Pressure, and which containers hold it
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The container question that has no equivalent anywhere else in this estate: the package has to survive a reaction that continues after it leaves you.
A pressure vessel you are selling
A carbonated or live-fermented drink is a container under internal pressure, handled by the public, carried in bags, and left in warm cars.
When it fails it does not leak, it bursts, and glass under pressure fails violently.
That is the reason this page exists and the reason the container decision here is a safety decision rather than a cost one.
What generates the pressure
Carbonation you added, which is a known quantity you controlled.
Carbonation the product generated, from fermentation continuing in the bottle, which is not.
And temperature, which multiplies both. Carbon dioxide dissolved in a cold liquid comes out of solution as it warms, so the pressure in a bottle at 30 degrees is far above the pressure at 4.
A bottle filled cold, sealed, and left in a warm van is the standard failure scenario.
What each container takes
A pressure-rated glass bottle, the kind used for beer and soda, with a heavy base and a thick wall, designed and specified to hold internal pressure.
Ordinary glass: a juice bottle, a swing-top intended for still liquids, a decorative bottle, is not. It may hold for months and fail without warning.
PET, in a pressure-rated form, which is the carbonated soft drink standard. It deforms before it fails, which is a genuine safety advantage: a swollen PET bottle warns you.
Cans, which handle pressure well and need a seaming line.
The rule is simple and often broken: use a container specified for internal pressure, and ask the supplier for that specification rather than inferring it from the bottle looking sturdy.
Choosing for the worst case
Not the pressure at filling. The pressure after the remaining fermentable sugar has fermented, at the warmest temperature the product will realistically see.
Test it: bottles held warm for the full shelf life, behind a screen, and opened.
And build in margin, because the distribution chain will at some point be warmer than you planned for.