Food storage

Airtight is a claim with a test

A container is airtight if a seal is compressed by a closing mechanism, not if a lid fits snugly. The check takes five seconds: fill it with water, close it, turn it upside down over the sink. Anything that leaks water will let air through, and air is what makes crackers soft and coffee flat.

The second thing worth knowing is that food-contact approval attaches to a material and a use, not to a brand. It means a specific plastic has been assessed for a specific kind of contact. That is a real thing, and it is narrower than the phrase usually implies when it appears in marketing.

Sizes here are stated in quarts where we have them, because volume is the number that matters for a container and inches are the number that matters for the shelf it stands on.