Unfortunately, it is never a friend, however, it isn’t always a foe either.
After a few brew sessions kettles and fermenters may start to carry a whitish or brownish coat. This is calcium oxalate, commonly called Beerstone. The main impact of beerstone on kettles is mainly cosmetic in that it makes the metal surface look tarnished. However, allowing the stone to build up in vessels that contain cooled wort / finished beer creates hiding spots for bacteria. In either case, what can we do about it?
Introducing Acids. (As always, be careful when handling chemicals).
Make a week acid using citric acid, or “Acid 5”, and mixing with water and soak the vessel for 30 minutes. The beerstone should then easily wipe off. Dry kettles for a few days to passivate the metal.
BS remover, from Five Star, is also an option. Follow directions according to the label.
I personally have not found beerstone to be an issue and rarely have to remove beerstone from my vessels.
