash000 Poo-Bah (2,252) Oct 4, 2017 Germany
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    I actually had a rather nice conversation with the brewmaster over the phone today where he agreed that the best-by dates were too long and basically admitted that his hands are tied by distributors and retailers who insist on them, which is a story I've heard many times before.
     
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  34. Snowcrash000

    Snowcrash000 Poo-Bah (2,252) Oct 4, 2017 Germany
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    @herrburgess here's a picture of a Mühlen Kölsch bottle with the best-by date.

    [​IMG]
     
  35. Immortale25

    Immortale25 Poo-Bah (3,321) May 13, 2011 North Carolina
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    I just wanna say I miss your old Tom Waits avatar:slight_frown:
     
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  36. Snowcrash000

    Snowcrash000 Poo-Bah (2,252) Oct 4, 2017 Germany
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    Haha, yeah, me too sometimes. Change is good though :grin:.
     
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  37. Immortale25

    Immortale25 Poo-Bah (3,321) May 13, 2011 North Carolina
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    This leaves me scratching my head because I view Germany as the land of unpasteurized wheat beers and I doubt any brewer would let those go for that long. Do you think they're still operating under the "Hops are a preservative, that's how the IPAs made it from England to India back in the day" misconception (for lack of a better term)?
     
  38. Snowcrash000

    Snowcrash000 Poo-Bah (2,252) Oct 4, 2017 Germany
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    No, they are basically being forced to set their best-by dates for that long by distributors and retailers. That's just the way it is in Germany, even Stone Berlin IPAs used to carry a 9 month best-by date here, now up to 12 months since BrewDog took over their facility.
     
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  39. unlikelyspiderperson

    unlikelyspiderperson Meyvn (1,167) Mar 12, 2013 California
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    Are there any craft centric stores or distributors starting up in Germany? Or are distributing brewers basically beholden to the large retailers/ distributors and their demands?
     
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