Although they look beautiful in glasses of whisky, perfectly spherical Japanese-style ice balls are not just meant for aesthetics. The large surface area allows the ice to melt much slower than regular cubes, keeping drinks cold without becoming too diluted. You've probably seen bartenders chip away at an ice ball, but never quite caught the process from start to finish. So here's how the professionals make the perfect ice ball:1. Start with clear, compressed ice that has been made by directional freezing, meaning there are no impurities or trapped air inside. Using this type of ice is very important as ice with air trapped inside will melt faster, defeating the purpose of using an ice ball.2. Saw the ice into large blocks.3. Take one block of ice and chip away at all eight corners with an ice pick.4. Start chipping the ice away from you at a slight declining angle. It is important to pick at the surface of the ice, not into the ice.5. Keep rotating the ice in your hand and chip at all angles until a sphere shape emerges.6. Once the sphere is complete, take a paring knife and shave the ice ball so that it has a perfectly smooth surface. The smoother the surface area, the slower the ice will melt.