Souring Watermelon Juice to Pump Up Berliner?

[RocketOtter]

Long time lurker, first time poster.

I have a Berliner that I pitched with WLP630 Berliner blend that has been in the primary for 5 weeks at 68-70º and is far from sour, just barely tart. I have read many places that the WLP630 can take many months to sour, if it sours at all. I have a gallon sized lacto D culture and was thinking of juicing a watermelon, adding some lacto to the juice (around 6 cups of juice), letting it sour @ 100º for 3-4 days and adding it to the carboy to increase the sourness of the batch.

Has anyone tried anything like this with good/bad results? Any recommendations on alternative ways to quickly increase the sourness of a Berliner?

 

[CadillacAndy]

The easiest way to increase the sourness would be to add lactic acid. It's usually available at your homebrew store. While it's not the greatest to rely on to turn a clean beer sour, I've often used it to increase the overall acidity and sourness of Berliners that are just a little lacking. I usually take a measured amount - 12 oz usually and add lactic acid with an eye dropper. Once I hit where i want I make some notes and either scale up for the batch volume or just keep adding directly to the bottles.

 

[RocketOtter]

Thanks for the reply. I was tying to avoid "cheating" with the store bought lactic acid, aiming instead to make the acid with the bugs. I went ahead with souring some watermelon juice with lacto D. just to see what will happen. The juice/lacto mixture has been going at 100ºF for 24hrs and I plan on checking on it tomorrow to see where the sourness is. If it's not sour enough I'll probably go with your suggestion of adding lactic acid.

 

[Johnnyhitch1]

update!

Keeping it warm on a heating pad?

 

[RocketOtter]

I let the juice sour for 48 hours at 100F before adding it to the beer. It got a little tart but not very sour. I'm starting to think that the WLP677 strain I used just isn't very potent. I'll give it a week or so before sampling it again.

I kept it warm using a lamp in a cardboard box covered with a blanket. It worked surprisingly well.