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Thread: "super" preservative hop?

  1. #1
    Join Date
    Mar 2004
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    "super" preservative hop?

    Cheers!! I'm looking into preserving beer better in a more natural way, namely using hops for their preservative effect in a greater role. Currently we know from science that hops have some of their preservative quality from isohumulone--the ionophores disrupt lactobacillus' membranes or something like that---we'll call this factor "Y". I believe however, that the majority of hops' preservative power comes from something other than the bittering acids--we'll call it factor "X". I apologize for I only have anecdotal evidence for factor X, but there's a heck of a lot of it from many, many brews!! I've noticed factor X is directly related to the amount of hops used, not the amount of alpha acids. So I have already increased the shelf life and sturdiness of my beer immensely from a wide range of bacterial foes by bittering my beer with low alpha hops so I can increase the amount of hops used in the boil.

    Unfortunately, you can only go so far with this method, because the vegetative flavor starts to come thru if you use too many low alpha hops. The Belgians knew this, so they would dry out hops in the sun so all of the bittering and vegetative(chlorophyll) was gone, and then they would throw in the bleached out, alpha acid free hops in the boil to preserve a beer without adding the bitterness.(but the hops still had factor X) Its also pretty obvious from experimentation, that whatever factor X is, it only comes out if you boil the hops, not if you dry hop them.

    Soon, I may be doing a rather tedious experiment to see if some varieties have more of factor X than others. But before I do, I would rather not reinvent the wheel!!

    Does anyone know of any research regarding what factor "X" might be? The only research I can find deals with factor "Y". Has anyone noticed a beer starting to have better or worse shelf life, or a different susceptibility to being soured when switching to a different hop for bittering that had a similar alpha acid as the one it replaced? Does anyone have any anecdotal or real evidence as to the existence of any "Super preservative" hops out there? Do you think some preservative power could be related to a hop's ability to resist certain growing diseases? Any speculation welcome!!
    Last edited by sam; 05-10-2005 at 07:30 PM.

  2. #2
    Join Date
    Dec 2003
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    53
    Great question.

    Not an easy answer I’m afraid. Before I begin let’s clear up one possible misconception. Dosing a ton of hops may or may not make your beer more microbiologically stable. The reality is that most beer research is done on typical beer for practical reasons (it’s the majority and it pays the bills). So most discussions of hops and its preservative qualities deal with beer from ~15-30bu. So when we discuss beers in the new North American realm of 30 - ?????? we are in a whole different realm. With that said there are some indications that more is not better.

    Let’s take a moment and remind folks that there are bacteria that ARE hop (iso-a-acid) resistant. For sure Graham-negative bacteria are hop resistant but fortunately they are not so resistant to the alcohol and pH found in beer…now for the exceptions… Pediococcus damnosus which can produce rope and big diacetyl. It is important to note that G- bacteria were more important in the brewing past when O2 levels in finished product were higher than they are today. This may have some implication to small brewers of today whose oxygen levels in package are not in control. For those in this category then other present day atypical brewery bacteria might be of concern…in particular acetic acid bacteria.

    Fortunately most Graham Positive bacteria are hops sensitive. The bad news…Lactobacillus…in particular Lb.Brevis and to a lesser degree Lb.Lindneri are hop tolerant. These buggers are able to produce sourness, rope and haze.

    So you wanna control these buggers with mega hops? The bad news is that research has showed that the hop tolerance is compounding. That’s to say if you expose Lb.Brevis to 15bu, 30bu, 45 bu and beyond that the hop resistant bacteria can adapt to the Bu’s and maintain viability. Interestingly, if the bacterium is propagated serially in mediums with no hop components then the resistance decreases (Richards & Macrae, 1964).

    So now for the original question. Is there a super inhibitor in flavour (low alpha, etc.) hops not normally encompassed in by iso-a-acid effect? Hmmmmmmmmmmmmmmmmmm.

    Iso-a-acid is the boiled result of humulone, co-humulone and ad-humulone. Interestingly it has been shown that the base components have a greater bacteriostatic impact than the isomerized fractions (Walker and Blakeborough, 1952). The bad news is that these components are not nearly as soluble in wort as the iso-a-acids. So how do you get them into solution to provide protection?

    B-acids are the “red headed beaten step child” of the a-acids. They get no respect. In truth for years brewers have valued hops that had a similar % of b-acids as a-acids. This is because brewers have learned that as the a-acids degrade due to age etc. the equally oxidized b-acids miraculously make up the difference and produce the same bitterness (approx.). Oxidized components that may be responsible are humulinone or hulupones (R. Stevens 1985). It is reported that in beer (typical...i.e. the hops have not been aged) that the oxidised b-acids…i.e. hulupones can encompass 1-5ppm (or bu). So it is imaginable if one was to actually age the hops than the bitterness contribution could be greater than the 5pmm cited. Low alpha hops have a greater proportion of b-acids than high alpha hops so low alpha hops can contribute more in this manner. Unfortunately these oxidised components do provide bitterness (and described harshness) which as I understand it, you are not wanting.

    While it appears there is little research that focuses on the oxidized b-acids it is easily conceivable that they would have the same pH motive inhibitory effect on hop sensitive bacteria.

    Hope this helps.

    F.Y.I. primary sources:
    Hops, IOB 1985 R. Stevens (et. al.)
    Beer Spoilage and Bacteria and Hop Resistance, K. Sakamoto and N. Konings
    Last edited by Tbrew; 05-24-2005 at 09:07 PM.

  3. #3
    Join Date
    Oct 2013
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    Ireland
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    protein-polyphenol reactions?

    Is it possible that low alpha hops, because more vegetable matter is required to get the same amount of bittering, enter into more protein-polyphenol reactions than you would get from an equivalently bitter amount of high alpha hops, and because of this more nitrogen is removed from the wort during the boil making the wort overall less nutritious for spoilage organisms?

    I'm actually approaching this topic from a different perspective, which is trying to find out if switching over to (a larger quantity of) low-alpha hops in the boil would improve the non-biological stability of our beer. A sort of get the protein-polyphenol reactions over and done with early sort of strategy. If you're still there, Sam, can you tell me if you noticed a difference in clarity?

  4. #4
    Join Date
    May 2012
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    Livermore, CA
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    I think you need to look at bacterial stability from all angles, not just making the beer less hospitable to the critters. No amount of hops is going to prevent everything as stated before, best practice is to make sure you are not introducing infections along the process path. Look at hoses, shadows in tanks, improperly cleaned filling equipment, etc.

    The other thing to look at, and this is not something to underestimate. You are running a business, and you will loose yield to hops. In reality, you should be doing everything you can to decrease your kettle load so that you get as much of the beer you make into the tanks. Hops soak up a lot of wort. So adding more hops hits you twice, once as the added cost and again with the decrease in yield.

    This is why process is so very important, not just the antibacterial properties of hops.

  5. #5
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    Without adding much to others comments - total brewery hygiene including pitching yeast, and excellent oxygen control during production an packaging is essential. If it is all good, you can bottle yeast conditioned beer and it will not go off for literally years. So looking for hops as the holy grail to compensate for less than really good hygiene is, as has already been said, going to cost more in time, effort and pounds / dollars (name your currency) than the input in hops.
    dick

  6. #6
    Join Date
    Sep 2005
    Location
    Louisville, KY
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    957
    There is no more natural way to preserve beer other than good sanitary technique during production.
    I had the pleasure of drinking this beer two weeks ago. It was still very good, well aged flavors for sure, but clean. Cheers

    Name:  20181111_144002.jpg
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    Joel Halbleib
    COO / Zymurgist
    Goodwood Brewing Co
    636 East Main St
    Louisville, KY
    goodwood.beer

  7. #7
    Join Date
    Oct 2002
    Location
    Chesterfield, UK
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    Courage Imp R S?

    I should have a couple of those from about 95 lurking around. I certainly have some Tennents Lament (18%) we brewed just prior to closing Exchange Brewery, and some Whitbread Celebration (unfiltered 11%) in hand corked bottles - both still drinkable. Lovely sherry characteristics.
    dick

  8. #8
    Join Date
    Oct 2012
    Posts
    31
    I think your whole line of thinking is off. Beer staling is one issue, but bacterial infection is quite another. Are you actually having beers go sour? Are you sending beers for microbiological assay and getting positive results for microbial infection? If not, I don't think that any of what you are looking into matters. If you are, then you have serious hygiene issues in your brewery and should get an expert in to revise your cleaning protocols.

  9. #9
    Join Date
    Sep 2005
    Location
    Louisville, KY
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    You nailed it Dick, that is indeed a Courage. I need to come for a visit to your cellar! Is a beer still brewed under the Courage, or Whitbread name?

    Quote Originally Posted by dick murton View Post
    Courage Imp R S?

    I should have a couple of those from about 95 lurking around. I certainly have some Tennents Lament (18%) we brewed just prior to closing Exchange Brewery, and some Whitbread Celebration (unfiltered 11%) in hand corked bottles - both still drinkable. Lovely sherry characteristics.
    Joel Halbleib
    COO / Zymurgist
    Goodwood Brewing Co
    636 East Main St
    Louisville, KY
    goodwood.beer

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