Bottles Are Superb, Keg Sux!

[colinw]

All,

I have a baffling problem with a batch I kegged and bottled about a month ago. It was a fairly standard example of one of my English pale ales - pale malt, crystal malt, chocolate malt, flaked maize infusion mashed at about 67 degrees C. Target, Northdown & Goldings hops to around 35 IBUs in a 1.049 OG beer. Fermented with Nottingham ale yeast at about 18 degrees C.

The fermentation proceeded smoothly, attenuating quite well as Nottingham always does. I kegged a single corney keg plus 8 or so XXXX tallies and some Corona stubbies. Priming of the bottles was minimal, for low carbonation.

Now, to the problem. The bottled version of this beer is superb - when served at 12C it tastes very close to some cask ales I've had in the UK. The Target hops, used for bittering, have come through strongly in the flavour as a kind of bitter marmalade flavour.

But, the keg really stinks - literally!. It has developed a sulphury aroma. Once the sulphur dissipates the beer is quite similar to the bottled version, but the sulphur is very distracting and you have to stand the glass for about 5 minutes before drinking it. I know sulphur is an integral part of the profile for some ales (Bass for example), but I don't like it and I don't understand why my keg has developed sulphur yet the bottles are completely free of it.

The keg was artificially carbonated and put in the fridge immediately, which I would think would minimise the chance of infection. The cleaning regime for the kegs is a wash with detergent and hot water, then a purge with dilute iodophor which is pumped out through the beer line and tap.

Could I be dealing with some kind of low temperature infection - some bacteria (Pediococcus species) will produce sulphur? Or alternatively, autolysis of the small amount of yeast which made its way into the keg (but why didn't the yeast in the bottles autolyse)?

The funny thing is once the sulphur dissipates the beer is damn near the same as the bottled version.

I'm baffled. Usually my kegged and bottled beers are close to identical, bar a slightly drier finish on the bottles due to the priming sugar.

cheers,
Colin

 

[big d]

beats me colin.perhaps a bit of secondary fermentation in the keg is producing the smell.
have you thought about opening your relief v/v leaving overnight then gas carbing the next day to see if this removes the odour.?
im curious about this one as ive never come across it and your sanitation appears normal.

cheers
big d

 

[colinw]

Got me beat. I did nothing different to the 20 or so previous kegs since I started kegging at the start of 2003. I've never had even a hint of a sanitation problem with my kegs, or any "slimies" in my taps. This keg was rotated from a batch which blew dry the night before I kegged - so it was literally a case of take empty out of fridge, clean it with detergent, rinse it, put iodophor in it, stand it, pump iodophor out through the beer line & tap, then bottle & keg. Same process I always do.

I can only figure I either got a wierd one off infection, somehow managed to induce yeast autolysis, or am getting a continued slow fermentation from stressed out yeast as you suggest. Nottingham is capable of working slowly down into lager temperatures, so maybe there's some feeble activity which is giving off sulphur.

 

[Snow]

Infections aside, does yeast clean up sulphur? If it does, maybe the problem is the yeast activity during secondary fermentation in the bottles is cleaning up the sulphur, but the clean-up process is a lot slower (or halted comepletely) in the keg because it is chilled? If this is the case, it would be a simple problem of taking the keg out of the fridge and storing at room temp for 2 weeks. I would de-gas it first, as the yeast work better with less co2, and they'll be producing it themselves.

or....I could be wrong!

Cheers - Snow

 

[shwab]

Stinks with a sulphury aroma? Do you mean hydrogen sulphides, commonly reffered to as a rotten egg smell?
If that's the case it can be very easily fixed by the addition of a small amount of copper sulphate. The copper bonds with the sulphides forming insoluble copper sulphide and drops out of the solution, the sulphate ions form a minute amount of sulphuric acid.
A small pinch should solve the problem almost instantaneously and is one of the easiest problems in a beer to fix.
Of course if it was in bottles you'd be screwed

What i mean to say is that sulphur itself does not smell like rotten eggs, and it can form many compounds in beer that have nothing in common with the smell. The smell is from hydrogen sulphides (H2S) and is easily fixed.

 

[Darren]

Rotten egg smell will fade with age. Its a good idea to "purge" the kegs to help get it out of there. My guess is, As the last glass is being consumed there will be little or no sulphur.

 

[Darren]

All,

I have a baffling problem with a batch I kegged and bottled about a month ago. It was a fairly standard example of one of my English pale ales - pale malt, crystal malt, chocolate malt, flaked maize infusion mashed at about 67 degrees C. Target, Northdown & Goldings hops to around 35 IBUs in a 1.049 OG beer. Fermented with Nottingham ale yeast at about 18 degrees C.

The fermentation proceeded smoothly, attenuating quite well as Nottingham always does. I kegged a single corney keg plus 8 or so XXXX tallies and some Corona stubbies. Priming of the bottles was minimal, for low carbonation.

Now, to the problem. The bottled version of this beer is superb - when served at 12C it tastes very close to some cask ales I've had in the UK. The Target hops, used for bittering, have come through strongly in the flavour as a kind of bitter marmalade flavour.

But, the keg really stinks - literally!. It has developed a sulphury aroma. Once the sulphur dissipates the beer is quite similar to the bottled version, but the sulphur is very distracting and you have to stand the glass for about 5 minutes before drinking it. I know sulphur is an integral part of the profile for some ales (Bass for example), but I don't like it and I don't understand why my keg has developed sulphur yet the bottles are completely free of it.

The keg was artificially carbonated and put in the fridge immediately, which I would think would minimise the chance of infection.


Darren wrote:
The yeast in the keg at this time would have removed the sulphur if you left it for a day or two before refrigerating. Also, Infection in the beer will most likely to have occured before the stage of kegging.




Colin:
Could I be dealing with some kind of low temperature infection - some bacteria (Pediococcus species) will produce sulphur? Or alternatively, autolysis of the small amount of yeast which made its way into the keg (but why didn't the yeast in the bottles autolyse)?


Darren
Certainly not autolysis in the given time. Probably not an infection in that time-frame with fermented beer either. It is more likely the beer in the keg fermented at lager temps for quite a few days (hence the sulphur). The beer that was bottled also became better airated at bottling. Gave the bottled yeasties the required oxygen to clear up the sulphur.
cheers


cheers,
Colin

[post="99228"][/post]​

 

[warrenlw63]

Don't knock it Colin.

Nothing wrong with a bit of authentic Burton (snatch) aroma. :beerbang:

Just out of curiousity Colin. Your beer isn't warming up in the lines is it?

Warren -

 

[sosman]

I can dispose of those nasty kegs for you.

 

[Sean]

Burton snatch (sulphours smells) are controlled by in cask beers (especially Marston's Pedigree) by extensive venting. Leave the vent open overnight (or longer if necessary) and then re-carbonate. It's all quite normal in cask conditioned beers - which require venting precisely to deal with unwanted or excessive volatile aromas.

 

[colinw]

Thanks all for the replies. Been off net for a while because my computer decided to s**t itself. Running on a hastily installed P-II 300Mhz "clunker" for the time being.

The sulphury keg has been vented and recarbonated, and is now palatable but a little bit sulphury. Warren's description of it being "Burton snatch" is probably about right in its present state, before it was just too much.

I suspect the hypothesis about fermentation at lager temperature (keg) vs. slight aeration and more vigorous warm fermentation in the bottles is on the money.

I can pour a glass and the slight sulphur dissipates within a minute or two, leaving me with a beer which is rather close to draught Bass in character.

cheers,
Colin

 

[colinw]

Guys,

A few weeks ago ago I bitched about a batch of English Pale Ale where the bottles were superb but the keg was sulphury. That keg eventually came good with ageing and ended up a quite close replica of draught Bass.

Well - I've done it again. I have another batch where the bottles are much better than the kegs.

This time it is the English Brown Ale. Fairly normal recipe with Maris Otter, crystal, chocolate malt, black malt and flaked maize. Goldings & Northdown hops. Used Safale S-04, for no particular reason except to get rid of a sachet that's been hanging around (but was still within use-by).

The ferment was uneventful, perhaps rising a tad too warm (22C) at one point, as my temperature controller seems to be on the way out and has developed about a 6C bias (ie. have to set it to 12C to get 18C). OG was 1.047 for FG of about 1.012. At bottling/kegging everything tasted normal.

Fast foward a couple of weeks. The kegged beer has a slightly annoying solventy ester or fusel in it. When poured cold it comes through as an unpleasant "bite" in the beer. As the beer warms up it becomes obvious as a slightly solvent-like aroma, which then clears and leaves a good beer. The off flavour is clearly related to the "strawberry ester" ethyl acetate, and once it clears the beer has a distinctive estery flavour.

Last night I cracked a bottle of the same beer. Absolutely no sign of that off flavour - it was a classic example of an English Brown and much nicer than Newcastle Brown in my opinion. Crystal clear as well. The bottled beer is nice and estery with a bit of the same strawberrry character, but without the solvent overtones.

So - what's going on? Am I getting into trouble with a keg or beer-line infection? Or possibly something nasty in my regulator (I have had beer in the gas line once or twice). Or should I be priming & warm conditioning my English Ale kegs?

Interestingly, both batches which did this were ones I've made in the same fermenter. It is a different keg, beer line and tap however.

This is getting annoying - usually my kegged beers are as good or better than the bottles.

cheers,
Colin

 

[warrenlw63]

G'day Colin.

Could it possibly be the further refermentation in the bottle cleaning up some fermentation mistakes? :unsure:

Maybe the answer's as simple as priming the kegs for some English beers to encourage some refermentation. I do this just for grins and some scant authenticity more than anything. Can't verify if the beer's any better than force-carbed kegs or not though. Being a double batcher I must do a keg of each one day.

Hope this helps.

Warren -

 

[Tseay]

Hi Colin,

Does the following describe what you are getting :

SOLVENTLIKE
CHARACTERISTICS: An acetone-like, laquer-thinner-like, pungent, acrid aroma which is followed up by a harsh, burning sensation on the tongue and possibly the back of the throat.
CHEMISTRY: Ethyl acetate in larger quantities (>33 ppm) is the primary cause, either by wild yeast or the yeast strain used. Other compounds may also be present.
HIGH LEVELS DUE TO PROCESS: Wild yeast contamination due to poor sanitation; high fermentation temperature; non-food grade plastic equipment in contact with the beer; open fermenter, especially after high kraeusen subsides; excessive oxygenation of the wort before pitching; oxygen in secondary fermenter.
LOW LEVELS DUE TO PROCESS: Good sanitization of equipment; only food-grade plastic used; cooler fermentation temperatures; proper wort oxygenation; closed fermenter.

T

 

[colinw]

Its definitely ethyl acetate. Pitching rate was adequate, wort was very well aerated. Not a fermenter infection as the bottles are pleasantly estery but free of the defect.

I'm suspecting a temperature derived defect which cleaned up in the primed and warm conditioned bottles but not in the force carbed and chilled keg.

I'm thinking I may have a process defect in the form of kegging too soon, and should perhaps be performing a longer conditioning rest / secondary.

 

[warrenlw63]

Its definitely ethyl acetate. Pitching rate was adequate, wort was very well aerated. Not a fermenter infection as the bottles are pleasantly estery but free of the defect.

I'm suspecting a temperature derived defect which cleaned up in the primed and warm conditioned bottles but not in the force carbed and chilled keg.

I'm thinking I may have a process defect in the form of kegging too soon, and should perhaps be performing a longer conditioning rest / secondary.

[post="106095"][/post]​

Could be the case Colin.

As a rule these days I leave my kegs for 4 weeks.

Sampling/drinking them at 2 weeks isn't always a good thing. Keg leaves ordinary impressions early on, only to taste great at the 4 week point when the keg's 2/3rds empty. <_<

I've also found that no secondary and going straight to the keg from the primary successfully is yeast strain dependent. More flocculant strains (read; Wyeast 1968 and 2112) work perfectly for this, whereas less flocculant strains need the extra conditioning or possibly even a secondary fermenter and always pour ordinary for the first few pints.

Warren -

 

[AndrewQLD]

it sounds to me that your problem lies in your kegs or keg setup, if there is no indication that your bottled beer is off then it has to be either in your kegs, grommets seals ect or your tap and line or your regulator, especially if you have had beer in it at some stage. Bite the bullet and get some line and tap cleaner, soak all kegs and clean popets and seals and soak lines and taps as well and then flush.
Can't tell you how to clean your regulator though, hopefully someone else on the board can help.
I had a beer that poured from keg with similar results to you, but when I changed over to another tap the problem was solved, so I new my infection was in the line or tap.

Cheers
Andrew

 

[colinw]

I don't believe the beer ever actually reached the regulator, but can't be 100% certain.

I had a little bit of beer, and also some mead, blow back into the first half of the gas lines.

Keg cleaning and sanitisation consists of warm water and detergent, followed by a cold water rinse, followed by a normal strength iodophor solution which gets pumped out through the beer line and tap.

The taps and beer lines also get run through with chlorinated tri-sodium phosphate sanitiser periodically.

The yeast strain was plain old S-04, which is super flocculant.

I'll try pouring a beer through a nearly new picnic tap and line which I know is clean.

cheers,
Colin

 

[Tony]

Hi collin

Just a quick one

I had problems with a funny "dirty smell" in the keg beer

I was using an old second hand regulator i got off ebay cheap.

I had the same strange smell in 3 consecutive batches.

I swapped the regulator for another one and problem solved.

worth a check i recon.

cheers

 

[colinw]

Regulator was bought new - only question is whether I've actually put beer into it!

I've only had two batches out of many affected by this - have other batches on tap which are fine.