3638 Giving Off Sulphur Smell

[Dazza_devil]

Mornin Brewers,

I have a Weizenbock OG 1.073 that's into it's second day of fermentation with Wyeast 3638 and is now giving off a fair amount of SO2 smell. I've had the tempmate set at 19.5 degrees and it looked to be taking off pretty well yesterday. I pitched a 2 litre starter at 19 degrees which was meant to be at high krausen but because of cold temperatures here it was fermenting slowly. There was a lag time of 10 hours or more before I noticed visible signs of fermentation. I was expecting a huge krausen like the last time I used this yeast so I installed a blow-off tube but it's seems to have levelled off now at around two inches. I'm assuming that I have stressed the yeast by possibly underpitching. My question is should I raise the fermentation temperature in an attempt to throw off the sulphur twang or just let it run it's course?

Cheers

Boagsy

 

[Bribie G]

I haven't used this yeast but I too have had big variability in WYeast packs with the same yeast. Latest example being Ringwood which has behaved totally differently to the last lot I used. Maybe there were less viable cells in your pack. Being as it's a top fermenter I reckon it wouldn't do any harm to give it a good rousing / oxygenation as it's only second day and hopefully the yeast is still capable of breeding up a bit further.

 

[Dazza_devil]

Thanks BribiG.
I stepped up a starter from a sample that I took from my first pack. The 2 litre starter fermented nicely and there was a good amount of slurry after I crashed it for 3 -4 days. I decanted most of the starter beer off the starter but I'm thinking perhaps that it hadn't heated up enough when I added some cooled wort before pitching. It was a cool night here and my starter with a litre and a half of wort appeared to be fermenting relatively slowly.
I've upped the tempmate to 20 degrees and perhaps I could give it a rousing.

 

[theredone]

wiki explains weizenbock as a german wheat beer that needs to ferments at 16-17. i would drop it from 19 if i were u.
i wouldnt worry too much about the smell. i put down a stella clone(and used a lager yeast) and it stunk of rotten eggs badly(sulphor). it mellowed quite alot by the time it was finished doing its bit and then after a few days ccing it was barely noticable and actually had quite a nice smell about it. id leave it be and not get to worried
edit: mine fermented at a pretty constant 14degrees but +/- 2 degrees every now and then

 

[Dazza_devil]

I've let it drop back to 19.5 degrees. I brewed a Dunkleweissen at 19 degrees C that was delicious and wanted a similar yeast profile in this brew but rotten eggs is far from banana and cloves, hopefully it will dissipate.
Would a higher gravity brew cause a less vigorous ferment with a relatively smaller krausen?

 

[Weizguy]

I've let it drop back to 19.5 degrees. I brewed a Dunkleweissen at 19 degrees C that was delicious and wanted a similar yeast profile in this brew but rotten eggs is far from banana and cloves, hopefully it will dissipate.
Would a higher gravity brew cause a less vigorous ferment with a relatively smaller krausen?

Depends on the health of the yeast.

I brewed a big 10% pale weizenbock on a full cake of this yeast, and it spewed out of the airlock at 13 C.

Was thinking that you may have underpitched, as yeast throws sulfur when under stress. Recently, I kegged a batch of weizen fermented on this very yeast strain, and it started to throw sulfur after the initial vigourous (as in, "popped the lid of the fermentor open") ferment.

 

[Dazza_devil]

The krausen looks to be dying down.
What effect would giving it a feed of perhaps 200 - 300g diluted dextrose have on things?

 

[brewerben]

Boagsy,

I've used this yeast a couple of times and my starters always smell of H2S (note: it is not SO2, which although produced by yeast is not produced in large enough quantities to smell at beer pH).

My final brews have been free from reductive (H2S) aroma, in fact I love this yeast, I find the 3068 too intense and overpowers any subtle malt character there may be.

If you're really worried in future you can add yeast nutrients, but for mow just roll with it.

Ben

Mornin Brewers,

I have a Weizenbock OG 1.073 that's into it's second day of fermentation with Wyeast 3638 and is now giving off a fair amount of SO2 smell. I've had the tempmate set at 19.5 degrees and it looked to be taking off pretty well yesterday. I pitched a 2 litre starter at 19 degrees which was meant to be at high krausen but because of cold temperatures here it was fermenting slowly. There was a lag time of 10 hours or more before I noticed visible signs of fermentation. I was expecting a huge krausen like the last time I used this yeast so I installed a blow-off tube but it's seems to have levelled off now at around two inches. I'm assuming that I have stressed the yeast by possibly underpitching. My question is should I raise the fermentation temperature in an attempt to throw off the sulphur twang or just let it run it's course?

Cheers

Boagsy

 

[Dazza_devil]

Thanks for picking me up on that one Ben, Hydrogen Sulphide is in fact the culprate I was intentending to name as opposed to Sulphur Dioxide.
A poisonous gas so I had better not siff it too much.
My starter smelled delicious but I'm thinking that my slurry was still a little cold (room temp has dropped here in the last couple of weeks) when I gave it a feed of wort which has knocked my yeast count about a bit, hense stressing it out during the ferment.
Where does the Sulphur come from to form this compound, sulphates in the water?
I got this from wiki which is perhaps relevant,

'Sulphate reducing bacteria generate usable energy under low-oxygen conditions by using sulfates to oxidise organic compounds or hydrogen; this produces hydrogen sulfide as a waste product.'

 

[Dazza_devil]

Just an update here.
It must be around day 11 now and I can't detect any sulphur at all coming from my fermentation fridge. In fact I can now detect what seems to be a rather pleasant aroma and I'm now having high hopes about this beer once again. It did get to the point where it nearly knocked you over when the door was opened at one stage so it just goes to show you what a bit of time and patience can do.