bja

Recipes 

In this case the "grassy, vegetal flavor" is specific to the type of hops used, not from dry hopping for too long.

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WhiteDog87

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So here is my 2cents FROM PERSONAL EXPERIENCE.

I made 10gallons of a hoppy west coast red. The first 5gallons I dry hopped with 1oz Cascade 1oz Citra and bottled 10 days after dry hopping. The second 5gallons I dry hopped the same way, but I didnt get around to racking off the hops for about 3 weeks.

The first 5gallons was great. The second 5 was NOT. The second batch that sat on the hops for 3 weeks tasted grassy (not in a fresh hoppy good way, but in an astringent bad way) and had a flavor and aroma that reminded me of a mulch pile or the smell that comes out of a trashcan with yard trimmings in it.

I think those of you who are dry hopping in the keg have the benefit of preservation from the cold temps inside your fridge, which probably keep the hops from imparting these flavors.

duboman

Recipes 

Pretty poor reasoning as some of these same hops were used for shorter periods of time with no ill effects resulting

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iBrewR

Recipes 

And what are the specific hops that have grassy, vegetal flavor?

bja

Recipes 

Good question because I guess I've never used those ones.

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bobbrews

Recipes 

I've brewed hundreds of dryhopped American IPAs and IIPAs. The longest period I dryhopped was only 14 days. I usually hover around a median of 8-12 days, and found no benefit of a lesser 3-5 day dryhop by comparison. I have used both pellets and leaf hops. Dryhop temps. are typically 64-72 F. I've done it in both the primary and secondary. And I have never experienced a grassy, vegetal, green character from these beers.

With that said, I tend to primarily use American, high alpha, Pacific Northwest hops like Citra, Amarillo, Simcoe, Centennial, Chinook, Horizon, Columbus, Apollo, Nugget, Summit, etc. - These beers are always either quite fruity, citrusy, tropical, dank, resiny, floral, or all/some of the above.

However, perhaps you could get some of that vegetalness by dryhopping for an extended period with a hop that isn't necessarily great for dryhopping with like Perle, Magnum, or any of the other Noble, European varietals. I never bother with these hops late in the boil for my IPAs.

usfmikeb

Recipes 

I've never dry hopped for more than 14 days, so I haven't had grassy flavors in my brew from dry hopping too long. However, I've tasted beers in homebrew clubs where a grassy flavor is noticable, and those beers have typically been dry hopped for a longer period of time. This is my experience, so I've seen grassy flavors come out of dry hopping too long (of which 8 days shouldn't be an issue).

I have HEARD that dry hopping in your keg reduces the likelihood of grassy flavors because of the cold temperature, but I haven't tried it yet.

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Primary: Apfelwein 6/12, Peach Pyment 2/12, Cherry Melomel 9/12
Secondary: Douglah Capsicumel 10/11, Chocolate Mead 10/11, Bochet Mead 11/11, Cranberry Mead 11/11, Elderbarrel Flanders Kriek 9/12, Skeeter Pee 6/12
Bottle Conditioning: Spiced Mead 5/11, Peach Mango Mead 7/11, Spiced Cherry Dubbel 8/11
Kegged: English Barleywine 11/11, Chocolate Stout 2/12, Apfelwein 2/12
On Tap: Porter 10/12, Cherry Dubbel 9/12, Yooper's Pale Ale 11/12
Gallons in 2012: 88

duboman

Recipes 

Honestly can't answer the question as to what hops were used. It's just something I experienced in tastings of others beers in club meetings and such where extended periods of dry hopping was done. As I previously stated I'm one to go 5-7 days and very rarely have pushed 10.

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bobbrews

Recipes 

For those of you who have AND have never experienced big grassy flavors (supposedly from an extended dryhop):

*How long are these beers fermenting AND conditioning prior to adding the dryhops?

*What specific hops are you using in the boil and the dryhop?

*Roughly how many total IBUs Tinseth do these beers contain?

*How much total kettle hops are you using (minus the dryhops) per 5 gallon batch?

*How old are the dryhops?

*What ratio of dryhops per oz. / per gallon of beer are you adding?

*Are you careful to avoid oxygenation when adding your dryhops?

*What temp. do you dryhop at?

*Are you heavy handed on your 90/60/45/30 minute additions? And light handed on your 15/10/5/0/DH additions?

*Do you experience grassiness after hopbursting with a ton of late boil hop additions in addition to a substantial, extended dryhop?

...Let's eliminate these factors before we jump the gun on what we think the cause may be. It could be a combination of these things and may or may not have nothing/something to do with dryhop length. If enough people answer, maybe we can find a pattern so we can understand why some people experience grassy, and why others do not.

WhiteDog87

Recipes 

From my example above:

1. Fermented for about 10 days and then dry hopped
2. Cascade/Citra
3. 2oz for 5 gallons
4. IBU's I dont remember, typical IPA
5. Fresh, couple of months old?
6. Only have had the grassiness that one time