● Yeast and mold is surface growth on parts of the beer system that gets exposed to the air. Those parts include drains, faucets, and keg coolers.
● Beer Stone results after the barley change into malt, creating oxalic acids or salts. When the beer is dispensed in cold temperatures, calcium oxalate, or beer stone forms, it builds up in the tubing, eventually flaking off into the beer.
● Bacteria can cause the beer to taste off or have a bad smell. When beer smells like rotten eggs or has a sour taste means bacteria contaminated the beer.