Dealing with DMS

[unwrittenlaw]

Alrighty gurus,

I'm a recently converted BIABer using a custom built 50L keggle with 2200w KK element, done about 5 batches on it. Usual batches are no chill cube 21L into the primary with OGs between 1.040 - 1.060.

My 2nd last batch (#33) was a 4.5% red wheat nelson sauv experiment I did with a mate. (rehydrated MJ M20 yeast ferment at 20c) It gave off odors of sulfur/cooked vegetable towards the end of fermentation day 4ish and the flavour was muted but no sourness. Bumped temp up 2 more degrees and gave it a few days hoping that would sort it then cold crashed for a week before kegging. My mate has been drinking it at his place and it appears the fault has scrubbed off a bit and the odour is not as noticeable and it's still drinkable but not great. My initial thoughts were yeast related (never used m20 before). My mate initially thought it's hop related (nelson probably not great as a single hop - lesson learnt).


Anyway latest batch was kegged and bottled yesterday, a porter. OG1.055 FG1.013 2pks of rehydrated nottingham at 18deg.

Taste wasn't there and the off odour the same as the batch before but not as much. First thoughts were possibly infection carry over thru my plastic carboy. I'm very prudent with cleaning and sanitation (sodium perc & no rinse starsan).

Anyway been doing a bit of reading and have come to the conclusion it's DMS. My keggle doesn't do a rigorous boil and sits around 96-98deg. Boil times are 60mins with 20 min whirlpool before transfer to cube at around 87deg.

Possible solutions are:

- 90 min boils
- Smaller batch size (16L cube) to get a rigorous boil
- Added element or over the side element

I'm thinking of asking my mate to put my next batch thru his grainfather and ferment in my carboy to see if it's hot side related?

Any thoughts to assure it's DMS and not infection (I've read some infections can give of DMS odours too) Am I missing something else?

What is the best way around these problems, fix what you think is the problem first, and change things 1 by 1 or change alot things like new fermenter, airlock etc all at once to make sure?

Input much appreciated

Cheers

 

[Jack of all biers]

It does sound like you've cottoned on to the likely problem being a lack lustre boil. 90min boil is the go and you want it 100C, but if that's not possible try 120min.

What grains were you using in your grist? Predominantly pils?

I wouldn't rule out infection though and would ensure ALL equipment gets a thorough clean and sanitizer hit. Don't forget your kettle tap/valve as they are often overlooked and gather crud that's a great breeding ground for bacteria.

EDIT - are you leaving the lid on your kettle during the boil due to it being low temp?

 

[MHB]

Sounds like you have your head around most of the possible problems and solutions.
Just a couple of points that might help: -
You want 10% evaporation, if that takes 60 or 120 minutes you still want 10%, some insulation around the pot well speed up evaporation.
Make sure the lid is off (given you have one) the kettle DMS can condense and drip back into the kettle if you have a lid on.
If you use Ale rather than Pilsner/Pale malt you will be starting with less of the SMM precursor for DMS.
Long whirlpool stands can increase the amount of DMS, as any residual SMM is still converting to DMS but the DMS isn't being stripped by boiling.

Infections that make DMS aren't all that common, assuming you keg, one place they do turn up is in the line to the tap/gun. It might be worth replacing your lines and with a good quality duel layer line (nylon/polly), not that cheap crap some suppliers sell.
A major blitzkrieg clean/sterilise of all your plastic is always a good idea. I would use something other than my normal cleaner/sanitiser try Pink (Chlorinated Tri-Sodium Phosphate, Iodophor...) disassemble everything (I usually replace plastic taps) and soak overnight in strong cleaner/sanitiser, Clean again before using.
Mark

Edit
JOAB said most of the same things, just shorter (succinct) - all good.
M

 

[Jack of all biers]

Yes, but I like your use of blitzkrieg! A word not used often enough in the beer world

 

[MHB]

It's probably Reinheitsgebot!
Mark

 

[TwoCrows]

I am using the same kettle setup as you unwrittenlaw .
I have found that placing a large hand towel folded under the kettle to fill the void and allowing the kettle to sit as it should. Then wrapping a few heavy beach towels around the kettle, leaving the heater element uncovered so not to over heat the unit.
I have experienced great boil off 31- 26 litres over an hour boil. Good rolling boil disturbing about half the surface area.

 

[unwrittenlaw]

Thanks for the help and quick responses.

The second last batch was 45% pils.

I will pull apart the 2pce ball valve and give it a thorough clean and sanitise as I just flush it a few times with boiling water & sodium perc when cleaning up.

Lid is left off during the ramp up and boil.

After the first run of the keggle I was disappointed in the vigor of the boil and got some clark rubber foil foam insulation that seemed to help a bit.

My keg lines are valpar flexmaster II and about 9 months old.

Will go blitzkrieg with another cleaning agent to ensure cold side is covered.

Interesting comment there 2crows. I use the the keggle on 2 saw horses so there is probably alot of heat loss thru the bottom. I will put a sheet of ply under with a folded up towel in the void. Could be a cheap and effective upgrade.

 

[manticle]

If caused by infection, the flavour will likely increase until it's unbearable.
If you are kegging and it's just residual, you can degas and regas a couple of times to reduce it.

Boils are really important - try and increase your heat, definitely lengthen. Thirsty Boy recommended floating an aluminium takeaway container on the surface to increase boil vigour - sounds odd but if I trust any brewer, it's him (sadly missed).

 

[unwrittenlaw]

So I filled the keggle up with 28L water (preboil volume) to see if putting a board underneath with a towel would help. Couldn't get it passed 96deg. The current element isn't cutting the mustard.

I'm on the hunt for an over the side immersion element. I found this one on eBay for around $70+ delivery. These appear the same brand that are for sale with hayman electrical. (Stoke)

Any thoughts or recommendations?

I have been purging the keg daily and still getting the off smell. I haven't tapped the keg yet, waiting for a tap to be free.

 

[MHB]

Might be a good idea to test the resistance on your element, some cheap elements can be a fair way off their stated value (i.e. 1800W rather than 2200 is says)
Mark

 

[manticle]

If you can get a Grimwood for a good price, go for that. I have bought cheap imitations before- the money saved gets spent later.

Not a comment on that specific brand.

 

[unwritten law]

Any chance of getting my old profile back?