Crushed ice is smaller than your typical ice cubes. When a recipe calls for crushed ice it is important to use crushed ice. Crushed ice melts faster, diluting the drink. Recipes that call for crushed ice rely on this dilution. You can buy a big fancy ice crusher, use the crush mode on your refrigerator door, or just cover some ice with a towel and smash it with a hammer. If you need crushed ice for several people you can also get something called a Lewis Bag. It is a cloth bag you put ice in, and then smash the ice with a rolling pin, or hammer.