Dry Ice: What It Is, How It’s Made, and Why It’s Important

Everyone knows what ice is — ice is simply frozen water.  Most ice that people consume and ice that occurs in the winter, encasing lakes, ponds, and the occasional puddle, is known as water-ice.  Unless you fall through it or you happen to be unexpectedly driving across is, ice is relatively harmless, keeping beverages cold and providing lovely skating surfaces for children in the winter.  There is a different kind of ice that is not derived from water, but is just as important.  Dry ice is different, as it is formed from frozen liquid carbon dioxide.  Ice that we use in drinks is known as water-ice to scientists, and this is one of many differences between it and dry ice.

How Is Dry Ice Formed?

Dry Ice is the solid form of carbon dioxide.  Carbon dioxide is the gas that anything living on earth exhales—animals, insects, and people all exhale carbon dioxide, and when this gas reaches the correct temperature, much like frozen water, it freezes and becomes a solid, thus making dry ice.  It is considered to be a cooling agent, but because of its extremely low temperature, frostbite may occur if someone tries to use it or touch it without proper equipment or gloves. 

How Is Dry Ice Produced?

Many corporations make dry ice, and it is used as a refrigerant.  Dry ice is produced as a by-product from such processes as ammonia nitrogen from natural gas production, oil refinery work, and large-scale fermentation.  It is produced when carbon dioxide gas is liquefied, then frozen at extremely cold temperatures.  There are 3 standardized forms of dry ice that are typically available: large blocks, small cylindrical pellets, and tiny cylindrical dry ice pellets that will not stick to skin and will float in water or oil.  Dry ice has a wide variety of uses in a number of industries and is prevalent when food companies need to do flash-freezing.  Flash-freezing helps keep perishable foods longer than traditional freezing methods.  Since dry ice is readily available and easy to maintain, there are numerous uses for it.