Some days ago I stumbled upon with this coffee jar: Friis coffee vault.
Are products like this, with an special valve, really useful to preserve the freshness of ground or whole bean coffee?
So there are a fair few, well, questionable claims on that page, and some downright contradictions:
One Year of Friis Freshness Valves included, to vent freshness damaging CO2 gases
CO2 gasses are not 'freshness damaging'. CO2 is, to all intents and purposes, inert in this context. The only gas you really care about when freshness is concerned is Oxygen.
Also, a well-designed valve shouldn't wear out. It's not like a filter that gets clogged over time, it's just a mechanism.
Air-tight with a valve? It's either air-tight, or it has a valve...
What this product is, is a well sealed and opaque container. It will likely perform no differently from any other well sealed and opaque container.