Complex sentence: In the Cotswolds, prunes were fermented to form a cider-like drink called jerkum which, due to the high sugar content of prunes, was considered particularly potent in alcohol content compared to contemporary ciders and beers.
Split into simpler sentences: In the Cotswolds, prunes were fermented to form a cider-like drink called jerkum. Due to the high sugar content of prunes, it was considered particularly potent as compared to contemporary ciders and beers.