Sulphurous Smell in Pale Ale

[TheSumOfAllBeers]

A light pale ale I have has a noticeable sulphurous smell on the nose. I think it would dissipate fairly quickly in an open glass (will test later), but I am keen to get to the bottom of what is causing it, as it is not the first brew where this has come through.

There was no sulphur in the flavour.

Some details of the beer:
Its a low gravity light ale,
- %80 Maris Otter, 20% Various wheats (malt, flaked & torrified)
- A decent chunk of Pacific Gem from the group buy, all added late (15m, and at 0m into a plastic cube for no chill - i.e. the wort cooled down overnight)
- US-05

Some opinions that I heard might cause this:
- a side effect of autolysis, where the cleaned up sulphurous compounds were released as dead yeast was destroyed
- however there was no obvious autolysis present
- an infection

Other details that I can recall
- the beer stayed in primary for an extended period - about 7 weeks over the xmas period
- it fermented cool, but there was NO temperature control
- ambient temps in the kitchen would have fluctuated from about 8-10C -> 18C (house empty until we are back in the evening)
- I can't recall how vigourous the boil was, but it was no longer that 60m, but the mash would have been around 90m including mash out
- fermentation was otherwise pretty solid

If anyone can suggest other things that I could look into and investigate, I would appreciate it. Everything else about this process was really good, and its getting my beer into the ballpark of where I want them to be.

[Tom]

Sometimes the yeast is just a bollix and will produce sulpher, and did you treat your water with any salts?

[Dr Jacoby]

Certain yeast strains produce sulphurous gases during fermentation, especially lager yeasts. These gases normally dissipate towards the end of fermentation and during the lagering. In ales, certain English yeast strains are known to produce sulphur-like flavours and aromas (especially in burton style beers). There's some good info here:

http://www.winning-homebrew.com/sulfur-odors.html

[Will_D]

Good link but to be clear, there are 2 sorts of "sulphur" odours:

Hydrogen Sulphide (H2S) - rotten eggs caused by degrading sulphur in certain proteins

Sulphite ( SO3 is the disolved ion of Sulphur Dioxide SO2  ) like from campden tabs. This is  a sharp acid smell quite different to the H2S and is in all probability comming from the yeast. Unless you have a major input of Sodium/pot. meta-bisulphie to your beers (like incorrect rinsing of the sulphites)

[DEMPSEY]

I think Will-D is on the right track. How are cleaning your gear and are you using cambden tablets in you water treatment.

[TheSumOfAllBeers]

1 camden tablet was used in the water treatment.

The yeast was US-05, which I would not normally expect to introduce strange fermentation character.

Thanks guys, you are giving me a lot of good leads to research.

Also, this beer is getting a bit of inter-bottle variation.

[johnrm]

Re: bottle variations...
Did you bottle from primary?
Batch prime?
If Carb drops, was yeast settled when bottling?
How is your bottle sanitation?

[sub82]

I have had sulphur smells in 1 or 2 batches and suspected it was due to under pitching. The starters smelt ok but then when I pitched, 24 hours later it was an egg bomb!

[TheSumOfAllBeers]

Re: bottle variations...
Did you bottle from primary?

In this case yes I did

Batch prime?

No, not this time. I made up a sugar solution and dropped 5ml at a time into each bottle, and bottled straight on top of it form primary.

If Carb drops, was yeast settled when bottling?

No carb drops, but there was a slight yeast haze. This was US-05, which can take its time, but it was 7 weeks in the primary, and i didn't want it there any longer. (I hate how christmas makes a mess of my brewing schedule)

How is your bottle sanitation?

Worth looking into. I normally rinse all bottles on a bottling tree with bleach/vinegar no-rinse sanitiser, and then cap them with plastic reseals (which are also sanitised in same solution). Odd smell from some bottles, which I didn't use. Been waiting for a delivery of star san from the guy at the home brew club.

Lastly, the inter-bottle variation is especially pronounced when the beer is shook up. Beer that got shook up on the way to club tastings/work tasted a bit off compared with bottles brought down from the attic.

[TheSumOfAllBeers]

I have had sulphur smells in 1 or 2 batches and suspected it was due to under pitching. The starters smelt ok but then when I pitched, 24 hours later it was an egg bomb!

In my case, US-05 was hydrated in boiled, then cooled water. Wort was around 1.043 22L batch.

[Ciderhead]

I would look at some kind of fermentation temp control as yes 05 will perform at all sorts of temps but it doesn't mean it won't influence final product, and I would also consider a new bucket.