I jumped ahead 50 years in my research out of an interest in seeing how the paper I am currently trawling through - The Carlow Sentinel - had changed in the interim, and to see what beer was being advertised in the town. I landed in January 1901 to be greeted by the following advertisement:
[The Carlow Sentinel January 1901]
According to an excellent article on the arsenic-in-beer epidemic of 1900-1 by Matthew Copping on The Brewery History Society website, the poisoning was traced back not only to the sugar production process but also to arsenic transmitted onto the surface of malt during the kilning process.
Either way it seems that scaremarketing was being used to sway consumer purchasing habits then as now.
I'd love to read Professor McWeeney's book but sadly I can't find it online...
[With thanks to the Local Study Room at Carlow Library]