Melbourne (Australia) has a ton of beer events this week as part of Good Beer Week. I went to a sour beer event last night which had a few beers from four brewers. One brewer had a basic beer base and brewed three different batches - one with lactic, one with acetic and one with malic acids. Very interesting to compare the three. The acetic one was pretty funny, he'd used 2L of the cheapest vinegar he could find in a 20L batch.
One of the standouts of the night was a light peach sour, which was started in 2011 and racked onto peaches a year later. Incredibly complex, really amazing stuff. The other was a soured stout made from second runnings of a Russian Imperial, racked onto blackberries after 11 months for a further three months.
Really eager now to kick up my sour beer production, only have one at the moment but might find ways to increase this by brewing bigger beers and having a crack at light ones with second runnings.