Read any spirit’s address.

Seven segments separated by periods. Worked example: Weller 12 Year.

Twelve fixed root spirits. Every approved bottle in the library lives under exactly one of them.

The sub-class refines a root by legal class, region, or species. Bourbon and rye are sub-classes of American Whiskey. Speyside is a sub-class of Scotch. Espadín and Tobalá are sub-classes of Mezcal & Agave. There are 80+ sub-classes seeded today; here’s a sampler from five popular roots.

One character. Reads through the lens of the root. The same digit means different things under different roots — 3 under American Whiskey is wheated; 3 under Tequila is Reposado; 3 under Scotch is a blended malt. Always pair this segment with the root.

Reading rule: a grain digit in isolation is meaningless. It’s always "root + grain" that resolves to a style.

Two letters. Standard ISO codes most of the time, with one big exception: the United Kingdom is split into its constituents so a single-malt Scotch and an English single malt don’t share a code. Ireland gets its own slot (IE) — it’s a separate country. The literal UK code is reserved for blends that span multiple constituents.

Two to seven characters, depending on what’s meaningful. US states use their two-letter postal codes (KY, TN, TX). Scotch regions use the established two-letter shorthand (Highland, Lowland, Speyside, Islay, Campbeltown, Islands). French Cognac crus get longer prefixes (COG-GC — Cognac, Grande Champagne).

The last two segments answer who made it and which line is it.

Together, segments 4–6 (country.region.local) form the distillery registry code — a globally unique 3-segment identifier for every distillery in the catalog. Two spirits at the same distillery share their first six segments and only diverge at the lineup.

A "Small Batch Bottled-in-Bond Cask Strength Single Barrel" bourbon and a regular release of the same line share one Dewey code. The release-specific attributes don’t fragment the path; they live on the bottle as boolean flags (and one free-text field for cask finish).

Three full codes, segment by segment.

Every Dewey code is also a link. Drop the full path after myliquorlibrary.com/code/ and the library resolves it directly to the bottle. So myliquorlibrary.com/code/0100.0110.3.US.KY.010.014 opens Weller 12. Useful for sharing a tasting find without hunting down the search slug.

Dewey decimal classification has organized library shelves for 150 years because it does one thing extraordinarily well: it puts similar things next to each other. Open the bourbon section and you find every bourbon. Open the wheated bourbon subsection and you find every wheated bourbon. Open the Buffalo Trace stretch and you find every Buffalo Trace wheated bourbon, in order.

We borrowed the idea on purpose. When you find a bottle you love, the codes nearby are by definition the closest neighbors on the shelf — same root, same sub-class, same grain style, same producer. That’s not a coincidence; that’s the entire point. Shelved by similarity, so your next pour is never far from your last.

The recommendation engine uses the same hierarchy underneath. Filter by root, by sub-class, by grain — every navigation move is a Dewey lookup, even when the UI hides the codes.