Bottle conditioning accidentally sour beer

[Captain Damage]

Ten weeks ago I racked a pale ale onto 48 oz of raspberry puree. The beer is still fermenting and apparently going sour. My expected FG (taking the sugar from the raspberries into account) was 1.011; it's currently at 1.004 and still going. The sour flavor isn't very pronounced yet but I don't think I want it to dry out any more.

Is there a standard procedure or any kind of rule of thumb if I want to bottle it now? I know I'll have to throw it all in the fridge before they turn into bombs, but should I add sugar, or a less-than-normal amount of sugar, or just let it carb itself?

OG was 1.048 (again, that's including the sugar from the raspberries) Yeast was Wlp001.

 

[hector]

It can be a sign of infection with wild Yeast .

Hector

 

[Captain Damage]

I'm well aware that a bacterial or wild yeast infection is causing this over-attenuation "behavior." My question is that since the beer isn't ruined (yet) what is the best way to bottle condition it?

 

[smizak]

That's a tough spot. You might have to let it finish out. I don't think it will go much below the 1.004 it's already at. It may turn out great.

 

[Captain Damage]

I decided to go ahead and bottle it just this afternoon. The signs of activity - mostly the persistent ring of fine bubbles along the edge of the surface and occasional airlock activity - still hadn't abated. I bottled with 4.5 oz of sucrose (in 5 gal) for a carb volume of about 2.6. I'll check one every few days or so and when they are where I want them I'll throw them in the fridge.

 

[ghpeel]

Yikes, be careful with them, and store the bottles in a place that you won't mind mopping down later if they burst. Hopefully, they were done. Its possible that the extra pure sugar from the fruit is what dropped your gravity so low, and the taste is coming from their natural acidity and not a wild yeast strain taking hold.

 

[Captain Damage]

Boring details department: I brewed the partial mash pale ale base and let that ferment out. Two weeks after my initial pitch, I racked it onto the fruit, which was a can of raspberry puree which I'd heated up on the stove because sometimes I'm a bit of a moron. That yielded the expected re-fermentation and I left it for three weeks. All seemed fine, but it was very cloudy because of my heating up the fruit and setting the pectin, so I added some pectic enzyme which cleared it up very nicely.

A couple days after it cleared I took a gravity reading in anticipation of bottling two days later. The FG read 1.011 and it tasted great - and it was pink! (something for the ladies ) Then, when I went to bottle it two days later, I notice it had grown a ring of fine bubbles around the perimeter of the surface and the airlock was showing activity, so I put off bottling till the next week...which stretched to a few more weeks until I decided to bottle today.

It was definitely not "done" when I bottled. The same signs of continuous slow fermentation were still there. FWIW, there was no pellicle, so I'm thinking it's more likely bacteria than wild yeast. It still tasted good, not as good as my first taste weeks ago, not funky or acetic. And it's still pink - I've never seen a beer this color. I don't know what part of my process or equipment introduced this infection, but obviously I'm revisiting my sanitation procedures and checking my equipment, even boiling a lot of it.

BTW I used the nutrition information on the label to calculate how much sugar I was adding to the beer. Just number of servings per container x grams of sugar per serving. I went under the assumption that all the fruit sugar would be fermentable.

 

[HHP]

You already bottled so thats that.

I think you'll be alright, 1.004 is pretty low, but i doubt it will go down much more, maybe a point or two.

I doubt that will produce bombs, but i never bottle so I have no real world experience.