You weren't there either, but you have a lot to say about about the "*******" beer they drank. I simply turn your own words back on you. By your own definition, you don't know either.
But there are many records from boroughs and other town administrations in the UK and elsewhere in Europe that identify beer quality as a major local issue. They knew the difference.
Good and bad are subjective, not absolute. What would a medieval monk think of modern beer, like VB?
Making good beer did not begin with the invention of the STC 2000 and Starsan.
Getting back to the OP's question:
If you want the good oil on car tyres don't ask a tyre maker, ask a race driver.
If you want the good oil on yeast don't ask a yeast maker, ask a brewer.
Which is what the OP did. Pity so many 'brewers' betray their craft by ingoring their own and other brewers' experience.