The ball on the far left was made from plain tap water – never boiled, never filtered.  The 2nd ball from the left was made from tap water which I boiled for 3 minutes, then cooled, then boiled again.  The 3rd ball was made from water I filtered through my Brita then boiled once.  The ball on the far right was made from filtered, double-boiled water.  Can you see the difference in clarity? Yeah, me neither. My goal was to make clear ice – that is, ice that is totally transparent without any haziness or white fissures.  I know that commercial ice makers use fancy processes like upside down freezing, but several websites propose that you can make your own clear ice just by boiling (or double boiling) water before freezing.  I put this to the test, and as you can see, my results were less than stellar.  The complication may have to do with the ice ball molds I was using.  The molds are sealed, so it’s possible that some gasses (or evil spirits) weren’t able to escape during the freezing process.  I’ll try again with regular cubes or blocks, but for now, I’m a little pissed that I’ll have to chill my morning gin with cloudy ice.