How Leather Is Tanned and Graded
From raw hide to finished material: the tanning process that stabilizes leather, and the grading system that sorts it by quality afterward.
By Ambrogio Shoes Editorial, in consultation with Ambrogio's Spain-based shoemaking team
· Updated July 9, 2026
Tanning is the chemical process, using either natural tannins (vegetable tanning) or chromium salts (chrome tanning), that converts a raw, perishable animal hide into stable, usable leather. After tanning, hides are graded based on factors like the natural surface's condition, thickness, consistency, and the presence of scars or imperfections, with full-grain leather from the least blemished hides sitting at the top of the hierarchy and progressively more processed or corrected leather occupying lower grades.
Turning Raw Hide Into Usable Leather
Tanning is the essential chemical process that converts a raw, perishable animal hide into stable, durable leather. Without it, hide would simply decay over time; tanning fundamentally transforms its protein structure, using either natural tannins in vegetable tanning or chromium salts in the much faster chrome tanning process.
How Tanned Leather Gets Graded
Once tanned, hides are sorted and graded based on the natural surface's condition, thickness, consistency, and the presence of scars or other imperfections. Full-grain leather, retaining the hide's complete natural surface with minimal correction, sits at the top of this hierarchy, prized for both durability and authentic character.
Why Grading Matters to a Buyer
Understanding this hierarchy helps explain why otherwise similar-looking shoes can carry very different price points and quality claims. Since there's no single universal, independently audited grading certification, trusting a reputable maker's transparency about sourcing and grading remains an important part of buying quality leather footwear.
Frequently Asked Questions
Why does raw hide need to be tanned at all?
Untreated animal hide will decay and break down over time; tanning chemically stabilizes the material's protein structure, transforming it into the durable, long-lasting leather used in shoes and other goods.
Is grading standardized across the entire leather industry?
Grading criteria and terminology can vary somewhat between tanneries and regions, though the general hierarchy — full-grain at the top, more heavily processed or corrected leather lower down — is broadly consistent across the industry.
Does a higher grade always mean a better leather for every use?
Generally higher grades offer better durability and aging character, but the "best" grade for a specific use also depends on the intended purpose — a firm vegetable-tanned leather ideal for a sole wouldn't necessarily be the top choice for a soft, supple upper.
Can grading be verified by a buyer, or is it based on trust?
Reputable tanneries and shoemakers typically stand behind their sourcing and grading claims, but there's no single universal, independently audited certification system a typical buyer can check directly, making trust in the maker's reputation an important factor.
Sources & further reading:
Leather Dictionary — Tanning and Grading Overview: https://www.leather-dictionary.com/
