Guidelines for hop biotransformation

Discussion in 'General Brewing Discussions' started by toffle, Mar 15, 2021.

  1. toffle

    toffle New Member

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    #1 toffle, Mar 15, 2021
    Last edited: Mar 15, 2021
    Hi folks!

    I'm just wondering if anyone has any guidelines or experiences they'd like to share regarding biotransformation dry hop additions? I've done it with NEIPAs but not any other style. There appear to be lots of studies on the process, but it's a lot of data-sifting to decide what the science means in terms of your average homebrewer indulging their hobby.

    So my question is, what are your real-world experiences, recommendations, hidden tricks or cautions regarding this process?

    My one concern is that with dry-hopping at high krausen, and the recommendation to not let the hops sit too many days on the yeast, I may not have sophisticated enough gear to effectively use biotransformation. (I'm not fishing for reasons to upgrade my kit. I've already got enough cleaning to do on brew day!)

    I've been through the following (at least in a cursory fashion):.

    http://scottjanish.com/examination-...s-for-achieving-maximum-hop-aroma-and-flavor/

    https://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/51185/ParkinEllenJ2015.pdf

    https://www.goodbeerhunting.com/blo...-understanding-hop-compound-biotransformation

    https://brulosophy.com/2017/01/23/biotransformation-vs-standard-dry-hop-exbeeriment-results/

    I'm looking forward to any advice on this topic.

    Cheers,
    Tom
     
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  2. HighVoltageMan!

    HighVoltageMan! Well-Known Member

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    I have tried dry hopping at high krausen and didn’t care for it. The flavor and aroma was diminished compared to hopping when the yeast drops out. I do take advantage of biotransformation by large whirlpool additions, more hop compounds are available compared to dry hopping. Scott Janish has a blog about hops along with other brewing research. He is a pro brewer and does not dry hop at high krausen due to lower aroma and hop flavors. He does whirlpool however.

    You can listen to several podcasts on Brew Strong where he talks about this. He also wrote a book “New IPA” where he gets pretty technical and goes into great detail about hops.
     
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  3. toffle

    toffle New Member

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    #3 toffle, Mar 15, 2021
    Last edited: Mar 15, 2021
    Thanks for your perspective. It's the personal experiences which help fill in the gaps between the charts and the numbers.
    I've seen Scott's name in some of my reading. I will spend some time with his blog.
    [EDIT] I just figured out that Scott is "Janisco", who has been posting on the subject around the web.
     
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  4. HighVoltageMan!

    HighVoltageMan! Well-Known Member

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  5. Craigerrr

    Craigerrr Well-Known Member

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    It is also a matter of the style being brewed and personal taste.
    I do two separate dryhop additions during active fermentation for NEIPA. The two additions equalling roughly 11-12 grams per liter. For a more traditional IPA, I will do one addition late in fermentation, and another a couple days later. Usually 10ish grams per liter.
    I have been very pleased with my results per above.
    As for the actual science of it, can't help you there.
     
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  6. toffle

    toffle New Member

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    Thanks so much! I've got loads of science. I even understand some of it. (It's 50 years since I studied organic chemistry in high-school) What I really appreciate is the real world experience, especially from small-scale home brewers who are probably dealing with some limits imposed by their gear. It's pretty much a given that what I'm trying to do would be a lot easier with more sophisticated equipment, but that is not where I'm heading with this at all. So without the ability to remove the hops once added, my concern at is how long I can leave the hops sitting on active yeast before I start having adverse affects on my beer.

    Cheers!
     
  7. Frankenbrewer

    Frankenbrewer Well-Known Member

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    With the beers that I dry hop, I have done 2 or 3 hop additions and have done both, one of those at high krausen and after the yeast is done and the rest about 3- 5 days left to final gravity. The results of both have been pretty good.
     
  8. Group W

    Group W Well-Known Member

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    This is a vast subject with many unknowns, variables and opinions. I’m very interested in what others offer here as well.

    Much depends on the goal of the brew. Is it haziness, hop flavor, NEIPA style, WCIPA style, BT in non IPA beers like pales, ambers, blondes, etc.

    I brew mostly IPAs and seldom brew NEIPAs. Like you @toffle, I don’t have the ability to drop yeast or hop trub from my fermenter. I use a ss brewbucket. Typically my fermentation’s last about 7 days before I cold crash for two days, then keg on day 10. For NEIPAs I DH on day 2 and day 5. So BT hops are in the fermenter with yeast for 8 days. I’m not sure what impact the 2.5 days of cold crashing has on the BT hops other than dropping out haze that would otherwise drop in bottles or kegs. The commercial brewers that I hang with swear by hopping at high krausen for haze (with oats and wheat in the grain bill and medium or low flocculating yeast). They drop the trub with the BT hops after 2 days.

    As for WCIPAs, I like to DH on day 4 when fermentation is dropping off. It lets any O2 introduced with the DH get consumed by the remaining yeast activity.

    Not sure if this helps. But throwing it out there for starters. Cheers!
     
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  9. toffle

    toffle New Member

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    Thanks guys!
    I’m on my phone right now, so I’ll read your responses more thoroughly later. Up to now, I’ve only done single dry hop additions - in the last 3-4 days for most beers, and on day 2 or 3 for NEIPA.

    Another question I have on the subject is whether to do an extra addition of ascorbic acid and yeast nutrients at dry hop time - ascorbic to lessen the possibility of oxidation, and nutrients to encourage interaction between the yeast and hops. Thoughts?

    Cheers!
     
  10. HighVoltageMan!

    HighVoltageMan! Well-Known Member

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    If you are dry hopping during high krausen, there is no need for any antioxidant such as ascorbic acid or sodium metabisulfite. The yeast are the best antioxidant available to brewers. Ascorbic acid is probably not the best antioxidant in beer, it's thought that SMB (sodium metabisulfite) is better. I use that in lagers at a rate of 250mg per 5 gallons with no big issues (I'm not sure it works). I thinking that I could go as high as 550 mg per 5 gallons, but I haven't tried it. I don't want to exceed 10ppm of SMB.
     
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  11. Mark Farrall

    Mark Farrall Well-Known Member

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    I keep hearing biotransformation characterised as two things when we're talking about dry hopping, when really there's 100s of different ones that affect how the dry hop works. The first one everyone was excited about was that some yeast create an enzyme that could change more floral hop oils into fruity hop oils.

    Then with an influx of interest in late and dry hopping academics got better equipment and found that using newer hops, other yeast enzymes could free hop thiols that would give the explosive fruit aromas that are currently fashionable. I've even listened to people genetically ramping up the creation of that enzyme in California ale yeasts so that you can get those thiols out of your grains and just use hops for generic bittering.

    So there's the specific biotransformations that you can take advantage of and there's the other, more process based, steps that can support or create their own biotransformations. I think of them as various post boil additions, This, sadly, ignores the boil additions, though there's a bunch of science that shows they can really change the taste of the beer.

    Post boil is great for getting in materials that later dry hops can take advantage of (lipids and polyphenols) and depending on the hops you use can draw out various materials that will influence the beer significantly.

    Dry hopping in active fermentation provides the enzymes with something to work on if you're hoping for those oil or thiol changes. This doesn't need to be a big dry hop, but it needs to happen during active fermentation if you want to maximise your chances of getting those changes.

    Late or post fermentation dry hops are the ones that leave the aroma in the beer. I've also been playing around with doing these shorter and at cold crash temperatures. Not sure about this yet, but the first few were worth repeating.

    I'll use all three in hazies, For more West Coast IPA like beers I'll decrease the post boil, skip the active fermentation and ramp up the late dry hop. I'll just use the late dry hop for some of the sours and saisons I make.

    And I'm always trying different yeast and hop combinations to see which ones I prefer. Also start off with larger hop amounts than you think is reasonable, then cut them back to see what point you prefer.

    And, ultimately it's preference. You may hate guava so having heaps of thiols that remind you of guava is probably something to avoid, even if it is the height of current brewing fashion.
     
  12. toffle

    toffle New Member

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    Thanks so much all! There's some very good advice here. The science of homebrew beer has taken momentous leaps since I first watched my dad brew some six decades ago.

    One difficulty in all this is it comes down to gaining the experience necessary to recognize which esters, thiols, bio-engineered hops, yeasts, etc.(not to mention the proportions, temperatures, timelines or what have you) are going to lead to desirable or undesirable flavours or aromas.

    This is why I'm bringing this question to you all. Maybe there's someone out there who has done a biotrans addition to an English Bitters! I can't picture it, but perhaps the right alchemy could produce awesome results.

    Cheers,
    Tom
     
  13. Group W

    Group W Well-Known Member

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    Even with high flocculating English yeast the English Bitter would likely be hazy and not to style. There is a beer called Mac & Jack’s African Amber that likely uses BT to haze that beer. Looks dreadful and tastes okay. I think of BT in the context of making a hazy beer. Maybe a hoppy wheat beer could be a candidate.
     
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  14. Mark Farrall

    Mark Farrall Well-Known Member

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    The only way I've found to shortcut some of the experience side of things is to read the people who talk about the sensory side of the equation. While we can put in a certain hop and yeast that may give me a higher level of citronellal, can anyone taste the difference? If they can't then maybe it's not worth spending a batch on that. Or the other way around, someone talks about a batch they brewed attempting to emphasise a certain character I like, then if it's successful I'll try and take that.
     
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  15. 56 Firedome

    56 Firedome Active Member

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    1st off, Thank you @Mark Farrall & @HighVoltageMan! A tour de force of information regarding Hop Biotransformation. A subject I had heard of but never experimented with.
    I Dry Hop almost every brew but I do it in Secondary Fermenter. I also do whatever Clarification there. My intention is to leave as much detritus out of the keg as possible.
    Several comments regarding removal of hops from the Primary Fermenter after some number of days to prevent "grassieness". Whether in Primary or Secondary use a Hop bag. You can remove it when ever you think proper.
    Yes, the Carboys neck makes it hard to remove the bag. So, I made "skinny hop bags" that will come out of the neck with a little encouragement. I use an ss ball bearing for weight. Each can hold an Oz of Hop pellets.
    I don't let them little Hop Crumbs float loosely in either Fermenter to clog up the keg Beer Pickup tube or Drop out from the Gelatin.
    I use a FWH & Whirlpool / Steep hop stands as well as the Secondary, so I may not be achieving BT but I get a lot of Aroma as opposed to Taste from these additions.
    Thanks again for all the info & relating your personal experiences.
     
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