I've never seen a thermos bottle with a relief valve. Not sure if all manufacturers in Europe have nonexistent QA or if it's just not a thing that's commonly needed since you can't heat the contents up in there anyway (it's not like an insulated water boiler, which does have a release valve). Never considered that someone might leave food in there long enough to build up explosive pressure. Feels a bit like saying a missing cat detector function in microwave ovens points at them having no quality control

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gcr 3 hours ago | parent [-]

I bet you’ve been using these your whole life without knowing it: in non-USA thermoses, the lid releases pressure before becoming mechanically free. You’d hear a “pop” and then the lid has to be twisted slightly further before it can be removed.

Not all safety features have to be obvious/obtrusive.

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Aachen 3 hours ago | parent [-]

I see no hole in the metal anywhere on the inside. The only non-metal part that touches the inside is a rubber(?) gasket/ring thingy that sits above the thread and is squeezed by the lid, which I take out to clean and there's only metal under there as well. How would this work? Did I get the exceptional model that doesn't have one and just didn't look at other models closely enough?

	▲	gcr 3 hours ago \| parent [-]
		Huh. I’d imagined the threading in the cap could be made this way