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  • Hop Creep and beer stability

    I brew beer in France. The market here is accustomed to pasteurized industrial beer. Cold storage for beers is basically unheard of. Bars typically store kegs in the basement with line coolers blowing hot air on them. Most distributors store and ship beer warm. Under these conditions, eventually additional fermentation takes place, causing service issues. Kegs which sit at the distributor in the mid-seventies for 4 months or in the basement of a bar in the 90s for a month are frequently so over-carbonated as to be unservable. I'm sure that we're not alone after talking to bars and other brewers, but I'm not inclined to let it go on the basis that we're no worse than anyone else. We almost never have issues with non-dry hopped beers, but dry hopped beers make up the majority of our sales. Kegs stored in the brewery are in a refrigerated container at 4C (~40F). I'm force carbing our kegged beers to around 2.2 volumes to give myself a bit of margin of error.

    We've used a number of different strategies over the last few years. I can't say that one has been better than another in yielding stable beer. Most recently I have been dry hopping our beers warmer with the theory that at some point the enzymes present in the hop material will eventually either degrade or run out of dextrines to operate on. Frustratingly this doesn't appear to be the case. I'm definitely hitting lower and lower FGs, but it can always go lower in the package. Movement of the hop material inside the FV seems to be linked to increased enzymatic activity.

    Allagash and OSU published some slides about this. They talked about dry hopping warmer and longer (which sounds like our strategy). I'm guessing some of the bigger guys manage to filter and centrifuge their beers down to yeast cell counts where fermentation isn't able to kick off again? Is there a product that could deactivate the amylases present in the hops? I haven't seen any data about whether cryo-hops have more or less issues. I also don't know whether the enzymes go into solution in the beer, or are somehow linked the the substrate of the hop material. It seems as though some sort of sterile filtration or pasteurization is the only 100% solution, but I'm looking for some insight or strategies for dealing with additional attenuation caused by dry hopping.

    Here is a small sample of "Dry Hop Creep" articles I've seen recently.

    http://www.qclscientific.com/pdfs/Be...ern%20Monk.pdf
    https://www.rockstarbrewer.com/how-d...mise-the-risk/
    http://brewcon.org.au/dry-hop-creep-dry-hopping/
    https://www.craftbrewersconference.c...lhammer_02.pdf
    https://www.asbcnet.org/events/archi.../Pages/35.aspx

    Thanks,

    Anthony

  • #2
    Consider This one thing

    Dry hopping has gone well and fully over the top.
    Its quite a " trendy " affair.
    It drives the production cost of the beer up without a major benefit, and with large drawbacks as you are noting.
    The craze after dry hopped beers needs to be checked. They are not necessarily " That Great."
    Warren Turner
    Industrial Engineering Technician
    HVACR-Electrical Systems Specialist
    Moab Brewery
    The Thought Police are Attempting to Suppress Free Speech and Sugar coat everything. This is both Cowardice and Treason given to their own kind.

    Comment


    • #3
      Suggestions

      The Brewmaster is suggesting " Late " Hop additions rather than dry hop which I also felt could help your situation.
      Otherwise stop brewing so many dry hopped beers is the way I would go personally.
      It only takes me having one bad beer to stop me from buying anything else from said brewery, ever from that point in time.
      If you Brew one of the best Pale Ales in the known universe, people will always come back around to it.
      But, if you are known to have lots of spoilage problems, it can turn people away from your product for life.
      A lot of people are this way.
      Real Ale is a fine art, without all the trendy stuff going on.
      Warren Turner
      Industrial Engineering Technician
      HVACR-Electrical Systems Specialist
      Moab Brewery
      The Thought Police are Attempting to Suppress Free Speech and Sugar coat everything. This is both Cowardice and Treason given to their own kind.

      Comment


      • #4
        The Dreaded Hop Creepster

        If you want to reduce hop creeping I would recommend the following based on my own personal experience
        1) Dry Hopping Sooner, when yeast are more active and sooner to promote the breakdown of unfermentables to happen sooner. This will help with diacetyl/VDK uptake. I prefer 1-2 Plato before your first terminal gravity(where the yeast would stop eating if you were not to dryhop). FWIW I like to dryhop my IPA’s around 4-4.5 Plato and will usually see a post dryhop terminal gravity of 2.5-2.8 Plato.
        2) Replace some additions with Cryo Hops, I have found less breakdown of unfermentables into fermentables and am of the opinion that most likely most of the enzymes reside in the coarse leafy fraction of the hops.
        Also note, I wouldn’t recommend removing all t90 from your beer, for a balanced ipa I prefer around a pound per barrel of T90, and about 1.5 lb per barrel Cryo(I assume one pound Cryo is ~2 lb t90 equivalent). This works for me but your beers and any Cryo subbing should be based on your personal taste and goals
        3) Mash a little lower, basically the enzymes are going to breakdown the long chain sugars anyway so why add more by mashing high?
        4) Remove Dextrin heavy malts from your grain bill, since a chunk of these unfermentables will breakdown anyway.

        Comment


        • #5
          Originally posted by El Superyeasto View Post
          If you want to reduce hop creeping I would recommend the following based on my own personal experience
          1) Dry Hopping Sooner, when yeast are more active and sooner to promote the breakdown of unfermentables to happen sooner. This will help with diacetyl/VDK uptake. I prefer 1-2 Plato before your first terminal gravity(where the yeast would stop eating if you were not to dryhop). FWIW I like to dryhop my IPA’s around 4-4.5 Plato and will usually see a post dryhop terminal gravity of 2.5-2.8 Plato.
          2) Replace some additions with Cryo Hops, I have found less breakdown of unfermentables into fermentables and am of the opinion that most likely most of the enzymes reside in the coarse leafy fraction of the hops.
          Also note, I wouldn’t recommend removing all t90 from your beer, for a balanced ipa I prefer around a pound per barrel of T90, and about 1.5 lb per barrel Cryo(I assume one pound Cryo is ~2 lb t90 equivalent). This works for me but your beers and any Cryo subbing should be based on your personal taste and goals
          3) Mash a little lower, basically the enzymes are going to breakdown the long chain sugars anyway so why add more by mashing high?
          4) Remove Dextrin heavy malts from your grain bill, since a chunk of these unfermentables will breakdown anyway.
          Hello,
          Apart from those tips, we brew in Spain and share the same problems/fifficulties with the cold chain, we have decreased our carbonation down to 1.8 volumes of CO2, makes our beers better and they have improved shelf live. We also brew pretty much hoppy beers with double dry hopping.
          Hope it helps!
          Jose Argudo
          Head Brewer
          3Monos Craft Beer
          Malaga, Spain
          www.3monoscaftbeer.com

          Comment


          • #6
            Anthony, we have the same warm storage/distribution conditions as you. This has been such a big issues for us - I've visited and talked to countless brewers, read/viewed nearly everything on MBAA (some good district presentations), BA/CBC presentations, and other sources, but there's not yet a consensus on how to mitigate the problem. Some opt for earlier, warmer, longer hop contact to force the reaction to happen as much as possible and get it over with, while some go for a colder, shorter contact time to minimize the reaction and hopefully minimize the problem. We started with the former but are cautiously moving to the latter because we don't want super-dry beers with inconsistent ABV and it takes too much tank time.

            Some of what I've learned:
            - hop contact time matters a lot. But strategies for dealing with it differ.
            - mid-alpha hops are the worst: Amarillo, Centennial, etc. Some have completely eliminated their use.
            - agitation/recirculation will increase enzymatic reactions.
            - yeast cell count when dry hopping. Many breweries lower cell count through crashing to ~15C, then dry hop with a low cell count and short contact time, then ideally centrifuge to reduce hops and yeast in the package further for stability. I've seen two examples of centrifuging PRE-dry hopping to reduce the cells/ml below a threshold, for breweries who have a non-flocculating yeast.
            - VDK is a good proxy for the enzymatic reaction taking place - a VDK spike means that re-fermentation is happening. Re-fermentation means that the enzymatic reactions are occurring. If you know when the VDK spike is done, you can immediately crash and separate out as much hops (and yeast) as possible for a more stable product. Measuring total VDK, using ASBC-25B, requires a spectrophotometer, but is the most accurate method (beyond gas chromatography) for determining what is going on. http://methods.asbcnet.org/summaries/beer-25.aspx

            Comment


            • #7
              I get the impression that Rockstar are blaming increased diacetyl on the hops themselves. I think he is forgetting that diacetyl is produced when yeast is actively fermenting, which takes place after an oxygen addition. If the hops are not fully deoxygenated, and whole hops would be particularly difficult to deoxygenate before addition to beer, then it is not surprising they are detecting increased levels of diacetyl. So to eliminate the diacetyl part of the problem - as mentioned, a few degrees SG (1 or 2 plato) at time of dry hop addition will help the yeast convert the diacetyl to acetoin so not be anything like as noticeable.

              If I was having to put up with shelf lives of a few months in those conditions, then I would seriously look at filtration prior to kegging, possibly even sterile, which whilst not eliminating the enzymes, will at least remove the yeast and, if sterile filtered, the bacteria which can lead to other problems in addition to the enzyme problem.

              As an aside, the cost of kegs in trade is simply horrendous if you own them, so I would simply not consider sending out kegs unless you know you are going to get them back in just a few weeks - which should also help to alleviate the additional attenuation problem. I am guessing that even if you hire the kegs, then hire costs are related to the time in trade.
              dick

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              • #8
                Oh yes, I meant to say, thanks for all those references.

                Cheers
                dick

                Comment


                • #9
                  Hello everyone,

                  Thanks for your time and experience.

                  Starcat, it's our experience that all or nearly all aroma from late kettle/whirlpool additions go out the airlock with the CO2. It smells wonderful in our brewery when the beer is fermenting, but non-dry hopped beer is not hitting the notes we want. We brew the beer the way we want it. The fact that it sells is not the important determinant to us. Taste is opinion, not fact. If you're getting the results you want, more power to you. We don't with out dry-hopping though.

                  ElSuperyeasto. Thanks so much for your input. We are already doing a number of these things, but I have the suspicion that for some reason mashing higher still gives us higher FG despite the DHC (Dry Hop Creep). We tend to use little or no Dextrin malts since I tend to believe that these tend to be broken down in the mash anyway, and are useless. I agree with your observation on the Cryo hops. We see less creep with them, but I wonder if it has something to do with CO2 nucleation. I've always thought that the were supposedly 1kg cryo = 2kg T90. That's what the price and AA% suggests anyway. Maybe, I'm missing something. I'll go back and do a bit more research.

                  Jose, we definitely go lower with carb, but I'm pretty sure our bars would return fresh kegs to us if they only had 1.8 vols of CO2. We already get some negative feedback from kegs at 2.2 volumes. People here are used to Belgian beers. Carb seems to be very important to them.

                  Scotts, we're definitely doing the longer warmer option currently. It does destroy us on tank time. We're always pushing 4 weeks down from 3 weeks previously. I completely agree that agitation has a big impact. We have a hop gun and up to now we have always forced all the pellets back into the tank (we get better aroma that way). I wonder if we should do a second pass with the filter candle after a few days to recover a maximum of hop material back into the hop gun? That's interesting what you say about VDK. We don't have a Spec, but we're doing forced VDK tests (20 mins at 60C followed by cooling). Beers are clean pre-dry hop, then go through a period post dry-hop with high levels of alpha-acetolactate (based on VDK test results) then after gravity has stabilized go clean again. In our experience, lower dry hop temps (17C vs 20C) give us longer periods of high alpha-acetolactate.

                  Dick, I have to reread the article. If so, clearly they are wrong. The enzymatic reactions are clearly kicking off a new fermentation with renewed alpha-acetolactate production. I don't think that oxygen ingress from dry hop is the problem. I think all of us are getting some micro oxygenation at packaging which is enough to get the alpha-acetolactate to transform into diacetyl. Dick, in the European market, we use a huge number of one-way kegs. We only work in stainless with a small number of local bars. Everything that leaves the Paris metro area is in a one way keg. They're ~15€ a piece for a 30L (France bans all kegs larger than 30L). We have relatively few issues with our stainless kegs for the reasons you have observed. The one-way kegs we use are the bag-in-box type which have the annoying characteristic of being even more sensitive to poor storage. Because there is no dip tube, any bubble of CO2 escaping solution leaves through the service line, which causes big problems when it eventually finds its way out of the faucet at 1/3 the ambient pressure.

                  With early, or very early dry hop addition, you don't get the feeling that yeast are pulling down a significant amount of your hop aroma? Our strains tend to floc hardest at about 0.5p away from TG (not counting eventual TG post dry hop).

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                  • #10
                    A common method growing here in the US is very early dry hopping, ie, on day 1 or 2 of fermentation. The result is referred to as biotransformation. It's not very well understood but it does seem to favor those juicy/hazy New England IPA that are all the rage (my brewery is in New England and you can't survive these here without making one it seems).
                    That being said, when i've used this method I still do a more traditional dry hop at the end of fermentation. the biotransformation does a lot for flavor but it seems that a lot of the aroma gets blown off during high krausen.
                    All of our accounts store our kegs refrigerated so we fortunately haven't encountered this problem.
                    Good luck

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