While Japan's major breweries continue to report flat beer sales amid an ailing economy, there is one Hokkaido-based beer maker that's brewing up a storm.

Otaru Beer in the port city of Otaru has continued to flourish since its inception 15 years ago, with output growing at an annual average of 10 percent. At its head is a man who hails from a village near Frankfurt with a population of just 500 people.

Braumeister Johannes Braun, one of just two German nationals residing in Otaru, attributes the microbrewery's success to a surprisingly simple recipe. "I brew beer — real beer, using only natural ingredients," he says. "Many breweries in Germany still abide by a law governing beer production that dates back almost 500 years. I follow that law to the letter."