Was it because I'd just had the coffee IPA? Or maybe my palate has just grown a lot since last time. I found this to be mellow, rich and chocolaty, with a lot of barrel character but not overwhelmingly so. Call me a new fan!

It's a cocoa chocolate versus a milk chocolate. Not as sweet and viscous I keep imaging it would be from the large "CHOCOLATE" text on the label. The imperial, more bitter, part of the stout probably has a part in this in addition to some of the oak-aging.