Grassy taste - any thoughts?

[soccerdad]

In about 100 batches of home brew I have never had a grassy taste. Until now I' m drinking the beer but might dump the final 2 to 3 gallons.

I seriously don't know if it was bad luck with hops or something bad in my process. Appreciate any thoughts you all might have.

Hops used were Magnum, Columbus, Cascade. These hops from the same lots have been used in other beers with no ill effects. I tend to have these three around in either half pound or pound plus quantities. They are always stored in the fridge or freezer.

There was a flame out addition (Cascade) and I may have let them sit too long. I no chilled this batch (overnight cool down), and although it is not in my notes, I think the hop sock was still in the wort the next morning. I just set the kettle aside to cool on its own and never pulled the bag.

I kegged this batch and I always purge the keg of O2 as I add CO2, but I never know how well purged it is. Then this keg sat for a few months as others butted in line ahead of it. Oxidation could have played a role.

So all I can think of is a) poorly stored hops but that is my least likely. b) boiled hops sat in the wort too long or c) oxidized in the keg. Am I missing something?

 

[Singletrack]

I have used no chill several times with loads of hops in the wort, and I have not had grassy flavors. Did you cold hop (aka dry hop)? The only time I have had grassy flavors was when I cold hopped too long with leaf hops.

 

[Stillraining]

I keg hop a lot and even leave them in till the keg kicks a lot as well...there is always a grassy taste after dry hopping to me at first, but it settles out within a couple weeks and does not come back but very, very rarely. Citra seem the worst for me so I tend not to leave citra in the keg..
But it does not look like you dry hopped this batch, so you probably have already identified the culprit with your changed process. And FWIW I dont do much of anything for O2 reduction so I doubt that is it. All I do is add priming sugar to the kegs and let sit at room temp( 66 to 70) for a week to help eat up O2 but other wise its splashy splashy both hot and cold side.

Go back to your normal process and chalk it up as a learning experience. If the next batch turns out the same then its the hops.

 

[soccerdad]

No dry hop with this recipe ,.. and I have keg hopped without getting the grassy taste.

I was thinking that there might be a ( significant) difference between hops going in at 200+ degrees and sitting in the wort versus hops going in at 70 degrees and sitting in beer .. I dunno ?

 

[Stillraining]

Its possible I guess...until you brew another batch your old way with the same hops you wont know. We will all learn from it.

 

[day_trippr]

[...]I was thinking that there might be a ( significant) difference between hops going in at 200+ degrees and sitting in the wort versus hops going in at 70 degrees and sitting in beer .. I dunno ?

Theoretically, there's a rather large difference.

Isomerization begins around ~180°F, so a 200+ addition will crank up the IBUs until the temperature drops below ~180°F. As well, the more volatile hop contributions (like farnesene, myrcene, etc) may be "cooked" out of the wort with extended exposure to 200°F, with aroma being the first to go, and eventually flavor notes will attenuate.

That's at least one reason why folks dry hop, to put back the most frail hop characters that got lost at higher temperatures - or got scrubbed by the throes of fermentation.

Don't know if or how that all relates to the "grassy" thing. Excessive myrcene in hop oil is one of the primary compounds associated with "grassy", but it's about as volatile as farnesene. If anything it should be more problematic with protracted "room temperature" dry hopping than what was very nearly a Flame-Out addition...

Cheers!

 

[soccerdad]

Theoretically, there's a rather large difference.

Isomerization begins around ~180°F, so a 200+ addition will crank up the IBUs until the temperature drops below ~180°F. As well, the more volatile hop contributions (like farnesene, myrcene, etc) may be "cooked" out of the wort with extended exposure to 200°F, with aroma being the first to go ...

So d_t, give me your thoughts on this .. maybe I could or should adjust. When a recipe calls for Flame Out hops, I cut the heat, throw the hops in, and in 15 minutes or so, with no heat, the kettle is down to maybe 200 degrees. On the other hand, if a recipe calls for a hop stand, I will chill to 180 (prox), stop the chill, wait maybe 20 min, pull the hop stock. Temp at that point is usually nearing 150, and I resume the chill.

I know there are some brewers who say, "take all the late additions, and put them in a hop stand." Although I am not averse to that idea, I don't always chill. However, I am rethinking that if not chilling might risk grassy taste. One in a hundred makes me think I should not point to no chill as the culprit here, but I do want to reduce any and all risks.

 

[day_trippr]

Your FO and WP schemes are clearly in the ballpark. And as I have zero experience with leaving hops in hot wort 'til it cools (over a long period) to pitching temperature, I can't logically finger that as a route to grassiness.

But it is outside of a traditional hopping approach, so I'd consider it suspect until you can repeat the same process without a grassy result...

Cheers!

 

[JONNYROTTEN]

I did a little exbeerament awhile back.
I split a double batch
One I pulled the 160 deg hop bag out
One I left in the fermenter while it chilled overnight from 100 deg to 65 to see if I could get the most juiciness out of the hops.
The batch that was left in the fermenter overnight had a harsh grassy taste....first and last time I tried that.

 

[bkboiler]

i wouldnt dump it just yet! in my experience my heavily dry hopped and keg hopped beers are green for a week or so then peak after a couple weeks and need to be consumed within a month after that.

 

[JCrazy84]

Small sample size, but I have found that if I am making an APA or a Session, or anything below about 1.055 and have more than ~50IBU I get an increase of the 'grassy' tasting hops that you describe.

I don't know if that is the case here, but to me it comes off as too harsh and vegetal when I hop at that level in low OG beers.

 

[robdoerk]

I recently had a similar problem. I had never had a grassy taste in my beers either, but 3 brewdays ago, an ESB came out with a decidedly annoying grassy flavour. I thought at the time that it was probably bad hops. But then on the subsequent brewday, after everything had seemed to go well through the mash and boil stages, as I was cleaning the boil kettle, the same grassy aroma was present. I smelled the chilled beer and it had a strong grassy smell (which I hadn't smelled earlier in the brewing process). I sometimes brew two batches in a brewday, so in the 2nd batch of the day, I kept monitoring for the grassy smell, but it wasn't there ... UNTIL ... I chilled the boiled wort through my plate chiller. Immediately upon chilling the wort, the smell was immediately present. That's when I realized that the smell (and flavour) was coming from the chiller itself. I am usually pretty good at cleaning all my equipment, but I'm guessing I forgot to clean the plate chiller 4 brewdays ago, and that an infection set into the chiller. I ended up disposing of 3 full batches of beer (all were essentially undrinkable) and also the Plate Chiller. I bought a new Plate Chiller and on my most recent brewday, I brewed two successful beers without any grassy smell/flavour. Any chance you have some infected equipment?

 

[Stillraining]

I recently had a similar problem. I had never had a grassy taste in my beers either, but 3 brewdays ago, an ESB came out with a decidedly annoying grassy flavour. I thought at the time that it was probably bad hops. But then on the subsequent brewday, after everything had seemed to go well through the mash and boil stages, as I was cleaning the boil kettle, the same grassy aroma was present. I smelled the chilled beer and it had a strong grassy smell (which I hadn't smelled earlier in the brewing process). I sometimes brew two batches in a brewday, so in the 2nd batch of the day, I kept monitoring for the grassy smell, but it wasn't there ... UNTIL ... I chilled the boiled wort through my plate chiller. Immediately upon chilling the wort, the smell was immediately present. That's when I realized that the smell (and flavour) was coming from the chiller itself. I am usually pretty good at cleaning all my equipment, but I'm guessing I forgot to clean the plate chiller 4 brewdays ago, and that an infection set into the chiller. I ended up disposing of 3 full batches of beer (all were essentially undrinkable) and also the Plate Chiller. I bought a new Plate Chiller and on my most recent brewday, I brewed two successful beers without any grassy smell/flavour. Any chance you have some infected equipment?

Great first post.. robdoerk and you have been around a while, what gives?

 

[soccerdad]

Thanks everyone for chiming in. Helps me narrow things down and gives me some good ideas on what to adjust.