Souring a Guiness - just how funky should this get?

[Elden]

I am brewing a Guinness clone, and as part of that I am souring a can of Guinness. It is getting really nasty, I'm having trouble with the idea that I am really going to put that crap into beer.

I put a can in a bowl with about 2oz of malt, covered loosely with foil, really just to keep bugs out, and let it sit. It has been 4 days, and the smell is, well terrible, but the right sort of really strong sour smell. Problem is it has a layer of what looks like white mold growing on top! I think there is more growing on the barley at the bottom. Its really, really foul looking. I know I am deliberately contaminating, but I wasn't expecting it to look like that! Is that ok?

My plan was to boil thoroughly and put it in when I rack to the secondary, so I have time to try this again if I screwed up.

 

[redm18]

I did it without any malt just a bottle of Guinness. No mold for me the beer just smelled slightly sour. I imagine you would be fine putting your beer in as you will be boiling it for 15 min

 

[ReverseApacheMaster]

There is probably a white film on top. This is a pellicle. It should be lactobacillus, which is what you want for souring. After four days you are probably ready to go.

If it is fuzzy on top then it is mold and you may not want to use it.

 

[Elden]

A white film is probably a better description than mold. I'd never heard of a Pellicle before, but that fits. I think this may be a bit thicker than the pictures I can find here, but it sure looks right. Theres actually quite a bit more information on this site if you know the word to search on!

OK, i feel much better about this. thanks!

I guess its about time to boil and add. We need the funk!