About 15 months ago I brewed my first solo attempt at a sour. I had a pack of WLP655 Belgian Sour Mix 1 that was just out of date. I made a starter to increase the cell count. The recipe was 50/50 pale malt and pilsner lightly hopped, mashed at 68. I pitched the WLP655 starter and also US05 and let it go....about 9 months later i had a taste. A bit bland and no sourness. So i added 0.5 kg rhubarb hoping that would add some interest. Fast forward to now, after 15 months since initial pitch, and it is still a bit bland. It has a nice funkiness but no sourness. I wonder if the balance of the WLP655 got out of whack due to age and the starter? So i'm looking for suggestions....should I chuck in some fruit (say a kilo of raspberries?) Can i get it soured my adding more yeast at the same time?....any suggestions welcome. I really don't want to dump it and i guess that once carbonated it would be ok for summer but i want something more interesting.