Attack of the Off-Flavor (Hop Burn?). Help!

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mjmcconn

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Howdy all. I've been brewing for years and have had what I think is the same issue on and off and it's driving me so crazy I'm about ready to quit. The issue is I almost always get a bitey bitterness, back of the tongue and a bit sour and dry, that ruins a perfectly good beer with a gnarly aftertaste. It doesn't taste like any kind of bitterness I've had from a commercial beer that I can remember, though a few craft brews might have had a bit of it, just not nearly so noticeable. Most recently I've been making SMASH recipes to try and isolate the variables at play. I've made three: Vienna Hallertau Blanc, Pilsen Mandarina Bavaria, and Munich II Falconer's Flight. All fermented with Voss Kveik in a 2.5 gallon unitank keg with a little conical and yeast catchment at the bottom. Every one has fermented full out within a week and after a week or a bit sooner I have CO2 purged after check the gravity and installing the dip tube and then crash cooled, removed the catchment, and carbonated to serve. And every single one had the same flavor. I think it's hop burn but I took a lot of steps to prevent it with this last batch (the Munich II Falconer's) and the off-flavor is still there, just less prominently. Here's some details on that Munich II recipe. Hoping someone has some idea what this is and how to deal with it. I'm so frustrated I'm considering doing a recipe with ZERO hops to see if the flavor is still there.

Water: Distilled bottled. Adjusted pH to 6 going into mash and it came out low (5.05) after the mash.
Boil: 90 minute, all falconer's flight, all added into a stainless steel mesh hop tube: .25 oz @ 45, .25 oz @ 15, .5 @ 10 (with whirfloc), .5 @ 5, .5 @ flameout.
Cool: Used wort chiller to bring it down to 90-95 degrees in about 15 minutes. Transferred to keg through mesh strainer, which picked up almost no particulate. OG was 1.055 (I was expecting 1.059).
Ferment: Pitch 6 tbsp of yeast nutrient and kveik starter with 3/4 tsp of yeast (I think this was about 1/3rd of the packet) that had been fermenting some of the wort for 30-60 min, which was about right to get it going. I opened the pressure release on the keg almost all the way for the first 24 hours because it's Kveik and probably would have exploded otherwise. Then as the fermentation slowed I gradually tightened that pressure release down to around 15 PSI, making sure to never let all the pressure off so there was always CO2 inside and no oxygen.
Carbonating: After a week I closed the butterfly valve to the yeast catchment, popped the lid of and got an FG reading of 1.012 (though come to think of it I'm not sure I adjusted this for temp, in which case it might have been more like 1.014). I attached the dip tube and put the lid back on and purged the head space with CO2. I opened the valve again and stuck the keg in the back of my beer fridge on the second to coldest setting for 48 hours to drop out all the sediment. It looked good in the catchment so I closed the valve, turned the fridge back to the 4 instead of 5 (i.e. warmed it up a bit), and carbonated it at 20 PSI for 48 hours before dropping the PSI down to 11 (I actually let some pressure off before turning it down because it seemed over-carbed off the tap).

It's been about 12 hours now since that last step and, yup, the off flavor is still there, just not as prominent as the two beers that came before (so it seems some of my moves to lower the hop bitterness did help, just didn't solve the problem). This one is looking hazy at the moment, but the other two before it came out clear though and had the same flaw, so I dunno if that's actually hop matter in suspension of yeast or chill haze etc. etc. ...

One more weird thing: Each of these beers has had a white grape smell and a less noticeable but present white grape flavor. I've run Voss Kveik in a cider and there was none of that, so I assume it's the hops but I've never heard of this flavor coming from the 7 c's in Falconer's Flight (I can imagine it being a flavor in Hallertau Blanc and Mandarina Bavaria, though it isn't listed on the flavor profile for those hops). The hop profile also seems to be low on the flavor/aroma side and higher on the resinous/spicey/earthy side with every one of these recipes.

Matt
 
Sorry, 6 teaspoons of LD Carlson yeast nutrient. I know the rec for 5 gal is 1 tsp, but this is Kveik so I went really high with the yeast nutrient. Probably way too high though. I've also been gradually stepping the amount of yeast nutrient up, it hasn't been consistent across the batches that have had the off-flavor. But do you think too much nutrient could negatively impact the flavor?
 
Have you considered that it may be the yeast strain? I get a flavour from Kveik that I can only describe as a harshness, or twang/tartness, or something. I guess it could be described like the hop burn I have had from other beers that I have heavily dry hopped and tapped too early. Maybe try a different yeast and see if that works for you...?
 
I'll give it a shot, but I don't think that's it, just because I used the same yeast in a cider and didn't have any issues at all.
 
2 thoughts that may or may not fit into what you are tasting.

1. Yeast nutrient is important in wines, ciders, and meads as these are lacking in the nutrients the yeast needs. Wort already contains the nutrient needed so adding more may change the flavor.

2. Hop particles are so near the same density as the beer that it can take a long time to settle out. Give your beer more time in the fermenter and see if that changes the after taste.
 
I know you said distilled water, but are you adding salts to adjust pH or just acid? Just wondering about your sulfates to Cholorides, as that would effect perceived bitterness.
 
Thanks y'all,

RM-MN:
1) Kveik is pretty nutrient hungry since it was bred to ferment high gravity beers. From everything I've heard you want to feed Kveik a lot of nutrient if its fermenting regular ABV beers or else it goes slow/stalls out. Having said that, I'm scratching my head about the 6 teaspoons of nutrient I recorded in my notes because it is wayyy too much. Wondering if I wrote down the wrong number or just added too much by accident. Will do substantially less next time (1 tsp would be double the recommended amount for a 2.5 gal batch, 2 tsp would be 4 x the recommended amount).

2) The hop particle settling thing makes sense: Kveik ferments fast, so I've only been giving these beers a week rather than two in the fermenter, and it also ferments hot, so I've only been dropping the wort temp to 90-100F before pitching, which is maybe failing to drop out as much hop matter. I thought that using a hop basket/hop spider plus crash cooling for two full days would solve this problem... but maybe not.

DannyBoy: To reduce pH for the mash I use gypsum and calcium chloride and pH 5.2 buffer solution. For my most recent beer I added one gram of each and this brought the pH down from 7.8 to 6 before adding the grains. After mashing the wort pH was 5, which is a bit low. I also recently learned that Kveik lowers the pH more than other yeasts, so maybe the finished pH on these beers is just low and impacting flavor. I'll check.

Re: Sulfides and Chlorides: I don't have any gear to check this, but I know exactly what you're talking about. How do you measure these aspects of your water chemistry?

Matt
 
: Sulfides and Chlorides: I don't have any gear to check this, but I know exactly what you're talking about. How do you measure these aspects of your water chemistry?
It's more a calculation than a measurement. Once you know what your baseline numbers are, regarding the mineral levels of your water, you can then make your salt additions off of those base numbers; and likewise manipulate your water profile to suit the style you're brewing. I focus alot on sulfates:chlorides, as water with a higher concentration of sulfates pushes percieved bitterness/dryness, whereas chlorides promote a fuller/maltier percieved mouthfeel.

In your case here tho, you're not making a large enough addition that would really push it one way or another, so I doubt thats the source.
 
Have you tried a non-hoppy beer? Say, a Vienna SMaSH with just a bit of Magnum at 60 for bittering? (Maybe a little Magnum at 15, too, but a little. Magnum works surprisingly well in late additions.) This would help settle the question of whether it’s hop burn.

You didn’t ask, but I’ve heard nothing good about buffer solution for stabilizing mash pH.
 

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