Suplhur smell with US05 yeast

[Chunk]

I've just brewed a hoppy pale ale with US05 yeast. The grist was MO, Caramalt and flaked barley. The hops were fuggles, cascade, pacific gem and hallertau hersbrucker.

After 12 hours fermentation started and it smelt fine. After 48 hours fermentation was going at normal speed and it smelt fine. I've checked it this morning (60 hours in) and it really badly smells of sulphur/egg.

I know that some yeast strains do this, but I've never had it with dry US05 before.

I don't have fermentation temp control, so I've been attempting to control the temp with ice packs. As a result, it's quite possible that the temp has been up and down between the 18-25c range. Im not saying this definetly happened, its just a possibility.

What do you guys think? Combination of a malt I havent used before and the yeast? Infection? Temp changes stressing the yeast? Nothing to worry about?

Appreciate any help.

[Nyakavt]

I have gotten sulfur when the yeast is possibly underpitched or if the temperature is low. Sulfur does blow off over time, you might want to raise the temp a bit as the fermentation is finishing to let some CO2 come out of solution. Otherwise you can just wait until you don't taste it anymore.

[brewinhard]

Just give it a bit extra time before packaging it so the sulphur can outgas. If it does not outgas after an extended period of time, then you might have an infection.

[mediumsk]

I don't usually say this because it's awful advice but.... in this case...

relax don't worry, have a homebrew,

just let it condition warm for a week or two ( leave it on the yeast cake) and I'm sure it will clean up. US 05/ cal ale yeast are tard proof, small temperature fluctuations don't effect the finished beer too much as long as you pitch enough healthy yeast, however, said yeast is also a very shitty flocculator and can take a little while to attenuate fully, clean up, and drop

[Thirsty Boy]

I hate to disagree with the RDWHAHB sentiment - but as someone pointed out, US05 is basically tard proof, and one of the things it usually doesn't do is pump out sulphur.

I suspect possible nitrogen deficiency and think that next time you brew with that combination of malts etc, you might try adding some (or a little more) yeast nutrient.

If there is still some fermenttion activity... give it a little now. That way the remaining activity at least wont add to the problem.

Its also a possible infection if you have rotten egg gas... once you taste, if there is acetylaldehyde as well as H2S you might have yourself a zymomonas infection.

TB

[thatguy314]

Did you use oxygen? I've gotten some sulfer from overoxygenating with 1056. However, when the yeast dropped out of suspension they took the sulfer with it. Now I'm a little more careful about the amount of oxygen I use.

[Chunk]

I hate to disagree with the RDWHAHB sentiment - but as someone pointed out, US05 is basically tard proof, and one of the things it usually doesn't do is pump out sulphur.

I suspect possible nitrogen deficiency and think that next time you brew with that combination of malts etc, you might try adding some (or a little more) yeast nutrient.

If there is still some fermenttion activity... give it a little now. That way the remaining activity at least wont add to the problem.

Its also a possible infection if you have rotten egg gas... once you taste, if there is acetylaldehyde as well as H2S you might have yourself a zymomonas infection.

TB

My (very) limited knowledge of Zymomonas tells me that the bacteria can only consume simple sugars and not those extracted from malt? Therefore it would be very unlikely to get sulphur from zymomonas during primary. No?

I did oxygenate, yeah. Pretty heavily with an air stone and pond pump. I've done this before though with 05 and never had sulphur.

By way of an update, Im now 4.5 days into ferment, the gravity is around 1010 and the sulphur smell (although less obvious) is still present.

[ajdelange]

As has been noted here sulfidic smells are de rigueur with some strains, mostly lager strains and are considered part of what the Germans call "jungbuket" which is usually translated as "beer stench". It passes with lagering. It's removal can be accelerated to some extent by scrubbing with CO2.

The troubling thing here is that the yeast strain in question here does not seem to normally be a sulfide producer so something may be wrong or at least different. One thought is that to produce sulfide yeast need sulfate to reduce and that can come from the water or an addition of magnesium (epsom salts) or calcium (gypsum) sulfate. Were unusual amounts of those used in this brew or was a water higher in sulfate content than normal employed?