Where The Guidance Stops

Most canning advice online is an argument about who is right. Almost none of it is an argument about which text, and that is the question that decides nearly every one of those arguments.

There is no single book called "the USDA guidance". There is a fixed federal document, last revised in 2015. There is a live university website that maintains that document and is quietly ahead of it. There is a federal health agency writing to a different audience with different assumptions. There are land-grant Extension services publishing under their own names, sometimes newer than all three. And there are manufacturers, some of whom copy the federal tables exactly and some of whom publish numbers that have no federal counterpart at all.

All of those are current. None of them is a hoax. Several of them disagree with each other, in writing, today.

This is the part of the subject nobody else covers, and it is not because it is obscure. It is because it is uncomfortable. A page that says "follow the USDA guidelines" is easy to write. A page that says "here are two USDA-derived texts that give different instructions, here is the date on each, and here is how to tell which one you are looking at" is harder, and it is the only kind of page that actually helps once you have noticed the problem yourself.

The four pages here.

Which document is current, and how to tell is the front door. The printed guide and the live site that maintains it are not the same text, and the clearest proof is a single safety panel that exists in two non-identical versions [F-14.6]. That page ends with a method you can run on any canning page you find tomorrow.

The lid contradiction: preheat, or do not puts two documents side by side that nobody has bothered to compare. The guide assumes a preheated lid. The lid manufacturer stopped recommending preheating, and an Extension service says it may be harmful [F-14.2]. Both positions are held in public by serious people.

Is a Ball recipe USDA-tested? is a literacy page, not an attack. "Ball" is the word a lot of home canners use to mean "safe", and the honest answer is that manufacturer-validated and USDA-tested are two different categories with two different evidence standards — which named food scientists will say on the record [F-15.1]. The same page covers a manufacturer doing genuine public service, because both things are true.

Tested and prohibited, never tested at all, and tested then withdrawn is the page that names this site's own method. "Not recommended" means three completely different things depending on the item, and one food had a published process that was later pulled with no replacement [F-14.10].

A fifth page belongs to this argument and lives elsewhere. Steam canning: what changed, and when sits in the water bath hub because that is where somebody looking for it will be. It is the cleanest single case on the site: three live texts from two organisations, two of them contradicting each other, and the maintainer stating in plain words that the primary document is behind its own research.

What this hub is not. It is not a claim that the tested guidance is unreliable. The opposite. A body of guidance that visibly updates, publicly withdraws a process it can no longer defend, and tells you in writing that a revision is pending is behaving exactly as evidence-based guidance should behave. The alternative — a source that never changes and never admits a gap — is not more trustworthy. It is just quieter about it.

What it does mean is that "the USDA says" is not a citation, and a page that cannot tell you which document, which page and which date has not read either text carefully enough to be worth following.