When to bottle Berliner weisse

[adam62cb]

Hey everyone, I recently made the no boil single decoction Berliner weisse recipe from NB. It started off slowly, but then steadily fermented and produced a layer of "white mold" floating on the top of the Carboy. It has been around two and a half months, there is still a layer of white mold on top and the gravity has dropped to less than 1.01. My question is, when is it appropriate to bottle? Should I wait for the Top layer to dissipate or for the FG to hit a specific number? I haven't tasted yet so does more time equal more sour? it appears very light and clear, but I expected the activity to cease by now. Lastly, do I just rack from the bottom under the white mold layer? Lastly how concerned should I be with contaminating the bucket, thief, & racking cane, etc?

 

[GilSwillBasementBrews]

At 1.01 I would think your done. Yes, when you rack to bottling bucket or keg just rack from underneath the white layer.
I'm not all that experienced on sour beers however, I'm sure if I've misled you someone else will be more than happy to chime in with where I've steered you wrong.

 

[skibb]

From my understanding measuring FG isn't an accurate indicator to whether or not the lacto is still active and producing CO2. Hydrometers measures the weight of the solution and the lactic acid produced from weigh just a little less than the residual sugars but not nearly as little as ethanol (as far as we can tell with our basic equipment). Lactobacillus delbrueckii does stop working when it reaches a ph of about 3.8, so perhaps measuring the ph of your beer will give you a decent idea if the lacto is still active or not. Regardless, it shouldn't be producing tremendous amounts of CO2 if its near that number so I would say it would be safe to go ahead and bottle it. Maybe after giving it a couple weeks to make sure it fully carbs up you can store it in a nice cool place (like a fridge) to inhibit any more lacto activity.

I brew a Berliner yearly and I have always pitched the lacto after primary fermentation (at which point the FG is already around 1.005), I let it condition with the lacto for at least 3-4 months before bottling. The pellicle has dissipated at this point. Next time I will measure the FG again after this conditioning time and see if it has decreased any. So far, I haven't had a problem yet with bottle bombs or overcarbonation.