Open a valve on liquid CO₂ held at 300 psi and let it expand to atmospheric pressure, and at most about 47 percent of it lands as solid. The rest flashes to vapor at minus 109°F. That ceiling is set by physics, and it is the reason the industry rule of thumb runs about 1.5 pounds of liquid CO₂ for every pound of dry ice, and up to 2.5 pounds depending on how the plant is configured and how much of its vapor it recovers.
Those last two figures come from Maura Garvey of Intelligas Consulting, quoted by Packaging Dive in December 2025. The same reporting put U.S. dry ice production at about 4,600 tons a day, and dry ice at about 20 percent of U.S. CO₂ demand. The point of the ratio is simple. Every pound of dry ice on a loading dock stands for more than a pound of liquid CO₂ made somewhere upstream.
What Happens at the Nozzle
CO₂ can only be a liquid above its triple point, about 75 psia and minus 69.8°F. Bulk liquid sits well above that, near 0°F and 300 psi. A dry ice press drops it to atmospheric pressure in one step, through an expansion nozzle into a snow chamber.
Below the triple point there is no liquid phase to land in. The stream has to split into solid and vapor, and the heat that turns part of it into vapor comes out of the rest, which freezes. The snow collects at minus 109.3°F and a hydraulic press compacts it into pellets, nuggets or blocks. A 1983 patent on snow horn design, U.S. 4,415,346, states the limit plainly. When the liquid expands to atmospheric pressure, no more than a theoretical maximum of 47 percent by weight comes out as solid.
Colder, lower pressure feed liquid shifts the split toward snow, which is why some presses subcool the liquid before the nozzle. No amount of tuning moves the yield anywhere near 100 percent in a single pass.
Where the Other Half Goes
The other half of the stream leaves the snow chamber as cold, nearly pure CO₂ gas at atmospheric pressure. A press can vent it, or it can send it to a compressor and a condenser and turn it back into liquid for another pass.
That choice is the gap between 1.5 and 2.5 pounds of liquid per pound of product. A plant without recovery throws away more than half of what it buys. A plant with recovery is running a small liquefaction loop around its press, with compressor horsepower and refrigeration on every recovered pound.
Dry Ice Is Sold on a Short Clock
Dry ice gives up mass from the minute it leaves the press. A common rule of thumb for an insulated shipping cooler is 5 to 10 pounds lost every 24 hours, faster in pellets than in a solid block because pellets expose more surface. Each pound that sublimates becomes roughly 8.7 cubic feet of gas.
So dry ice is made close to where it is used, and nobody stockpiles it for a bad month. Garvey's figures show the supply side carries its own limits too. CO₂ plants generally run up to 350 days a year. Dry ice plants run about 275.
Why Dry Ice Feels a CO₂ Squeeze First
The Packaging Dive figures describe a market where demand and supply have been moving in different directions. Dry ice demand has grown about 5 percent a year for nearly a decade. U.S. CO₂ production capacity grew about 0.3 percent a year over the past 10 years. Intelligas expects dry ice to reach 23 percent of U.S. CO₂ demand by 2030, with industrial blast cleaning now its fastest growing use and pharmaceutical cold chain shipping adding to the pull.
Capacity has also been leaving. Garvey said two California CO₂ plants would close by the end of 2025 and one more by the end of April 2026, together close to 850 tons a day. "We're not in outright shortage," she said in December. "We could kind of get into a shortage next year."
Run the ratio against that. A ton of dry ice that a market loses takes 1.5 to 2.5 tons of liquid CO₂ to replace. Dry ice is the CO₂ product with the largest multiplier on its input and the shortest shelf life, so when liquid tightens, a dry ice buyer has the least slack of anyone in the queue.
The Liquid Settles the Grade
Dry ice packed against meat, seafood or ice cream is a food contact material. Airgas, for one, says it makes all of its dry ice from food grade liquid CO₂. A press turns liquid into solid and is not designed to clean it, so whatever spec the liquid met before the nozzle is the spec the dry ice buyer is relying on.
Beverage grade sits at the top of that range. The International Society of Beverage Technologists guidelines call for 99.9 percent minimum purity and roughly twenty individual impurity limits, with benzene held to 20 parts per billion. Beverage grade is the spec CleanCycleCarbon certifies to, and liquid that meets it can serve every food contact use downstream, dry ice included.
What the Ratio Means for New Supply
The same arithmetic sizes a new source. A renewable natural gas plant putting 1,000 MMBtu a day into the pipeline vents roughly 38 tons of CO₂ a day. Captured and purified, that is 38 tons of liquid. Pressed into dry ice, it is about 15 to 25 tons, depending on how much vapor the press recovers.
Replacing the roughly 850 tons a day leaving California would take more than twenty sources that size, before any of the 5 percent a year demand growth is counted. Intelligas has said the U.S. needs at least five new 300 ton a day CO₂ plants by 2030. RNG upgraders vent far smaller streams than that, at high concentration, and often much closer to buyers than a Gulf Coast ammonia plant.
CleanCycleCarbon's patent pending cryogenic purification was built for that kind of stream, and the company entered continuous commercial beverage grade production in December 2024. A dry ice buyer never sees the liquid behind the pellets. The supply behind the next cooler of dry ice depends on how much new liquid gets made in the next few years, at a spec good enough to touch food.
