Ice cube trays are incredibly useful to have around, because they can be used for more than just freezing water. There are a number of different ice cube tray styles on the market, and many cooking supply stores sell a wide assortment for different needs. In addition to freezing ice for drinks, ice cube trays can also be used to freeze things like stock for quick bouillon cubes and fruit puree for perfectly measured iced smoothies. You might also want to try freezing things like fresh fruit or herbs inside the ice, so that the ice cubes will be decorative and flavorful.
There are three basic materials which ice cube trays are commonly made from. Most consumers are familiar with plastic ice cube trays, which are flexed to loosen the ice cubes so that they fall out. Over time, however, plastic trays have a tendency to crack, which can be quite irritating. Metal ice cube trays are also available, typically with a handle which shifts a movable section to break up the ice cubes. Finally, many companies make ice cube trays from silicone, a highly flexible material which can be molded into a variety of shapes.
Some companies also make ice cube trays with lids. The lid is designed to minimize freezer odor, so that the ice cubes will not be flavored by other things in the freezer. Lids also help to prevent sloshing water, which can be a problem when filling ice cube trays, and they usually slide along the tray, so the cook can extract the desired number of ice cubes without worrying about emptying the entire tray.
In addition to the familiar rectangles, ice cube trays can also be molded to yield an assortment of shapes. Squares, triangles, circles, and hearts are all fairly common, as are novelty shapes like LEGO® blocks, shamrocks, and animals. Sometimes, the shapes are designed for a specific purpose; long narrow ice cubes, for example, can be easily inserted into bottled beverages to keep them cool. These ice sticks can also be used in tall glasses for an unusual presentation of a cold beverage.
When selecting ice cube trays, try to find sturdily constructed trays which will hold up through years of use. If you are looking at silicone ice cube trays, flex the material; if white streaks appear, it is not high quality silicone. You may also want to consider potential uses for ice cubes in your household, and if you plan on freezing flavored foods like bouillon and fruit, you may want to get dedicated ice cube trays for this purpose, so that your plain ice does not acquire a strange flavor.