Diacetyl in New England Style IPAs.

[theheadonthedoor]

I am finding this to be more and more common with the style, and honestly the most off putting flavor I can think of for the style. I get how and why the yeast make diacetyl, and how they attempt to clean it up.

But as I am about to brew my first "NEIPA", I want any advice on how to avoid it being not only a diacetyl bomb, but having any at all. Because if I find it at all, it's gonna be hard to not want to dump it, other than hoping it cleans up quick.

Albeit not a necessarily phenomenal beer, I like how the juicy haze beer from New Belgium doesn't appear to have any diacetyl, and I know that they use American Hefeweizen yeast as opposed to the more common London III/Juice yeast that kicks out tons of that naughty chemical.

Additionally, I hope someone has the time and resources to ferment a NEIPA with all four of the yeasts plausible for one from Imperial (Barbarian, Juice, Dry Hop, Citrus). That would be interesting. Now, I'm rambling.

Thanks for any input and please post pictures of your hazy ipas for me to gawk at.

-Adam Edwards

 

[day_trippr]

I am finding this to be more and more common with the style[...]

Elaborate, por favor.

I live in NEIPA Land. I never get diacetyl notes from Tree House, Alchemist, Trillium...frankly, any of the authentic creators.
For that matter, I've been hammering out neipas for the last year and never get diacetyl.

What have you been sampling?

Cheers!

 

[theheadonthedoor]

I've noticed it in every homebrew version I've tried, which worries me about brewing one. As for professional breweries, I've noticed it tremendously in hazy ipas from Fort George (I love everything else) as well as beers from Revision, Three Magnets, Trap Door, Matchless, and even Modern Times. It's not every beer, but when it's there, it is so apparent and off-putting. I haven't had any of the legit northeast ones, and the best ones I've tried so far were Gimme Da Loot from Revision, What Rough Beast from Breakside, and Juice Jr from Great Notion.

 

[specharka]

Are you sure that it’s diacetyl you’re noticing? There’s quite a few observable esters that I get from NEIPAs, but never diacetyl.

I know I have a sensitivity for isoamyl acetate and ethyl acetate, can’t stand Hefeweizen, some Belgian yeasts or ripe bananas because of it.

 

[bierhaus15]

It is not as uncommon as expected. I've picked it up numerous times in TH and Trillium, although I am quite sensitive to it and have access to a GC/MS to verify it.

One of the common ways it ends up in beer is via dry hopping, where large dry hops added at the very end of fermentation restart fermentation via inclusion of hop derived alpha/beta amylase (hop creep). The yeast goes active active but never gets to clean up the D as the beer is usually crash cooled/canned by then. There is some great research being done on this now at OSU (Shellhammer Lab). Large breweries get around this by testing for VDK like New Belgium. Ways to prevent this are to dry hop earlier or give the beer more time warm when dry hopping.

 

[Upthewazzu]

I think it's a byproduct of the quick turnaround folks use to make this style. Some home brewers/commercial breweries are fermenting them for 7 days or less. It's just not enough time, IMO.

I've made 4 or so batched of NEIPA's and never had any diacetyl. However, I usually let them ferment out for at least 10 days before kegging. Sometimes a little longer.

 

[stickyfinger]

I battled with a bad diacetyl problem in my NEIPAs or just super hoppy IPAs in general for months. For several batches in a row (not just IPAs) I did a qualitative forced diacetyl test. I never had diacetyl after at least 7 or maybe 10 days of fermentation and maturing in primary for the non-hoppy beers. When I added a massive dry hop to beers, I almost always had diacetyl precursors that would hang around for days and days. The beer always tasted amazing when transferring to the keg but the precursors would oxidize sometimes within 24 hrs and ruin the batch. One time I even did a forced diacetyl test on a beer BEFORE dry hopping. There were no precursors. I then did a massive dry hop and tested again after like 3-4 days. The result was tons of diacetyl precursors!

My first solution was to try different yeasts. The only yeast that consistently just seemed to not produce diacetyl precursors was WY1007, a kolsch yeast. The problem was that after several trials I realized I didn't like that lagery flavor profile in my IPAs. wy2565 might be a good alternative as Braufessor has used it in some cloudy, hoppy beers and really likes the flavor. It may have low precursor production; i'm not sure.

My second solution was to age the beers longer, add valine nutrient, and dry hop sooner (w/in 48 hours of pitch.) This sometimes resulted in no diacetyl in the keg but it would often still develop.

What seems to have been the problem? Well, I was using glass carboys at the time, and I would always crash cool them with a rubber stopper in the top. When I stopped crash cooling, the diacetyl problem completely disappeared! I haven't had diacetyl in an IPA since then. I do have diacetyl precursors in the beer. It's almost impossible to completely eliminate diacetyl precursors in super hoppy beers in my experience. The great news as it doesn't seem to matter as long as you prevent oxygen ingress before/during packaging.

Since this awful time in my brewing past, I have started fermenting in corny kegs and transferring using a closed system. I have not had any diacetyl since doing that and routinely cold crash in the primary corny once the beer has carbonated.

So, my hard-won advice to you is to prevent oxygen ingress once the dry hops have been put into the beer and don't cold crash unless you can make sure there is no way for any oxygen to get into the fermenter. If you do that, I think you'll be fine if you keep the beer cold and transfer using a water-purged keg or a fermentation-purged keg.

Other people seem to be able to sloppily cold crash and not get diacetyl. I don't know how they do it. It just didn't work for me.

I've tasted a few commercial hoppy beers with diacetyl. I think it's harder for commercial breweries b/c it's hard to package beer without letting some oxygen in. Also, if it warms up, it is more likely to oxidize the precursors. I swear I even detected some diacetyl in one of the Alchemist's beers one time, a very hoppy blonde ale that they make periodically.

 

[theheadonthedoor]

I battled with a bad diacetyl problem in my NEIPAs or just super hoppy IPAs in general for months. For several batches in a row (not just IPAs) I did a qualitative forced diacetyl test. I never had diacetyl after at least 7 or maybe 10 days of fermentation and maturing in primary for the non-hoppy beers. When I added a massive dry hop to beers, I almost always had diacetyl precursors that would hang around for days and days. The beer always tasted amazing when transferring to the keg but the precursors would oxidize sometimes within 24 hrs and ruin the batch. One time I even did a forced diacetyl test on a beer BEFORE dry hopping. There were no precursors. I then did a massive dry hop and tested again after like 3-4 days. The result was tons of diacetyl precursors!

My first solution was to try different yeasts. The only yeast that consistently just seemed to not produce diacetyl precursors was WY1007, a kolsch yeast. The problem was that after several trials I realized I didn't like that lagery flavor profile in my IPAs. wy2565 might be a good alternative as Braufessor has used it in some cloudy, hoppy beers and really likes the flavor. It may have low precursor production; i'm not sure.

My second solution was to age the beers longer, add valine nutrient, and dry hop sooner (w/in 48 hours of pitch.) This sometimes resulted in no diacetyl in the keg but it would often still develop.

What seems to have been the problem? Well, I was using glass carboys at the time, and I would always crash cool them with a rubber stopper in the top. When I stopped crash cooling, the diacetyl problem completely disappeared! I haven't had diacetyl in an IPA since then. I do have diacetyl precursors in the beer. It's almost impossible to completely eliminate diacetyl precursors in super hoppy beers in my experience. The great news as it doesn't seem to matter as long as you prevent oxygen ingress before/during packaging.

Since this awful time in my brewing past, I have started fermenting in corny kegs and transferring using a closed system. I have not had any diacetyl since doing that and routinely cold crash in the primary corny once the beer has carbonated.

So, my hard-won advice to you is to prevent oxygen ingress once the dry hops have been put into the beer and don't cold crash unless you can make sure there is no way for any oxygen to get into the fermenter. If you do that, I think you'll be fine if you keep the beer cold and transfer using a water-purged keg or a fermentation-purged keg.

Other people seem to be able to sloppily cold crash and not get diacetyl. I don't know how they do it. It just didn't work for me.

I've tasted a few commercial hoppy beers with diacetyl. I think it's harder for commercial breweries b/c it's hard to package beer without letting some oxygen in. Also, if it warms up, it is more likely to oxidize the precursors. I swear I even detected some diacetyl in one of the Alchemist's beers one time, a very hoppy blonde ale that they make periodically.

Great info! I'll definitely take this all into account. I've never fermented in any of my corneys but perhaps now I will. I hear it's the new thing anyways. But it might not fit in my fermentation fridge, which would be a problem.

 

[stickyfinger]

Great info! I'll definitely take this all into account. I've never fermented in any of my corneys but perhaps now I will. I hear it's the new thing anyways. But it might not fit in my fermentation fridge, which would be a problem.

my cornys can even fit in my dorm fridge, so you should see if yours will fit. the only drawback is the fermentation volume is decreased. i have been using anti-foam and can get 4.75G (with yeast starter included in that volume) into the keg for IPAs. I then dry hop when there is little sugar left in the wort or dry hop and add priming sugar at the same time and then seal it up. I transfer using the clear beer draught system after chilling it. i usually do 2-3 kegs at once from the same brew so i'm not doing an entire brew just to get 4.75G before yeast and dryhop losses.

i would gladly ferment in a carboy though as well. just rack the warm beer to a purged keg and you should be fine. I used to remove the poppets from the QD and the keg liquid post when racking to avoid clogging the line at that major failure point!

 

[specharka]

my cornys can even fit in my dorm fridge, so you should see if yours will fit. the only drawback is the fermentation volume is decreased. i have been using anti-foam and can get 4.75G (with yeast starter included in that volume) into the keg for IPAs. I then dry hop when there is little sugar left in the wort or dry hop and add priming sugar at the same time and then seal it up. I transfer using the clear beer draught system after chilling it. i usually do 2-3 kegs at once from the same brew so i'm not doing an entire brew just to get 4.75G before yeast and dryhop losses.

i would gladly ferment in a carboy though as well. just rack the warm beer to a purged keg and you should be fine. I used to remove the poppets from the QD and the keg liquid post when racking to avoid clogging the line at that major failure point!

I would be really hesitant to remove a poppet when transferring to a purged keg. That’s just asking for oxygen ingress.

Alternatively, I really like adding a dry hop charge to a purged keg, performing a closed transfer and setting a spunding valve to about 25 psi when there’s 1-2P left. The natural carbonation really opens up the beer, plus I feel like the aromatic compounds get impregnated in the dissolved CO2.

 

[stickyfinger]

I would be really hesitant to remove a poppet when transferring to a purged keg. That’s just asking for oxygen ingress.

Alternatively, I really like adding a dry hop charge to a purged keg, performing a closed transfer and setting a spunding valve to about 25 psi when there’s 1-2P left. The natural carbonation really opens up the beer, plus I feel like the aromatic compounds get impregnated in the dissolved CO2.

yeah, there will be some ingress for sure. it worked pretty well for me, but i obviously prefer using the closed transfer system with the CBDS. Yeah, I would definitely carbonate in the keg as you suggest. that is a great idea. i never did that when i was using glass carboys as fermenters, but i would do that if i went back to carboys for some reason.

 

[Bassaholic]

I was just listening to a BeerSmith podcast with Randy Mosher about hop biotransformation and NEIPAs. He brought up the point that there are actually sugars in hops and with the increasingly large dry hopping rates there is a need for a longer conditioning time. He recommended letting the beer sit at 68F for a few days after the final dry hopping or dry hopping before terminal gravity is reached. I believe he mentioned diacetyl as a potential off flavor from not doing this as fermentation can restart at lower temps from the sugar in the hops.

 

[day_trippr]

Very interesting stuff. And I may have been dodging that bullet without knowing it.
I do my first ("bio") hopping 24-48 hours after pitching, another round four days later, then do a free rise to 68°F where it sits for four more days sealed up with 0.4 psi of CO2 on top. Then I cold crash for two days (with the CO2 rig still in place) before a CO2-pushed racking to a Star San purged keg...

Cheers!

 

[couchsending]

I reallly wonder if the increase in diacetyl in these beers is linked to the dramatic affect hops have on PH. Huge whirlpool additions will significantly increase the PH of wort into the fermenter. Higher initial wort PH can have some pretty negative affects on fermentation, at least by some yeasts. Then with people adding hops throughout fermentation again raising PH to a high level before fermentation is complete you can raise PH to such high levels before yeast can reduce/transform diacetyl at the end of fermentation. Diacetyl uptake happens faster at lower PH and really struggles once PH hits 4.5. With huge whirlpool additions, large hop additions during fermentation, and the really high FAN content of American 2row you have a recipe for lots of diacetyl in these highly hopped beers.

 

[Upthewazzu]

I reallly wonder if the increase in diacetyl in these beers is linked to the dramatic affect hops have on PH. Huge whirlpool additions will significantly increase the PH of wort into the fermenter. Higher initial wort PH can have some pretty negative affects on fermentation, at least by some yeasts. Then with people adding hops throughout fermentation again raising PH to a high level before fermentation is complete you can raise PH to such high levels before yeast can reduce/transform diacetyl at the end of fermentation. Diacetyl uptake happens faster at lower PH and really struggles once PH hits 4.5. With huge whirlpool additions, large hop additions during fermentation, and the really high FAN content of American 2row you have a recipe for lots of diacetyl in these highly hopped beers.

It's pretty important to hit a low mash and kettle pH when making NEIPA's. I aim for 5.2 in the mash and 5.5 for the sparge water. I've also noticed that flaked malts will raise the pH beyond what the online calculators indicate, so you need to be more diligent when using them to control the mash pH.

 

[malhal]

Does the diacetyl in a NEIPA present as a caramel aftertaste?

 

[day_trippr]

Classically described as a "buttery" or "butterscotch" character, but "caramel" wouldn't be much of a stretch...

Cheers!

 

[G_robertus]

Does the diacetyl in a NEIPA present as a caramel aftertaste?

Depends on how you perceive diacetyl. I'm extremely sensitive and the classic butter only comes out when it's very bad. Butterscotch is a bit closer. For me, it's very close to how some caramel malts present themselves. The distinction is that diacetyl is more slick-feeling and empties out the other flavours as well, especially hops. When I taste/smell diacetyl, I nearly always taste only that. In a very roasty stout it can be somewhat enjoyable, but it needs to be backed up with malt and body. It also needs to be such a tiny amount that could be identified as a crystal malt.