Before I start this post,
here is an interview with Telegraph's Brian Thompson on the Beer Samizadt blog. Since I read this post I've had made it a point to try
Obscura Petit (which I had seen on tap at Pizza Port Ocean Beach) and
Obscura Arborea (which I had purchased a few months ago). Petit is a tart, sour beer that weighed in around 4.5% abv. What a delicious beer. It's a sour without sweetness. A subtle bitterness appears in the finish and complements the sour. Petit is my favorite type of sour, moderate alcohol, lively, funky sourness, and limited sweetness.
Obscura Arborea is a different animal from Petit. Arborea is a 9% Oude Bruin, or Flanders Brown Ale. It is malty and aged in oak, and I picked up the oak, especially at the front of each taste. The sour flavors were behind the malt and oak. Like Petit, Arborea is not sweet, and I found it a dry beer. Without reading the label, you'd never know this beer was 9% abv. The beer was thinner than I would have expected, and it's sourness was muted. I think this beer would have benefited from a bit more sweetness, which, I know, is strange for me to state after just writing how I prefer sours that aren't sweet, but this would have given it a richer profile.
I've never been bitten by the barrel aged bug, and Arborea is oaky from its time spent in barrels. Its oak overshadowed the yeast and related sourness. I liked this beer and would buy it again, I think I was just expecting more from it. I've had several Oude Bruins, but am no expert. I need to find a style benchmark so I can properly gauge sour beers.