Pale Beers = Vegetal Flavours From Hop Breakdown Or Dms?

[argon]

The last 2 pale beers (say 7srm or less) I’ve done have had some pretty weird off flavours… I think “vegetal” not sure about how this has occurred. Not grassy definitely a cooked vegetable flavour, rounded, not sharp and grassy.

Been reading a bit about 2 possible causes:
1. Leaving hops in the fermenter throughout fermentation
2. DMS production from Lightly kilned malts and No chill

Firstly, the leaving of hops in the fermenter issue. I’ve done this a number of times, both with Pale (7srm) beers and others (say 12srm and over). I NC cube hop most beers. I always just chuck all the contents of the cube in the fermenter onto a healthy starter. The only times I’ve had off flavours is as above…ie if I’ve been using a high % of lightly kilned malts such as pilsner or pale malt, resulting in light coloured beers.

This brings me to issue no. 2…DMS production. Some of the reading I’ve been doing leads me to consider that paler malts, pilsner malt specifically leads to higher levels of DMS. Now… I tend to boil for 75 – 90 mins in attempts to drive the precursors of DMS off. However something is still going wrong. My fermentations always kick off pretty quickly, so any more DMS left should (theoretically) also get driven off by a health robust fermentation.

If I’ve always done the cube hop thing with light, medium and dark beers. So if I’m only picking up off flavours in the light beers, then there is 2 possibilities;
1. the off flavours are being masked by the darker beers, or;
2. the malt profile of the lighter malts puls the no chilling is creating DMS (I think) or some other cause of the Vegetal flavour.

The latest “Vegetal” beer was Tony’s Bright Ale which through my system was done with 68.75% Weyermann Pilsner came out at 3.8 SRM or 7.6EBC. Only been in the keg a week… hoping it will mellow out in time with a bit of lagering.

Anybody else experience this?… or any suggestions as to what’s going on?

 

[benno1973]

I've dry hopped before using a hop tea (with some old-ish Cascade hop plugs) and ended up with a horrible vegetal flavour. How fresh are your hops? Do you ever dry hop?

 

[Fourstar]

cooked veggies (i assoiciate it with steamed greens or cabbage, others say creamed corn) is DMS.

The lighter the malt, the more SMM pre-cursor there is in the malt. Just the nature of the game. Try using another supplier of pilsner malt JW for example as your next light beer, see if it makes a difference as their may be lower amounts of SMM in their barley.

Also, make sure you have a good rolling boil to try and drive off as much DMS as possible. It is recommended to rapidly chill beers to reduce DMS, although i havnt noticed any negative effects using domestic malt (JW) for my pilsners or other light coloured beers. Heck just for a change, i use Pils as my base malt in ales if its the base malt i have closest at hand.

I'd look at ensuring you have a good rolling boil (kettle uncovered) first before looking at other issues.

 

[benno1973]

Quick cooling is recommended (as fourstar said) so that's going to be difficult if you NC. I've heard people say they use JW over Weyermann when no chilling to reduce DMS.

 

[Fourstar]

Quick cooling is recommended (as fourstar said) so that's going to be difficult if you NC. I've heard people say they use JW over Weyermann when no chilling to reduce DMS.

its also noted using undermodified malt can help, the undermodification reduces the production of SMM during the germination period which might also help if you can get your hands on some.

Personally i just give the local malts a crack, :icon_cheers: Or cut your malt with some local malt to reduce the % of SMM precursor.

e.g.
50% Weyermann Pils
50% JW Pils

 

[mxd]

I, do NC too.

I've had a flavour that I refer to a veg, but I assumed it was a yeast issue ? When I taste the cold (room temp) wort I don't taste it but after a week in the fermenter it's there, the last one I had 4* taste, I am not too sure if my version of a veg flavour is the same as yours ?

I must also google for DMS

 

[jayse]

You would have tasted DMS before in many beers so when you say its a 'pretty weird off flavour' it almost suggest something else.
Wild yeast/bacterial infection can produce sulfer compounds with are much more unpleasant cooked vegetable flavour then DMS.

 

[argon]

So current consensus is DMS... oh well.. nothing like 38L of cooked veggies. Was supposed to be a couple of easy drinking kegs for a party in 2 weeks... not happy. Will DMS dissipate over time?

Yeah I think a more aggressive boil could possibly help... I tend to have a decent enough rolling boil though but guess it couldn't hurt to crank it up a notch. Just got to adjust for higher boil losses evap rate and the like.

My grain is always fresh as I order, have it milled and pick it up on brew day. Same with the hops, they get opened about 15mins before the boil, so no issue there.

JW malt in lieu of Weyermann... also worth a shot. I get everything from Ross, as it's a 10 min trip down the road to pick up. He doesn't stock JW Pale or Pilsner... how about Barrett Burston instead?? Would prefer to have a single supplier.

I've used the same re-cultured yeast a couple of times and never had an issue with it... haven't had an infection in a loooong time so i'd day it's the least possible option. Not to say i'm immune to infections, just that it tends only to happen in similar style beers that use alot of light malts. Fourstar's explanatio of the flavor is fairly spot on to what i'm getting.

 

[jayse]

snipped>

JW malt in lieu of Weyermann... also worth a shot. I get everything from Ross, as it's a 10 min trip down the road to pick up. He doesn't stock JW Pale or Pilsner... how about Barrett Burston instead?? Would prefer to have a single supplier

Might aswell take a beer down to the shop and get him to taste it.
Barrett Burstons is most excellent try the galaxy malt for these beers.

 

[argon]

Might aswell take a beer down to the shop and get him to taste it.
Barrett Burstons is most excellent try the galaxy malt for these beers.

Yep definitely be doing this... although it does remind me of this....

"Hey mate this beer tastes like shit... Want some?"
"Yeah i'd love to taste some shit... thanks!!"

Have heard good things about Galaxy... almost used it actually for the Bright Ale... going to use it next on a Galaxy SMASH... ie Galaxy Malt, Galaxy Hop (one addition only... Cube hopped to approx 33IBU)

 

[newguy]

As someone else mentioned, an infection can create a vegetal flavour/aroma but in my experience this isn't very long lived. It turns sour/funky in other ways pretty quickly.

That aside, your boil time is fine as long as you don't have a lid on your kettle. However, DMS is quite volatile and will be scrubbed out during fermentation as long as you've pitched enough yeast. A local micro's beers all smell like boiled peas/broccoli right into the fermenter but a day later the smell is gone. They pitch a lot of yeast.

Some hops are vegetal. Fuggle is the worst and I imagine that close Fuggle analogues like Willamette are probably similar.

 

[argon]

ok... i have to kick myself for not connecting the dots earlier... just had a read over some notes from the last few brews.... low and behold, each time i've done a batch with a high ratio of pilsner malt... guess what... Vegetables!! DMS i'm now assuming. Anytime I've used Pilsner Malt, it's always been Weyermann. Evap rate has always been consistent at approx 9%

When I said earlier that all brews under about 7SRM had turned out poor, that wasn't accurate. I did a summer ale with Maris Otter that was about 4SRM and came out beautiful. No off flavours at all. Beautifully light bodied, diamond bright and easy drinking, strong hop flavours, fruity and balanced.

So now the plan of action is... Local malt JW or most likely BB when using Pilsner. Boil hard(er) and try and chill fast... maybe that's an excuse for a plate chiller.

Who'd a thought... one particular malt could change the profile so much... notch this one down to a learning experience. Gonna be tough to choose Pilsner malt in the future, especially when i've had good experience with a pale beer using MO Ale.

 

[argon]

ahhh bollocks!!! :angry:

Latest batch of a light ale has come out with some more DMS. I thought i had this issue sorted. Did a couple of lagers late last year that was all good. Thought i'd try another blonde/pale ale nice and light for summer, but it looks as though i've turned out another cooked vege double batch.

Thankfully i still have the second half of the double still in the cube. Was thinking of boiling it again to drive off some SMM.

One thing i'll need to consider is the IBUs and hop flavours and aromas. I'll add some more late hops to the boil to adjust for that. I reckon it may be a bit hit and miss... but better than having another keg of what i currently have.

Anyone done this before or can see any other issues with boiling cubed wort?

 

[mxd]

how long are you boiling for ?

a 90 ,im boil will help drive off some dms

 

[cdbrown]

Are you doing a 90min boil for these types of brews? Everything I've read points to a good long boil for brews with pilsner malt

edit - damn you mxd

 

[argon]

Are you doing a 90min boil for these types of brews? Everything I've read points to a good long boil for brews with pilsner malt

edit - damn you mxd

Yeah i'm pretty sure that was my issue... only boiled for 60 mins. So i think i might boil the cube for another 30 at least

 

[cdbrown]

I've no idea if that would work. Is DMS produced when the wort chills or during ferment. All I know is that it's recommended a long boil to "drive off the precursors of DMS"

 

[argon]

I've no idea if that would work. Is DMS produced when the wort chills or during ferment. All I know is that it's recommended a long boil to "drive off the precursors of DMS"

A quick read of here suggests it may work. Should have read this before brewing the beer though <_<

this is slightly encouraging though;

DMS is created whenever wort is heated, by the breakdown of precursors found in pale malts. Under ordinary circumstances, most of the DMS that is created by heat is then evaporated during the boil.

 

[MHB]

Weyermann are one of the best maltsters in the world, it would take a braver man than me to lay the blame of this one on them.

Prime causes as mentioned above: -

Inferior Malt - Weyermann don't make any, whatever our differences of opinion I doubt the malt from Craft Brewer is anything other than well looked after.

Inadequate Boil all pilsner/lager malt contains sulphur compounds (yes even Australian malts) that need to be driven off in the boil, 9% evaporation should do the job, but you might want to have a look at your boil. Ale malts have the Sulphur compounds ejected during the more intensive killing they receive so that's possibly why you haven't had the same problem with Pale Ale.

Infection it's a good chance this is the culprit, the quick test is to split a brew (just a couple of litres) brew the bulk of it in your normal equipment with your house yeast, one of the samples, brew it in a soft drink bottle/demijohn or whatever with cheap dry yeast (packet of kit yeast will do), the third in a soft drink bottle/or suchlike with the house yeast.

Should tell you if your problem is in the yeast, your fermenter or with the ingredients.

MHB

 

[kevin_smevin]

I've no idea if that would work. Is DMS produced when the wort chills or during ferment. All I know is that it's recommended a long boil to "drive off the precursors of DMS"

DMS is produced at temperatures above 80 degrees from memory. At these temps, the precursor SMM is converted to DMS but the boiling of the wort will volatilize the DMS. If no chilling, your wort sits in the temp range of 80-100 degrees for a long time so the SMM continues to be converted to DMS but because your not boiling, the DMS stays in your wort. The evolution of CO2 during fermentation will eliminate some more DMS but i dont think it works as well as a vigorous boil.