I've got a batch which I pitched with stepped up Bam Biere dregs.
The bottle I'm pretty confident was quite fresh, I'm not far from Dexter, MI and my local grocery carries it from time to time (I say time to time since it sells out relatively fast when they have it stocked) so I'm assuming it's usually pretty fresh.
I threw the dregs into a pint jar of starter wort and let them sit a month or so, actually got a kombachu like scoby forming on the top of that (it was covered with foil but had basically free oxygen exchange with the outside).
I did a 12 gallon batch with this recipe:
OG: 1.046
FG: Don't have my log right here for that, but it was low 1.002-.003
9lbs 4oz Pilsner
4lbs 10oz American 2-Row
2lbs 12oz Wheat Malt
1lbs Flaked Barley
8oz Carared
1oz De-bittered Black Malt
1oz Hull Melon @ 60 minutes
1oz Hull Melon @ 40 minutes
.5oz Hull Melon @ 0 minutes
Mashed for 90 minutes @148 degrees
60 minute boil
Long low temperature mash is a key part of JP's process I feel, it ensures the wort is very fermentable and allows these beers to be bottled fresher because the bugs and the yeast have easily eaten up all the available sugars. Regular Bam Biere uses Crystal, but I had a bunch of Michigan Hull Melon and decided to use that instead. I haven't dry hopped it but might toss .25 oz of hops into the keg when it is ready to go in the kegerator.
I pitched a large starter of WLP-510 Bastogne Belgian Ale Yeast and my whole pint jar of stepped up Jolly Pumpkin Dregs including the kombachu scoby looking thing. I ferment in 15 gallon food grade plastic barrels, but during the summer I have some fruit fly issues so to avoid them getting into the wort I covered the top with a cloth strapped to the top of the bucket. This lets it get free exchange of oxygen and ferment 'openly' for the first few days which I think helps to simulate JP's process without allowing for additional uncontrolled inoculation. After about 4 days as activity started to die down I put a regular cover and airlock on it and let it ride.
Brewed it on 6/13/2015. I tasted it about a week ago and kegged it up. I'm super happy with it, turned around in under three months and already has a great character both in the aroma and the taste that reminds me of Jolly Pumpkin's fresher beers like Bam Biere. It's naturally carbonating in the kegs now, can't wait to get it on tap.
Admittedly my turn around on this beer is fast, I'm not sure if I was bottling if I would do it already, but I feel completely safe putting it into a keg with a bit of priming sugar. Never heard of a keg bomb.
I highly recommend anyone who wants to try a fast turn around sour to give it a try with a low mash temperature and JP Dregs. I'm super excited about how this one turned out and already planning another batch, I saved a pint of dregs out of that last batch, even found what was left of the floating scoby that formed. Next time might something darker like Bam Noire.