Brewed a simple blonde recipe and pitched a jar of Wyeast 3763 Roeselare slurry from a previous batch. There wasn't a peep out of it for about 5 days, so I pitched an emergency pack of Mangrove Jacks Belgian yeast I had from last years brewcon. Kicked off fairly quick after that, left it alone in carboy for 3 months, except to add some Cantillon dregs at one stage. I think the seal on the carboy should have been fairly good, no sign of a pellicle.
Today transferred to keg to secondary it for another few months, gravity is currently 1.012. However, the sample was very sour. Not unpleasent, but I think it's verging into vinegar territory. Not a whole pile of complexity, it reminds me of a berliner right now. Is this a bad sign, or will it round out over time? Thanks.
Based on your description I'd say check the pH to see what it's at. If you want more complexity pitch some Brett
That SG is very high for Wyeast 3763 Roeselare. For that beer style you'd expect to get to at least 1.006. I'd pitch more Brett and leave for a longer period of time.
It's still far too early to know what it's going tontuennout like. Dregs for other sours are a great way to go introducing new strains as you will get a variety of funk producing bugs. Just hide it away for another year and it'll be grand.
Probably always better to pitch a fresh sacc strain with a sour slurry.
Is it vinegar as in acetic or just tartness?
+1 on leaving it longer. Worst case scenario, it's too sour to drink on its own, you can always blend with other beers to add sourness.