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Before knowing how dry ice is manufactured, you need to know that, unlike “wet” ice, it is not made of water (H2O), but of carbon dioxide, the CO2 that we expel in our breath. If in the gaseous form CO2 is the famous carbonic gas, in the solid state it is the dry ice that ice cream makers use so that popsicles do not melt on the beach. To manufacture it, you need to collect raw materials. Although carbon dioxide is present in the atmosphere, manufacturers do not extract it from the air, but from the “waste” produced by other substances. The production of ammonia, for example, releases CO2, which is sucked through a chimney into a special tank. There, it is cooled and compressed until it reaches a temperature of -28ºC and a pressure of 300 psi, about ten times the pressure inside a car tire. From there, just open the valve that closes the tank in an environment with normal pressure. “When that happens, the CO2 expands. Half of it turns solid, half turns to gas. We use the solid part, a very fine dry ice, which will be pressed in the form of blocks, cubes or small cylinders to be sold”, says Antônio Alberto, production manager of a multinational in the sector. The advantage of dry ice over wet ice is that it maintains an average temperature of -80°C. That is, it is much more “cold” than “wet” ice. One last – and obvious curiosity: do you know why dry ice has that name? It’s because, when heated, it goes straight from a solid to a gaseous state, without turning into a liquid.