Advisory

Does the bag have a one-way valve to let the gas out?

ALS-COFFEE-1.2-VALVE-001

This question is worth asking but is not reducible to a check a page can settle. It is published as guidance, not as a test.

Assertion

degassing_valve is_stated true

Applicability

applies when
the product is roasted coffee in a bag
signal
product text discusses packaging

Accepted evidence

  • product_description — an explicit statement that this product's packaging includes a one-way degassing valve, attached to the size actually being sold

Explicitly insufficient evidence

What does not count, and why. Published because the omission is where a check quietly becomes a claim.

  • "airtight", "resealable", "zip-lock", "tin tie"
    These are closures rather than valves, a valved bag with no zipper and a resealable bag with no valve are both common, and a tin tie is documented as not airtight.
  • a product photograph appearing to show a valve
    Image content is not read, is frequently a stock or lifestyle shot, and often shows a different size or an older bag design.
  • a valve claimed on the brand's packaging page but not on this product
    Valve presence commonly varies by size within one brand, so a site-level claim does not establish a fact about this offer.
  • "keeps coffee fresh" or "oxygen barrier"
    Outcome and film claims rather than the valve, and the two are different mechanisms.
  • "vacuum sealed"
    A vacuum pack and a valved pack are different and largely incompatible approaches.

Conflict rules

  • When a closure and a valve are both mentioned — then record them separately; conflating closure with valve is the specific confusion this entry exists to catch

Discrimination

Authored expectation: no prediction, confidence low. The numeric band this standard used to carry is not published at this grammar version.

Valve presence is rarely stated per product even where the bag has one, so the assertion would fail for most pages. It is published mainly so that the closure-versus-valve confusion is named, which is the part of this question a machine can genuinely check.

The numeric fail-rate band this reasoning was authored with is NOT carried at grammar 1.2 and is not reproduced here. Authored bands held 1 of 10 against this category's own sample and every miss was HIGH, so a direction derived from the band would inherit the error that condemned it (SCHEMA.md §9.3 step 3). The band survives in ALS-COFFEE v1.1 (standard_hash f8ec2780f60c38931913e5b6cd37506500c8462709209de7180ba6691d6137e7), which is byte-frozen and still served.

For a shopper

A one-way valve lets carbon dioxide out without letting oxygen in, and only works while the seal is intact. It tells you nothing about how old the coffee is, so it is not a substitute for a roast date.

For a merchant

If the pack for this size has a one-way valve, say so on the product page and keep it distinct from resealability, which is a different feature.

Grounding

  • Perfect Daily Grind (trade_press)
    the documented function of a one-way degassing valve and the precondition that defeats the claim, namely that the bag must be completely sealed for it to be effective — and separately that a tin tie is not airtight while a zipper creates a seal