Compostable packaging: the certificate decides it, not the adjective.

Compostable is a specific, tested claim: the material breaks down into compost under defined conditions within a defined time, certified to a standard such as ASTM D6400 or EN 13432. Biodegradable is a vaguer term with no single standard behind it, which is why a bare “biodegradable” claim does not survive a procurement review. The same confusion extends to recycled content (PCR) and to PHA, each of which means something different and is backed by a different credential.

The discipline that wins here is the same one that runs through the whole ECS library: name the standard, name the body, require the certificate number. A claim that resolves to a number is auditable; a claim that leads with an adjective is asking you to trust the marketing. That single habit is what separates a defensible compostable buy from a greenwashing risk.

Compostability is conditional, and the certification has to match the disposal environment your operation has. A clamshell certified for industrial composting will not break down in a backyard bin, and if your region has no commercial composting access, even a perfectly certified item ends up in landfill. So the first question is always: do your customers or your waste hauler have access to industrial composting, home composting, or neither? Then match the certification to that answer.

One more rule is now law in much of the US: no intentionally added PFAS. PFAS was historically used for grease resistance in fiber items, so grease-resistant bagasse and coated-paper formats must be PFAS-free with a fluorine screening to prove it. Get the disposal match and the PFAS screening right, and the rest of the spec (format, temperature rating, food-contact) follows cleanly.