Berthold Keller is a beer brewed in Belgium by Brouwerij Martens NV
It's classified as a pale lager and contains 5% alcohol
It is ranked #2 out of their 13 beers. 
Beer = Berthold
Cellar = Keller
Brouwerij Martens NV is a family run company which was founded in 1758. It is one of the oldest breweries in Belgium. They also operate the largest beer museum in Europe.