Anyone notice diacetyl from Big dry hopping?

We have done a lot of research on this as we were having some post packaging diacetyl issues when doing late dry hops on IPAs. Basically hops (especially ones with high oils contents) contain certain chemical compounds that can leave diacetyl precursors in finished beer. Certain yeast strains can further cause the compounds to develop into diacetyl and not be active enough to clean it up. There is also research that suggests the oxygen induced when dry hopping can activate fermentation enough to creat diacetyl but not clean itself up. Our beer showed zero signs of diacetyl even when doing all of the standard tests and long d-rest, however heavily dry hopped beers would sometimes develop noticeable levels after about 5 days in packaging at cold temps.

We solved our issues by dry hopping during or at the trail end of fermentation for all of our dry hopped beers. 300 batches later and no problems but we do shy away from certain practices and yeast strains that we used to employ.

 

You're back. Don't know if anyone else acknowledged it.

There was a discussion of this at a talk a HomebrewCon. I ran across the old British paper some time ago.

 

Same as "hop creep" discussion again? (See Brut IPA thread)

 

Yup, hop creep. Hops contain enzymes. If those hop enzymes wake up the yeast again, could get diacetyl, as well as lower FG, increased carbonation, you name it.

 

I attended HomebrewCon 2018 in Portland. OR and I attended a presentation which summarized four different MBAA presentations and one of those was on the science of dry hopping. During that presentation the presenter mentioned that one brewery (Bridgeport?) learned they need to extend the dry hopping contact time to 8 days to permit the diacetyl developed during dry hopping to be reduced below the flavor threshold level.

Cheers!

 

I posted the below in a previous thread:

Here is another discussion about Dry Hop Creep:

https://www.rockstarbrewer.com/how-...n-beer-and-how-brewers-can-minimise-the-risk/

Cheers!

https://www.beeradvocate.com/commun...rican-on-enzymes-in-hops.590134/#post-6206593

 

In my 5-6 gallon batches, upwards of 8-10oz have been used for dry hop. Never picked up diacetyl, personally. I typically add the dry hop with a few points left so the yeast can scrub any O2, hopefully. It's been working well for me, at least.

 

I never had diacetyl issues show up in my bottles back when I bottled. I have had about a half dozen instances of finding diacetyl in kegged beer. I think there are several possible factors at work that could explain my success in bottle conditioning and my occasional kegging failures.

-addition of simple sugars - maybe? Someone with some biochemistry would need to evaluate whether yeast fed simple sugars are more likely to get more active, sufficiently so to completely mop up any diacetyl produced by the fermentation of the sugar. Or maybe less diacetyl gets produced when fermenting simple sugars, as opposed to whatever happens when hop enzymes start to work on dissolved carbs to produced sugars that yeast might use.

-extended warm period during bottle conditioning. I would give bottles 3 weeks to condition before cooling, and I would crack a few bottles at that point to make sure. When I keg, I am much more eager to cool down and carb up.

-another possibility I could entertain is that I have become better at detecting diacetyl in beer over time, but I stuck with bottling for a good long time, 8 years, so I feel like I would have learned to notice it in that stretch/

I'd be interested in any thoughts on these possibilities.

 

I got diacetyl from dry hops just one time. It faded after a month or two.

 

Yeah the yeast cleaned up any potential diacetyl when refermenting in the bottle.

Changed my dry hopping methods 4 months ago or so. Every now and again I’ll add a small amount at the tail end of fermentation but most of the time I’ll wait til fermentation is done, test for VDKs, then crash to 55, wait a day or two, harvest yeast and add dry hops and keep the beers between 58 and 63 for 4-5 days then crash, transfer, and force carb or krausen. All those hoppy beers got between 6 and 10oz of dry hops.

I never picked up any diacetyl until just recently. I split a batch at kegging. Force carbed one half and krausened the other half. Just a little experiment to see how the different process changed the outcome. Ended up with a small amount of diacetyl in the force carbed keg. Not a butter bomb but had that tell tale slickness. Krausened keg was totally fine.

Certain hops are more prone to it than others. I believe I’ve heard that Mosaic and Centennial were some of the worst offenders. But I’ve also read that it varies by crop. I believe it was the Ekuanot in this last batch as the other two were Aussie hops and I’ve never experienced it with Southern Hemisphere varieties.

I think certain yeast strains are more prone to it as well. A couple time this summer I had 1318 finish a little high and I actually tried to get some hop creep with a bunch of Mosaic at 68 but it never happened. No drop in gravity at all.

Great MBAA podcast on this topic with guys from OSU, Bell’s, and Allagash. Brewers from Bell’s recently released a paper on their research around it but I don’t feel like paying the $50 to read it.

 

Was the beer kegged and cold when it faded? I'm trying to decide how to deal with diacetyl in Barleywine right now.
(1) Keep it in the keezer and wait,
(2) Pull it from the keezer, let it warm up, and wait,
(3) Go nuclear and do 2 plus add some krausen.

I've always gone nuclear in the past, with success. Curious if waiting longer (warm or cold) would have seen the same results.

 

Never gotten D from any ale yeast that I can remember...but then I ramp up, store for 2 days at room temp when kegging, and lager everything...oh, and I average ~12 oz hops per 5 gal batch of IPA...usually with at least a small bittering charge.

 

If I am doing a big dry hop 5-6 oz for me, and if is citra, simco or Galaxy, I need to drink it in 6 weeks or it will change and not for the better. Hop nose fades and I get a strain the bitter blanket effect which means mine do not care for.

So I use no more than 4 oz unless it's cascade chinook Columbus or centenial. No Nasty effects from those using up to 5-6 oz.

 

You should always be skeptical, questioning, because science is always imperfect and subject to revision. But it is still the best game in town.

 

I choose to view scientific efforts like I do any analytical effort – analysis is predicated upon a set of assumptions and the results must be viewed in this context.

Cheers!