Most nice bourbons are meant to be consumed without ice, but maybe with a few drops of water to bring out the flavors. Sometimes an every day bourbon calls for ice. We love skull ice cubes, but not for bourbon. The perfect ice for bourbon is not a cube. Its is a big, round, sphere. They cool down the drink but, more importantly, take a long time to melt so they wont water down your bourbon.
For my first round of ice balls, I forgot that ice expands. The ice actually poured out of the top of the mold and nearly split the seam. My balls were perfect when I filled the mold with just enough water to reach under the hole at the top of the mold.
Buy the ice molds here and enjoy a cold bourbon with perfect balls.