On Thursday, 15 February 2018 13:56:08 UTC, Dave Plowman (News) wrote:
In article ,
whisky-dave wrote:
I always put more in than I need otherwise completly emptying the kettle
results is some bits of calcium carbonate and other crude being poured
into the cup and I'd rather it stayed in the kettle.

Try rinsing the kettle with cold water once in a while.

I do, that is why the lip has a filter to collect the larger flakes.

I've tried using just the right amount, but you must realsie that after boiling some water gets lost via steam and stays in teh kettle. So boiling 250ml of water doesntl actually give you 250ml of boiling water, would have though that would be obvious when seeing steam. Pretty basic physics .