Gday all. Over the last few brews I've noticed a brown build up inside my kettle especially on the bottom is this an issue with any off flavours that may be imparted from this? I don't really pay to much attention to my kettle I give it a quick squirt out before brew day and that's it. I sat some sodium percarbonate in there over night and gave it a good scrub this morning with a strong bristled brush but it's pretty stubborn stuff. I hear phosphoric acid may be a better option. What do youse do with your brew pots do you clean em till bright and sparkling after every brew or are they a bit like mine with a bit of staining from previous brews?