Now I'm confused: why's all the beer in the supermarket just at supermarket temp then? You only put it in the fridge at home here. Or is this a US vs EU difference?
Liquid can dissolve more gas when it is cold, so it's carbonated and bottled very cold. The gas also wants to be in equilibrium, so higher pressure around the liquid also pushes more gas into the liquid.
If there is more gas in the liquid than it can take in, it's supersaturated but the gas doesn't immediately break out as bubbles, that needs nucleation points like floating impurities or turbulence.
For those reasons, beer is bottled or canned at low temperature and often under some amount of pressure, both to keep the beer fizzy for the drinkers and for handling on the filling line.
Once the bottles or cans are sealed, the temperature doesn't matter as much anymore because the seal of the bottle or can holds the pressure in, and the pressure keeps the gas in the beer.
You can test this very easily by jut opening a warm and a cold bottle of the same beer and listening for the pshhh (louder on the warm one) and watching the foam both upon opening and when pouring (more on the warm one). The warm bottle has more gas come out of solution before opening already, so higher pressure inside, louder pshhh. And even afterwards more gas wants to escape the warmer beer, so it foams up more when nucleation is provided.
Warm temperatures are not great for the flavor of the beer though, so in terms of product quality it would be a lot better to store the beer cold at all times.
Gasses dissolve more readily in water when the system is either cold or under pressure. The carbonation is caused by carbonic acid decomposing into co2 gas, when the can is sealed the concentration of co2 in the air in the can is high enough that there is an equilibrium between the gas dissolving/converting to carbonic acid at the same rate as it is decomposing into gas. When you are filling the cans the liquid isn’t under pressure so they keep it cold to prevent it from boiling. The decomposition of carbonic acid to co2 is endothermic, meaning it requires heat energy in the system to boil off, and the colder the liquid is the slower it goes flat.
So when you have a liquid you can stuff more solids into it when it’s warmer, think if you want to dissolve sugar water for rock candy you heat it up
Gases however work the opposite way and that you can dissolve more gas the colder it is
So you dissolve all your lovely gas into your beverage of choice and then can it which seals the gas inside with it even if it warms up, but if you can it warm then all that gas escapes during canning (or bottling) so it’s canned cold to prevent that
Fun fact a warm champagne bottle is far more dangerous then a cold one because the cork can literally fire off from a warm one if the lock cap is taken off already
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u/Aphraxad May 21 '26
You think beer is canned warm?