Possible Causes of Asparagus/Vegetal flavor and aroma

[robgoodwin]

I just got my score sheets back from a small club competition and all the judges commented on the strong asparagus taste/smell. I’m not sure what I am more concerned about, the asparagus, or my palette not picking it up. I’m pretty anal about sanitization and feel like I have a decent process, although there is always room for improvement. The second beer I entered took first in its category.

What are causes of the asparagus flavor/aroma? The beer was an all grain Northern English Brown from the Brewing Classic Styles book. Fermentation was kept at 67 degrees. Oxygenated using one of the aquarium pumps with the air filter. Kegged and filled a couple bottles a few days before the entries where due. Looking for suggestions of where I might have gone awry so I can hope to eliminate that flaw in future brews.

 

[pointcity-homebrew]

I have read somewhere that DMS (Dimethyl Sulfides) can produce an overcooked asparagus flavor. Never experienced it but do remember reading it somewhere around the web.

I also remember it pointing to a problem during the boil. I will post the source if I can find it again.

Ok found the source.

http://www.lewybrewing.com/p/beer-off-flavors.html

 

[unionrdr]

Check this out from Palmer's book under DMS; http://www.howtobrew.com/section4/chapter21-2.html

 

[TheCanisDirus]

Came here to say DMS... but, yup.

 

[robgoodwin]

Thanks for all of the replies. What is funny is that the sheets where very detailed, but did not mention DMS. The Vegetal checkboxes were marked on the scoresheets, but not the DMS. Which made me think this was something other than DMS.

 

[fearwig]

Yeah, I think they would have said DMS if they meant DMS. Vegetal is a common descriptor for a hop flavor you get from a large bittering addition and/or a long boil--and I mean large in terms of volume, not IBU, so we're talking several oz of low AA, maybe a 90 minute boil. It's a reason some big commercial DIPA makers turn to hop extracts for their AA. Does this jibe with your recipe at all? It doesn't sound like it should, unless you had a crazy low AA supply and had to compensate.

DMS does not seem too likely since I doubt you used a super light base malt, unless you had a real boil problem. It would make sense with "asparagus", though people usually say "canned corn". Maybe one judge got the idea in his head and tainted the others?

 

[robgoodwin]

No, I used pellet hops and not so much as to get an off flavor from it I believe. I guess I will sanitize like crazy and try again. Thanks so much for all of the input.

 

[flars]

No, I used pellet hops and not so much as to get an off flavor from it I believe. I guess I will sanitize like crazy and try again. Thanks so much for all of the input.

Doesn't sound like a sanitation problem. I would look at the yeast used, wort temperature and the optimal temp range for the yeast, and pitch rate.

How long did you condition the beer before bottling?

 

[robgoodwin]

I used WLP013. I did not make a starter, but pitched 2 vials into 5.5 gallons of wort. I had it sitting in a compartment constructed around a dorm fridge with a controller set to 66.

 

[TobyG]

Thanks for all of the replies. What is funny is that the sheets where very detailed, but did not mention DMS. The Vegetal checkboxes were marked on the scoresheets, but not the DMS. Which made me think this was something other than DMS.

Most judges will only associate DMS with cooked corn. So if they get a vegetal smell, they're not going to always call it out as DMS.

 

[unionrdr]

I've never experienced or heard of that sort of flavor from yeast esters or phenols. But maybe combined with old hops?...

 

[QuercusMax]

What hops did you use? I found a thread below (https://www.homebrewtalk.com/f37/vegetal-celery-flavor-esb-183371/) that blamed asparagus/celery flavors on using lots of Fuggles.

 

[TobyG]

From the BJCP Faults document: "Encourage a fast, vigorous fermentation (use a healthy, active starter to reduce lag time; this is often due to bacterial contamination of wort before yeast becomes established). Check sanitation. Check for aged, stale, or old ingredients (especially old liquid malt extract). Avoid oversparging at low temperatures."

http://www.bjcp.org/docs/Beer_faults.pdf

 

[TobyG]

What hops did you use? I found a thread below (https://www.homebrewtalk.com/f37/vegetal-celery-flavor-esb-183371/) that blamed asparagus/celery flavors on using lots of Fuggles.

A high volume of poorly stored hop matter can lead to a musty, vegetal aroma.

 

[fearwig]

What would "oversparging at low temperatures" mean? What would that extract that 170F sparge water wouldn't?

The vegetal=bacterial bit makes sense, actually, that's much the smell you get from bottled water when it goes bacterial.

 

[robgoodwin]

The wort cooled to about 80 pretty quick via my immersion chiller, but I did let it sit for about 6 hours in the fermentation fridge to get down to 65 before pitching. I did use one of the aquarium pumps with the sterile filter. Perhaps the filter is bad? Wonder if I got something there. I used EKG as the hops and fermentation started within hours of pitching.

 

[fearwig]

If the filter is tainted, maybe you have something--but if it's just failing to filter that really shouldn't be an issue (again with what I always say about most infections not being airborne).

 

[TobyG]

What would "oversparging at low temperatures" mean? What would that extract that 170F sparge water wouldn't?

Good question. Not sure why the temperature would make that big a difference as opposed to just not oversparging in general.

 

[cjgenever]

We need a recipe and details of your process to really help.