Complex sentence: The issue came to a head in 1908, when a royal commission was appointed to investigate the issue, by which point 60% of all whiskey produced in Britain and Ireland was made in Coffey stills.
Split into simpler sentences: The issue came to a head in 1908, when a royal commission was appointed to investigate the issue. By this point 60% of all whiskey produced in Britain and Ireland was made in Coffey stills.