G'day there
Infections are not always the problem with finish beer flavour, taint from proteins and tannins that build up on
Biofilm and surfaces have a huge impact on beer flavour. The latter is a major concern in the dispense area and alot of work is being done by scientists around the world. Proteins and tannins need an attach point, and this is usually biofilm (which make sticky residues, perfect for grabbing onto) and calcium oxalate (beer stone). Both love dark, wet environments which kegs and heat exchangers basically are.
Things like beer stone and biofilms are hard buggars to get off; caustic solutions dont do the job. When it comes to biofilm, caustic makes the protective layer of the biofilm thicker and more impervious to the solution, they adapt to their environment, and with the heat it acts to burn on the proteins and tannins rather than remove them. Oxalate is usually attacked by strong acids, bad for the metal surface and for you when it spills on you.
2 years ago I met some scientists who came into the brewery, took samples and went away. They threw alot of money and and serious Phd type- research into some trials and 10 months ago came back with a
multi enzyme brewery wash. (note, still a few things to tidy up, like the website). This we have been using at 3 test sites with huge effect. It is safer than traditional caustic/acid solutions, better for the environment (once the enzymes have thier party, they then start knocking each other off) and easy to use.
When I finish my bit in the next week for the product, I'll put things up in the retail shop. A warm (50c) soak with the solution is an excellent start ...
Scotty