Yes, the ABV raises or lowers depending on temperature and humidity. The Stagg almost certainly went in at 125 proof (barrel entry proof), so it got a big boost

Yes, the ABV raises or lowers depending on temperature and humidity. The Stagg almost certainly went in at 125 proof (barrel entry proof), so it got a big boost during the considerable aging process. I've heard descriptions (from the producers) of barrels that gained / lost proof depending on what floor of the warehouse they were stored on. Pretty neat.