Sulfudic infection

I think this is the most useful article I have found on infections in beer.

Four batches of mine over the last 10 months have been infected with something crazy. Based on the descriptions in the article, the closest fit is that the beers have been sulfidic:

This one can smell of boiled or rotten eggs, a burning match or raw sewage.

How it is caused: Hydrogen sulfide is produced naturally by all yeast during fermentation. Lager yeasts tend to create greater sulfur aromas than ale strains. At low levels, it can impart a ‘fresh’ flavour to beers but at high concentrations it becomes an off flavour. CO2 will carry most of the hydrogen sulfide away and so conditioning or lagering after primary fermentation can ensure any left over sulfur smells or tastes fade over time.

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But I cannot work out where the problem is coming from. The first two batches that were (I think) sufludic were made consecutively and I thought it had to with sanitation - both those beers were about 5% ABV. The flavour went from bad to worse with age so i ditched both batches. I think in both batches I repitched yeast, but definitely didn't under pitch.

After that i paid extra special attention to sanitation, had a few good batches and then had it (sulfudic) again when I bottled a Westvleteren Clone. I paid extra special attention to keeping everything clean when i bottled that. I under pitched with that so thought that may be the cause of the problem. That beer came out over 10% and the last time I tasted it the off flavour had subsided a bit. So I am hoping with a bit more age it will go away.

I have just had the problem again. This time I had a split batch and used WLP 570 in one and WLP 550 in the other (fresh vials). The 550 came out fine but the 570 has this (what I think is) sulfudic flavour. I bottled this one three months ago and this sulfudic flavour seems to be getting worse.

My point is that as in at least 3/4 of the examples my experience with this off flavour doesn't fit the above description other wise that off flavour would have left the beers.

So what else can cause an off flavour that is very similar the description given above for sulfudic?

"sulfudic infection"?

Woof - sounds nasty

As WLP570 is a Belgian strain it wouldn't surprise me if it produced a fair amount of sulfur during primary fermentation.

I've often used (a likely related strain) WY3787 and it pumps out so much sulfur in the throes of primary - even with an optimal pitch and tightly-controlled wort temperature - that I'm careful to wait for the haze to dissipate before sticking my nose anywhere near the open fermentation chamber door.

It's that bad.

But ~12 days post-pitch the beer is always totally tame and the primary notes are the spicey/peppery ones that are characteristic of that yeast. The sulfur is a distant memory.

So, I'm wondering if you're giving these brews enough time pre-packaging...

Cheers!

[edit] Another thought would be pitch size. I always use starters with liquid yeast relying on the "Mr Malty" calculator to get me in the ballpark. Underpitching is notorious for causing character defects...

How long between pitching and bottling?

do you control fermentation temp?

IME the hydrogen sulfide creates a really distinct aroma during fermentation (especially with some yeast strains) but I've never had it present in the finished beer. I've not heard of any of the typical infections that cause it but I guess it's possible. It's pretty distinctive - that rotten egg/lit match thing - is that what you are getting? Something that gets worse over time does sound like an infection. The fact that you split the batch and it's only present in half goes along with something happening in the fermenter or at packaging - at least I would think eliminates a water or recipe/mash issue. And new vials would eliminate an infection from your yeast harvesting procedure (though could still be an underpitch issue). Is it mostly aroma only or also a bad taste? Is it possibly sour?

At any rate, like the others indicated some more info might help. Especially process, pitch rate, fermentation control, timeline. Recipe too just for completeness.'

Edit: one other thing. Are you fermenting in plastic? Is it possible the batches with the problems were all in the same fermenter?

chickypad said:

It's pretty distinctive - that rotten egg/lit match thing - is that what you are getting?

Is it mostly aroma only or also a bad taste? Is it possibly sour?

Edit: one other thing. Are you fermenting in plastic? Is it possible the batches with the problems were all in the same fermenter?

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Thanks for these questions.

Out of all the descriptions of infections, the description of sulfudic is the closest (if not accurate) fit. Rotten eggs more than lit match though.

I maintain temp control - within a range of about 4C - as in target temp +-2.

I ferment in plastic - but I had good batches in between the bad batches. So don't think its that.

I have repitched yeast from one (good) batch and had a good and bad batch from that same yeast...

Its not sour. its more of an aroma issue, but it does effect the taste.

In all cases it definitely has not been packaged too quickly. With my split batch I pitched in each fermenter on the same night and bottled them one night apart.

The bad beers have been two american amber ales, the Westvleteren and a Belgian IPA. All mashed as per good batches I have had and boiled for at least 60.

I hope some of you are still around. I noticed in the beers with this infection there is what looks like a powdery residue that sits at the bottom of the bottles just above the dregs. If the bottle has an indentation then that residue will sit there too.

You can see it in this picture - just above the yeast cake there looks like there is some residue. It floats/moves around when the bottle is turned around.

I noticed this is on 2 different bad beers and have never noticed it in a good beer.