Explainer

How is dry ice made?

Dry ice is just carbon dioxide in solid form — but turning a gas into a frozen block takes a specific process. Here is how it is made, the forms it comes in, and the science that makes it so useful for keeping freight cold.

What makes dry ice different

Dry ice is the solid form of carbon dioxide (CO₂). What sets it apart from regular (water) ice is that it does not melt into a liquid — at normal pressure it sublimates, passing directly from solid to gas at about −109.3°F (−78.5°C). That is why it leaves no residue and why it keeps things far colder than water ice ever could.

The process, step by step

Production turns captured CO₂ gas into a solid through pressure and rapid expansion:

  • Capture and purify the CO₂ — carbon dioxide is collected (often as a by-product of other industrial processes) and purified for use.
  • Pressurize and cool it into liquid CO₂ — under high pressure and low temperature, the gas becomes a liquid that can be stored and transported.
  • Rapidly expand it into dry-ice "snow" — releasing the liquid CO₂ to lower pressure makes part of it flash-freeze into fine, snow-like solid particles while the rest escapes as gas.
  • Compress the snow into shape — the dry-ice snow is pressed under high pressure into the final form: dense blocks, flat slices, or small pellets and nuggets.

The forms it comes in

  • Blocks — dense and slow to sublimate; best for long transit and large loads.
  • Slices — flat slabs cut from blocks; easy to layer in shipping cartons.
  • Pellets / nuggets — small pieces that pack around irregular product for fast, surrounding cooling.

Why the form matters for shipping

Because every form is the same −109.3°F CO₂, the choice comes down to how long the cold must last and how it is packed. Denser blocks hold cold longest; slices layer neatly above and below product; pellets surround irregular shapes. Matching the form (and the quantity) to the trip is exactly what makes a dry-ice shipment arrive cold — and it is what our specialized-services team scopes for every dry-ice move.

Frequently asked questions about dry ice

Is it safe to touch dry ice?

Not with bare skin — at about −109.3°F it can cause frostbite almost instantly. Always handle dry ice with insulated gloves and tongs.

What happens if you put dry ice in water?

It sublimates rapidly, producing a thick fog of CO₂ gas and cold water vapor. It is a dramatic effect, but do the it only in a ventilated space — and never seal the container, as the gas builds pressure.

How should dry ice be stored?

In a well-insulated cooler in a ventilated space — never in an airtight container (the CO₂ gas needs to vent) and never in a sealed vehicle cabin. It sublimates continuously, so buy it close to when you need it.

Is the gas released from dry ice harmful?

CO₂ is non-toxic, but in an enclosed, poorly ventilated space it can build up and displace oxygen, which is dangerous. Always use dry ice with good ventilation.

Have a shipment that needs dry ice?

Tell us what you are moving, the destination and the transit time and a specialist will scope the dry ice, the form and the compliant packaging.

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