Pork leg cuts: 3D, 4D, 5D and 6D explained

3D, 4D, 5D and 6D describe how far a pork leg has been broken down before it is packed: the higher the number, the more has been taken off — rind and fat, then bone, then separation into individual muscles. The scale is trade shorthand between European sellers and buyers, and nothing in EU law defines it. The one Union scale pig meat has — Annex IV, point B to Regulation (EU) No 1308/2013 — sorts whole carcases into classes S to P on estimated lean-meat content, and stops there. The Combined Nomenclature splits pig meat by carcase, bone-in against boneless and chilled against frozen; no line of it turns on a D number. A D number on its own is not a specification.

Where the convention comes from

The D scale is a commercial convention, not a published standard, and that is the whole of the problem. Compare a specification published in full: the United States Institutional Meat Purchase Specifications for fresh pork identify leg items one at a time — boneless, skinned with the pelvic bone removed, inside, outside, tip — and define their own trim vocabulary, so "denuded" means surface fat taken off down to the seamed surface. Nothing of that kind sits behind a D number. Two consequences follow.

First, it works. Within one supply relationship, or one national industry, the numbers are understood consistently enough to quote against and plan production around.

Second, it does not travel. Because nothing published fixes the definitions, the same number can mean different things across companies and borders. Two offers at the same D level can differ in rind, residual fat cover, whether the shank is on and whether the leg arrives whole or seamed — and those differences move yield and price.

The operations the scale tracks

What is not in dispute is the order in which a leg is worked. Which operations a supplier bundles under which number is contractual, not conventional.

Lower D numbers sit near the top of that list, higher numbers further down. Beyond that direction of travel, do not assume.

What the written specification has to carry

Because the number is only indicative, the contract has to do the work. A workable leg specification names, at minimum:

Photographs of accepted and rejected pieces, agreed before the first shipment, settle more disputes than wording.

Downstream uses

Cooked and injected ham

Whole-muscle cooked ham needs muscle integrity and predictable water-holding capacity. Legs for it sit at the higher-preparation end — boneless, defatted, seamed — so brine distributes evenly and the finished block slices without fat seams or connective tissue. pH is a real specification item here: muscle at the extremes of ultimate pH takes up and holds brine differently. Injection level and the resulting yield follow the destination market's labelling rules, not the cut description.

Dry-cured

Dry-curing runs the other way. Salt must migrate through an intact structure over months, and rind and fat cover protect the lean from over-drying and case hardening. Legs for dry-cure therefore sit at the low-preparation end: bone-in or minimally boned, rind on, controlled fat cover, tight weight range. Buyers add criteria the D scale cannot express — fat firmness, weight band, pH, sometimes breed and feeding. Where a protected designation of origin or geographical indication applies, Regulation (EU) 2024/1143 requires the product to comply with its registered specification, and no trade shorthand displaces that.

Further processing

Muscles outside the size or shape window for whole-muscle products, with the trim from every stage above, go to emulsions, sausage, diced and minced lines. There the D number stops mattering: the batch lean-to-fat ratio and its temperature and microbiological history take over.

What this means for your order

• Treat the D number as a filter for enquiries, not as the order. Ask each supplier for its definition of the level in writing, and compare definitions before prices.
• Price against the specification, not the label. Rind status and residual fat cover are where two apparently identical offers diverge.
• Check the customs classification separately. Additional note 2(A)(b) to Chapter 2 of the Combined Nomenclature defines a bone-in ham (leg) — subheadings 0203 12 11 chilled, 0203 22 11 frozen — as the rear part of the half-carcase including bones, with or without foot, shank, rind or subcutaneous fat. Derinding and trimming leave the code where it was; boning moves it. The D number has no customs meaning.
• Confirm destination-market requirements — certificate model, establishment approval, labelling language — independently of the commercial cut description.
• Write arrival checks as pass or fail, with the measurement method named: temperature, pH, fat thickness at stated points, and the trim defects that trigger rejection.