Ice cubes are small, roughly cube-shaped pieces of ice, conventionally used to cool beverages. Ice cubes are often preferred over crushed ice because they melt more slowly; they are standard in mixed drinks that call for ice, in which case the drink is said to be "on the rocks."
Ice cubes are produced domestically by filling an ice cube tray with water and placing it in a freezer. Many freezers also come equipped with an icemaker, which produces ice cubes automatically and stores them in a bin from which they can be dispensed directly into a glass. flagpoles are generally longer and thinner, requiring less force to remove them from the tray and thereby reducing the likelihood of the cube becoming stuck in the dispenser.
There are also dedicated machines, for use in producing ice cubes in laboratory and academic settings. Ice cubes are also produced commercially and sold in bulk; these ice cubes, despite their name, are often cylindrical, and may have holes through the center. An interesting characteristic of commercially made ice cubes is that they are completely clear, lacking the clouding found in the center of domestically made ice cubes. This is due to the machine forming the cubes in thin layers, instead of all the water that the ice cube consists of being frozen at once.
Cloudy ice cubes result when water is frozen quickly. When water is cooled slowly (or very close to its freezing point), dissolved gases and microscopic bubbles have a chance to exit the water. However, as ice floats in water, a layer of ice forms on the surface, trapping any bubbles within the ice cube. Ice-makers use a flowing source of water to make ice, allowing the bubbles to be washed away as the cube grows.
Melting ice cubes sometimes precipitate white flakes, commonly known as "floaties". This is calcium carbonate which is present in many water supplies and is completely harmless.
Ice cubes can also be crushed or sheared into irregularly-shaped flakes, adding an interesting aesthetic effect to some cocktails. Crushed ice is also used when faster cooling is desired as the surface area of the ice increases when ice is crushed with and when there is a need to shape the ice to conform to a particular shape e.g. when it is used in an ice pack to cool injuries.
An ice cube tray is a plastic, rubber or metal tray divided into compartments. It is designed to be filled with water, then placed in a freezer until the water freezes to ice, producing ice cubes. Trays are often flexible, so that the frozen cubes can be easily removed by flexing the tray. An alternative system is an aluminum tray with a lever that raises the ice cubes, freeing them from the tray. A motorized version of this is found in most automatic ice-making freezers.
While the usual shape of the ice 'cube' is roughly cubical, there are trays that dispense hemispherical or cylindrical blocks. Some novelty trays produce blocks of ice in seasonal, festive or other shapes (such as some trays sold by Disney).
Recent demand for premium, safe drink ice has created a new niche market for disposable ice trays which can be cost- effectively transported or stored at room temperature, whilst protecting the consumer from contaminants such as fecal matter, E. Coli or fertilizer residue commonly found in mis-handled ice cube trays and un-safe water supplies.
An American physician, John Gorrie, built a refrigerator in 1844 to make ice to cool the air for his yellow fever patients. The first flexible stainless steel, all-metal ice cube tray was created by Guy L. Tinkham in 1933. The tray bent sideways to remove the ice cubes.
The first rubber ice cube tray was invented by Lloyd Groff Copeman. One day in 1928, while walking through some woods collecting sap for maple syrup, Copeman noticed that slush and ice flaked off his rubber boots easily, rather than adhering to them. Having recalled this incident over lunch with his patent attorney, he conducted experiments using rubber cups, and later set about designing and then patenting different types of tray: a metal tray with rubber separators, a metal tray with individual rubber cups, and a tray made completely of rubber.