How much does keeping a beer cold really help retain hop aroma?

Discussion in 'Cellaring / Aging Beer' started by draheim, Mar 19, 2012.

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  1. draheim

    draheim Poo-Bah (2,461) Sep 18, 2010 Washington

    Thinking specifically about super-aromatic beers here, it seems like hop aroma falls off really quickly, no matter what you do. Examples include Surly Abrasive, Lagunitas Sucks, Pliny... after just 2 or 3 weeks I noticed a surprising decline in that "blast of fresh hops" on the pour. Do certain hop varieties fare better/worse in this regard? If I hadn't refrigerated them (just kept them in the cellar @ 52 degrees) would this have gone even faster? Or do the aromatics in hops just have an internal half-life that keeps ticking no matter what?

    I think I notice this a lot more in the aroma than in the taste, but since these two senses are intertwined to some degree this might be hard to distinguish concretely.

  2. Luv2Brew422

    Luv2Brew422 Initiate (0) Jan 7, 2012 California

    I have noticed that beers with whole cone hops will stand the test of time a while longer than beers brewed with hop pellets and hop extracts. Keeping the beers at a colder temp will help the hop profile last a little (but not much) longer as well due to oxygen not taking as much of an effect on the beer at cooler temp vs warmer temp.
  3. JackHorzempa

    JackHorzempa Poo-Bah (4,176) Dec 15, 2005 Pennsylvania

    Refrigerating your hoppy beers will definitely ‘help’ in mitigating the fading of hop aroma. I am uncertain whether this could accurately be quantified.

    As regards your more general question of: Do the aromatics in hops just have an internal half-life that keeps ticking no matter what? The short answer is that hops will indeed fade over time no matter what. You can certainly extend the life of hoppy beers through refrigeration but the hops will eventually fade no matter what.

    Some interesting discussion on hop fading:

    “Tom Nielsen, Sierra Nevada’s senior research analyst focused on hop degradation, says that their research has shown that after about two and a half to three months, hop aroma in a packaged beer, derived mainly from beta acids in the hop flower, has already started to diminish significantly. It’s a sentiment backed by Patrick Langlois at Great Divide in Denver, brewers of notable hoppy beers including their Fresh Hop Pale Ale, Titan IPA, and Hercules Double IPA. “Hops tend to dissipate in three to four months, which is why that is the recommended shelf life for most of our beers.”

    According to Nielsen, agitation during shipping can be a significant contributing factor to degradation in aroma. As a beer sits on delivery trucks and eventually finds its way to your local liquor store, the beer’s aromas can be kicked up through the head space and slowly forced out of the crown liner, a process Sierra Nevada refers to as scalping. Nielsen also says oxygen will destroy hop aroma very quickly, whether naturally over time, or through the bottling process.

    “We’ve found the hop aroma of a fresh beer shipped overnight from Boston compared to the same beer that just sat here in Chico was very much reduced,” said Nielsen. “This degradation doesn’t noticeably impact bitterness. But since aroma plays a significant role in your perception of taste, it can greatly influence your overall enjoyment of the beer.”

    Gerri Kustelski, director of quality assurance at Summit Brewing in St. Paul, agrees.

    “Organoleptically, there may well be discernable changes,” Kustelski said. “Bitterness can be masked by oxidation and aging, and aroma even more so. You begin to slowly loose the aroma imparted by dry hopping fairly quickly, possibly within several weeks. Packaging and distribution processes including shipping and temperature control can affect the flavor stability of beer and, thus, affect the perception of hop aromas and bitterness.”

    The relative levels of alpha and beta acid compounds in a packaged beer also lends perspective to how sensitive and fragile hops can be.

    “Aroma compounds are typically measured in parts per billion, compared to bittering compounds which are evaluated in parts per million,” Nielsen said. “If you lose half of your aroma compounds through agitation in shipping, that’s a much more dramatic degradation compared to bitterness. When you’re talking about aging a beer for many years, like our BigFoot Barleywine, the bitterness will eventually fade and change character, but generally speaking aroma is the first component to quickly fall out.”
    Pahn, KAF and drtth like this.
  4. draheim

    draheim Poo-Bah (2,461) Sep 18, 2010 Washington

    All really interesting info, thanks for putting that together.

    As to the selected quote above, I suppose one way to "quantify" this would be to buy a 6-pack of the same beer and put three in the fridge, keep three @ room temperature, and do side/side comparisons over a period of several weeks/months. I'm wondering if anyone has already done this. If not, maybe I'll give it a try.
  5. JackHorzempa

    JackHorzempa Poo-Bah (4,176) Dec 15, 2005 Pennsylvania

    If you are willing to run the experiment please do and report back.

    Just some words of ‘caution’ in that it would be very difficult to generalize your experiences since there are so many variables. The types of ‘results’ you get will likely really vary based upon the particular beer (I would guess that Pliny the Elder will behave differently than Surly Abrasive), how the beer was treated in transport (I would guess the Surly would originally suffer from more scalping than Pliny the Elder due to longer distance in transportation), how old was the batch of beer when you originally obtained it, what particular hops were used in the beer, are there ‘more’ dry hops than late boil addition hops, and on and on.

  6. draheim

    draheim Poo-Bah (2,461) Sep 18, 2010 Washington

    Yeah, the big problem would be finding a beer I'd be willing to try this on. If I ever get another 4-pack of Abrasive I'm drinking it all within the first 24 hours... :slight_smile: All these variables are duly noted; I suppose the best result I could expect without getting too scientific would be "for this specific beer, hops drop off significantly over x # of weeks/months when stored @ room temp vs. refrigerated." (or not)

    I guess the standard rule of thumb, keep hoppy beers cold and drink them fresh, is sufficient.
  7. drtth

    drtth Poo-Bah (4,006) Nov 25, 2007 Pennsylvania

    A big part of the answer you seek can be found here:

    Vanderhaegen, B., Neven, H., Coghe, S., Verstrepen, K.J., Verachtert, H., Derdelinckx, G. (2003) Evolution of chemical and sensory properties in top-fermented beer during aging. J. Agric. Food Chem. 51, 6782-6790
  8. draheim

    draheim Poo-Bah (2,461) Sep 18, 2010 Washington

    Wish this thread hadn't been moved, this thread is specifically about beers that are not to be cellared/aged. Grrr. Oh well. Thanks for the feedback folks.
  9. KAF

    KAF Crusader (772) Jun 22, 2007 Iowa

    Done this with Surly Furious and Abrasive over a four month span and with Stone 15th Anniversary over a six month span (opened bottles two weeks ago). The Surly beers were noticeably different in aroma and flavor, the flavor in the non-refrigerated can of Abrasive being very mild with Furious less so. The flavor differences as far as the hop profile was concerned was not as significant, but Abrasive was definitely a shadow of itself fresh whether refrigerated or kept warm. The Stone 15 was not as noticeable and I actually enjoyed the nonrefrigerated one more than the refrigerated. Neither of theses were done intentionally as my neighbor and I had gone on a beer run together to MN and Chicago and each picked up these beers. He stores all of his IPAs in his fridge and I just shoved them in the cellar at about 60F. We were clearing out space in his fridge and found the Surly and Stone and decided to do side by sides to see if there was a notable difference.
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