How we compare gear
We have not brewed on any of this hardware. So instead of asking you to trust a test we did not run, here is a method you can check yourself.
Last updated September 1, 2026
The problem this page solves
Almost every site ranking kombucha gear claims hands-on testing. Some of them have done it. Many have not, and there is no way for a reader to tell which is which, because "we tested twenty jars" is unfalsifiable from the outside.
We take the other route. We say plainly that we have tested nothing, and we compensate by making everything else checkable: every figure is attributed, every score is computed from published weights, and the arithmetic is on this page. You do not have to take our word for a single ranking on this site.
Where the specifications come from
Every figure on a product comes from the maker's or the retailer's own published specification, retrieved on a stated date. That source line renders on the product itself, not buried in a footnote, so the provenance travels with the number.
The rules we hold to when compiling them:
- Verbatim where it matters. A pressure rating, a steel grade or a material claim is quoted in the maker's own words rather than paraphrased into something slightly different.
- "Not published" is an answer. Where a maker publishes no figure, the field says so. Mouth diameter on brewing jars is the commonest gap on this whole site, and it is the measurement a continuous-brew buyer most needs. Guessing at it would be worse than the gap.
- No transfer between models. EZ Cap publishes 100 PSI for its 16 oz bottle and does not state a figure for the 32 oz in the same line. So the 16 oz carries the rating and the 32 oz says the rating is not published for that size. Same maker, same product family, different rows.
- No remembered numbers. If it is not in a document we can point at, it does not go on the page.
The rubric, and its weights
Five criteria, weighted. The weights are niche-specific on purpose: kombucha sits at roughly pH 2.5 to 3.5 for weeks at a time, which is a genuinely hostile environment for hardware, so materials carries the most weight here in a way it would not on a site about bookshelves. Documentation is second, because a maker who publishes nothing is asking you to buy on faith — and this site exists for people who would rather not.
| Criterion | Weight | What it measures |
|---|---|---|
| Materials | 28% | What it is made of, and whether that survives months in a pH-3 liquid. |
| Documentation | 22% | How much the maker publishes, and how checkable it is. |
| Capacity fit | 16% | How well the stated size matches a batch someone actually brews. |
| Cleaning | 18% | Whether it comes apart far enough to clean without a fight. |
| Value | 16% | What you get for the money against the alternatives on the same page. |
A worked example you can check
Take the Craft a Brew Kombucha Jar with Valve (1 Gallon), which scores 8.0 out of 10 on this site. Here is exactly where that number comes from.
| Criterion | Score | Weight | Contribution |
|---|---|---|---|
| Materials | 9 | 0.28 | 2.52 |
| Documentation | 9 | 0.22 | 1.98 |
| Capacity fit | 7 | 0.16 | 1.12 |
| Cleaning | 6 | 0.18 | 1.08 |
| Value | 8 | 0.16 | 1.28 |
| Total | 1.00 | 7.98 |
Rounded to one decimal, that is 8.0. Every score on this site is computed by the same function from the same five numbers; none is typed in by hand.
How the five scores are assigned
- Materials rewards a published, acid-appropriate material: 304 or better stainless, lead-free glass, certified lead-free ceramic, a named food-grade polymer. An unnamed metal or an unspecified plastic scores low regardless of how it looks.
- Documentation rewards the number of figures the maker publishes and how specific they are. The Anchor Hocking jar scores a 10 because every external dimension is published to the eighth of an inch; a jar with no dimensions at all scores a 5 even when it is a perfectly good jar.
- Capacity fit asks whether the stated size matches a batch a person actually brews, in the context of the page it appears on. One gallon scores well for batch brewing and poorly for continuous brew — the same vessel, a different question.
- Cleaning penalizes parts. A plain jar with nothing to disassemble scores highest; a spigot that is hand-wash only scores lowest. This carries real weight because the vessel nobody wants to take apart is the vessel that ends a hobby.
- Value is relative to the alternatives on the same page, never absolute, and it is the only criterion that moves when a competitor changes.
Disqualifiers
Some things keep a product off this site regardless of how it scores:
- A spigot or vessel whose material is neither published nor inferable from a maker document. That is the one specification kombucha genuinely cannot tolerate a guess on.
- Brass or an unlabeled metal anywhere in contact with the liquid. Kombucha Kamp is explicit that brass is safe with higher-pH beverages like beer and not with kombucha.
- Bottles marketed for a second fermentation with no closure capable of holding pressure.
- Anything requiring a health claim to justify buying it.
Prices
Prices come from a live data layer and nowhere else. Nothing in our page copy contains a dollar figure, because a number written into prose is a number that goes stale silently.
The layer has a hard freshness gate of 48 hours. Past that, prices disappear from the site rather than ageing on the page, and every buy button falls back to "check price on Amazon". The feed is not live yet on this site, so no price is displayed anywhere and every button reads "check price".
How money enters the process, and where it stops
We earn affiliate commission on purchases made through links here. That funds the site. It does not influence a ranking, and there is a structural reason it cannot: the score is computed from five numbers assigned against published specifications, and the commission rate is not one of them.
Where a cheaper retailer is genuinely better for the buyer, we say so even when it pays less. The full arrangement is on the affiliate disclosure page.