What Temperature Do Soda Cans Explode in Heat?

Soda cans typically risk bursting when temperatures climb into the range of roughly 120 to 140 °F (about 50 to 60 °C), though the exact failure point depends on the can’s design, how much carbonation was dissolved at the bottling plant, and how full the can is. That temperature range sounds extreme for the outdoors, but it is surprisingly easy to reach inside a parked car on a summer afternoon. The relationship between heat and a carbonated can is really a pressure story, and understanding how fast that pressure builds helps explain why a forgotten six-pack can turn a trunk into a sticky disaster.

Why Pressure Climbs as a Can Gets Hot

A sealed soda can is a miniature pressure vessel. Carbon dioxide is dissolved into the liquid under pressure during bottling, and additional CO₂ sits in the small headspace above the liquid. At a normal room temperature around 72 °F (22 °C), the internal pressure in a typical carbonated beverage can sits in the neighborhood of 50 to 60 psi.¹ That is already a meaningful amount of force pressing outward on thin aluminum walls.

When the temperature rises, two things happen simultaneously. First, CO₂ becomes less soluble in liquid as the liquid warms, so gas that was happily dissolved in the soda starts escaping into the headspace. Second, any gas already in the headspace expands. Both effects push internal pressure upward. Under warm-weather or severe-service conditions, internal pressure can reach 90 psi or higher, roughly 50 percent above what the can experiences at room temperature.¹ At that point, the hoop stress on the can wall jumps from around 45 percent of the aluminum’s yield stress to roughly 70 percent or more, and the can begins approaching its structural limits.

The pressure curve is not linear. As temperatures keep climbing past 100 °F, pressure rises faster per degree than it did at lower temperatures. This accelerating curve is part of why a can might seem fine for hours and then fail quickly once conditions push a few degrees further into the danger zone.

How Hot a Parked Car Actually Gets

The most common place people encounter exploding soda cans is inside a vehicle left in the sun. Cabin temperatures in a parked car can exceed the outside air temperature by more than 20 °C (36 °F).² On a 95 °F (35 °C) summer day, that puts the interior air well above 130 °F (55 °C), and surfaces like the dashboard or a metal trunk floor can climb even higher. A can resting on a dark dashboard in direct sunlight can absorb radiant heat faster than the surrounding air, pushing the liquid inside to temperatures the can was never designed to handle for extended periods.

Cracking the windows slightly does reduce peak interior temperatures by a few degrees, but studies on vehicle heat buildup consistently show that even partially open windows do not prevent the cabin from reaching dangerous levels on hot days. A trunk, while shielded from direct sunlight through glass, also lacks any ventilation and can hold heat for hours. The takeaway is that any enclosed vehicle compartment in strong sun can push a soda can into the failure zone within a relatively short time.

It is worth noting that the 120-to-140 °F danger range for cans is also well within what direct sunlight can produce on outdoor surfaces like asphalt, concrete patios, or the bed of a pickup truck. A can left on a hot sidewalk in Phoenix or Dubai on a peak summer day is exposed to similar conditions as one inside a car, just without the greenhouse-style heat trapping.

Where Cans Fail First

When a soda can eventually gives way, it almost always starts at the bottom. The concave dome on the underside of an aluminum beverage can is an engineering compromise. That inward curve adds structural strength at normal pressures, but it is also the thinnest and most geometrically vulnerable part of the can. As pressure rises, the dome begins to push outward. At a critical point, it “reverses” suddenly, popping from concave to convex in a fast snap-through buckling event. This dome reversal is usually the first visible sign of failure and often the event that causes the can to burst open or start leaking.

Research on dome reversal has shown that the exact pressure at which it happens depends on several design variables, including the diameter of the base, the depth of the dome, and the depth of the dome shoulder (the curved transition between the dome and the can wall).³ A smaller base diameter, a deeper dome, or a deeper shoulder all tend to raise the reversal threshold. Manufacturers tune these dimensions to give the can enough margin above its expected operating pressure while keeping the amount of aluminum (and thus cost) as low as possible.

The side walls are also quite thin, typically well under half a millimeter on modern drawn-and-ironed aluminum cans. But the cylindrical shape distributes hoop stress evenly, so the walls hold up better than the dome under rising pressure. The top lid, which is a separate piece seamed onto the body, is generally thicker and stiffer than the bottom. So in practice, the failure sequence is usually dome reversal first, followed by a seam split or a crack propagating from the reversed dome, with the spray and mess that follows.

The Difference Between Bulging, Leaking, and Exploding

Not every overheated can detonates like a firecracker. More often, the process is gradual enough that you end up with a bulging can or a slow leak rather than a dramatic burst. The dome pushes outward and the can becomes wobbly, unable to sit flat. If the temperature stabilizes or drops slightly after dome reversal, the can might stay in that swollen state indefinitely, leaking carbonation slowly through micro-cracks in the seam or the reversed dome without ever fully rupturing.

A true explosive failure, where the can splits open and sprays soda in every direction, tends to happen when the temperature keeps climbing after the dome has already reversed or when the can has a pre-existing flaw like a dent or a scratch in the coating that weakens the wall. A dented can has a localized stress concentration that acts as a starting point for a crack once pressure gets high enough. This is one reason dented cans are more dangerous in heat than pristine ones.

The mess from an exploded can is disproportionate to its volume. Twelve ounces of soda under pressure can coat the entire interior of a car trunk, seeping into carpet, upholstery, and every crevice. The sugar dries into a sticky residue that attracts insects and can be genuinely difficult to clean. Diet sodas, which use artificial sweeteners instead of sugar, leave a less sticky residue but still stain fabric and headliners. Neither outcome is fun to deal with in a closed vehicle on a hot day.

Frozen Cans and the Other Temperature Extreme

Heat is the more common cause of can failure, but freezing a soda can produces a similar result through a completely different mechanism. When water freezes, it expands by roughly 9 percent. In a sealed can with almost no room for expansion, that volume increase generates enormous internal pressure that the can walls cannot accommodate. The failure pattern is different from heat-related bursting: frozen cans tend to split along a seam or crack lengthwise rather than popping the dome, because the expanding ice pushes outward uniformly instead of increasing gas pressure in the headspace.

Soda freezes at a slightly lower temperature than pure water because the dissolved sugar and CO₂ depress the freezing point, typically to around 28 to 30 °F (about −1 to −2 °C). If you put a can in a freezer to cool it down quickly and forget about it for a few hours, you are likely to find a cracked, icy mess. The explosion risk is real but usually less violent than a heat-related burst because the process is slower and the energy stored in compressed gas is lower. Still, a can that cracks in a freezer can leave frozen soda cemented to your freezer walls, which is its own kind of cleanup headache.

Variables That Shift the Failure Threshold

The 120-to-140 °F range is a useful ballpark, but several factors can push the actual failure point higher or lower for any individual can.

• Carbonation level: A highly carbonated soda like a cola or a ginger ale starts at a higher baseline pressure than a mildly carbonated drink. Higher starting pressure means less headroom before the can reaches its structural limit.
• Fill level: Headspace matters. A can that was slightly under-filled at the factory has more gas space above the liquid, which gives the expanding CO₂ a bit more room. Overfilled cans have less buffer.
• Can material: Most soda cans in North America are aluminum, but steel cans are still common in other markets. Steel is stronger but also heavier, and the dome geometry differs. The study on dome reversal used 0.18 mm-thick steel with a tensile strength of 466 MPa, which is substantially stronger than the typical aluminum alloy used in domestic beverage cans.³ Steel cans can tolerate higher pressure before dome reversal, all else being equal.
• Physical damage: Dents, scratches, and corrosion all reduce the pressure a can can safely hold. A dent changes the local stress distribution and can create a weak point that fails well below the can’s rated capacity.
• Shaking: A can that has been jostled around in a hot car has more CO₂ released from solution into the headspace at any given moment, which raises effective pressure. Shaking alone does not permanently increase the equilibrium pressure, but it speeds up the release of dissolved gas and can tip a can that was right on the edge.

Cans of sparkling water, energy drinks, and beer are all subject to the same physics, though their carbonation levels and headspace volumes differ. Beer tends to be less carbonated than cola and may tolerate slightly higher temperatures before failure. Energy drinks vary widely. Sparkling water is often carbonated to levels similar to soda and behaves comparably.

Keeping Cans Intact in Hot Weather

If you are transporting soda in your car during summer, a cooler with ice or cold packs is the most reliable safeguard. Even a basic foam cooler in the trunk will keep cans well below the danger zone for several hours. Without a cooler, keeping cans on the floor of the passenger compartment (the coolest part of the cabin, since hot air rises) and out of direct sunlight helps, but only delays the inevitable on a truly hot day.

The worst place to leave cans is on the dashboard, the rear window shelf, or any surface that receives direct sunlight through glass. Those spots can reach temperatures 20 to 30 degrees above the already-elevated cabin air temperature. A can sitting on a black dashboard in full Arizona sun might be at 160 °F or higher within an hour, well past the failure zone.

If you find a bloated can in your car, do not open it immediately. The pressure inside is significantly higher than normal, and opening the tab will produce a vigorous spray. Let the can cool in a shaded area or a refrigerator for at least an hour before attempting to open it. If the can is already cracked or leaking, there is not much to do except clean up and accept the loss.

Why Manufacturers Do Not Simply Make Cans Stronger

A reasonable question is why beverage companies do not just build cans thick enough to survive any plausible temperature. The answer is economics and weight. Aluminum is expensive, and beverage cans are produced in the hundreds of billions globally each year. Even a tiny increase in wall thickness adds up to enormous material costs and increases shipping weight. The current design is a careful optimization: strong enough to handle normal distribution, storage, and refrigeration with a comfortable safety margin, but not so overbuilt that it wastes metal.

The engineering behind modern cans is genuinely impressive. A standard 12-ounce aluminum can weighs about half an ounce and holds back roughly 50 to 60 psi of internal pressure, yet you can crush it easily by hand when it is empty because the thin walls only resist force effectively when pressurized from the inside. That internal pressure is what gives the can most of its structural rigidity. It is a design that works beautifully within its intended temperature range and fails predictably, rather than catastrophically, when pushed beyond it. Dome reversal acts as a kind of built-in pressure relief, in the sense that the dome pops outward before the can wall tears apart into shrapnel. You get a mess, but you rarely get injured by a soda can blowing up in your car. The failures are engineered to be annoying rather than dangerous.

At the hoop stress levels associated with 90 psi internal pressure, about 30,000 psi of stress lands on the can wall, which represents roughly 70 percent of the aluminum’s yield strength.¹ That is close to the material’s limit but still below the point where the sidewall itself would rip apart. The dome goes first, and the resulting leak or pop releases enough pressure to prevent a more violent sidewall fracture. In that sense, the concave dome is doing double duty as both a structural feature and a sort of safety valve, failing in the least dangerous way available.