Yeast contamination can be an issue, as can water sourcing.

Well yeah, that's why you use a well-run brewery until you can afford the upkeep of your own. Besides, Meantime is a great brewery. I doubt those concerns - while legitimate - were high on the list with that brewery.

Was a great independent brewery now a SABMiller profit center.

http://www.bbc.co.uk/news/business-32747973

I think water (assuming the brewery is competent/has decent quality control) is a big issue wrt resulting taste. Anything we drink is mostly water after all. This is the only explanation I have for why all the "Japanese" beers one can get outside of Japan taste so awful -- they're all produced on license -- and I assume the recipes are the same. Note I'm talking about industrial beers here -- so hardly the best beers in the world -- but I still think they taste markedly better if you get them in Japan. Could be a consequence of rosy memories, of course.

The really excellent homebrew site brulosophy focuses on doing triangle tests to determine which factors have the strongest influence on the resultant beers - while a shocking number of things they've tested don't reliably produce a noticeable change in the finished product, water chemistry was one of the few where there was a reliably significant difference.

http://brulosophy.com/2015/04/06/water-chemistry-pt-1-mash-m...