WYeast 1007 German Ale

[Mguthriem]

Hi All,

Working on an Alt bier using WYeast 1007. It kicked off with a 2" thick Krausen that hung around for ages. Also a notable sulphur smell.

After 2 weeks, krausen finally began to dissipate, and gravity was unchanged from what I measured at 1 week (1005) .So, I transferred to secondary to and shoved it in the fridge at ~3C where I plan to leave it for 4 weeks.

Anyway, I checked it today (2 days after chilling) and saw something strange: the lid was distended and bubbles are coming *out* of the airlock. This is the opposite of what I expected, thought thermal contraction would suck air in.

I opened lid and got a rush of gas with a sulphur smell.

What gives? Is this stuff still fermenting at 3C?

Cheers!

 

[TheRedDarren]

I think it's called c02 evolution.
Basically there's loads of c02 in the beer from primary and when you chill it, it leaches out.
My theory on this is wobbly at best so don't quote me on it, but it's something along those lines.

 

[Mguthriem]

And the sulphur smell? I have read some stuff on forums that sulphur happens with 1007, but I thought it would dissipate after fermentation finished.


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[TheRedDarren]

Did you ferment at a low temperature? That yeast has a big range of 13 - 20 deg c.
Some low temp yeasts do give off a sulphur smell, these normally condition out or reach such low levels you won't notice in anything other than a lager, once the beer matures, and this yeast apparently matures pretty quickly.
I think it will be fine.

 

[Mguthriem]

It fermented at 16C. Thanks for the vote of confidence!


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[Simonh82]

I'm not sure CO2 is released from the beer at low temperatures. If anything it is the otherway around. As a beer cools the capacity to hold on to CO2 increases so I don't know why yours is bubbling now. I think even a true lager yeast would struggle to do anything at 3 degrees.

 

[Mguthriem]

I guess what I was worried about is if an infection could release gas also (although you would think any bacteria would go dormant just as the yeast).

After venting, the lid of the FV has swollen again, so it's still going on (whatever is is).

Bizarre.


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[Mguthriem]

Just to follow up on this. I still don't know where the pressure was coming from but, after 1 week lagering, all of the sulphur smell is the and it's tasting good. Guess theRedDarren was right :)


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