Why vegetable-tanned leather outlives everything else

Almost all leather sold today — somewhere around ninety per cent of it — is chrome-tanned. Chromium salts, a rotating drum, and the hide is done in roughly a day. It comes out soft, uniform, cheap, and slightly blue before it is dyed.

It is a genuinely clever industrial process. It is also why most leather dog collars look tired in a year.

What the other process is

Vegetable tanning uses tannins drawn out of tree bark — oak, chestnut, mimosa. The hides move slowly through a series of pits over four to eight weeks, each one a little stronger than the last. It is the method that existed before chromium, and the reason it survived is not romance. It is that the leather behaves differently.

Chrome-tanned leather is a finished thing. It is as good on day one as it will ever be, and from there it gets worse.

Vegetable-tanned leather is unfinished on purpose. It arrives firm and pale, and it takes the shape of whatever it spends its life doing.

What that means on a dog

Three things happen over the first year.

• It softens where it bends. The collar takes the curve of that particular neck and stops trying to be a straight strap. Nothing you do makes this happen faster; it comes from being worn.
• It darkens. Light, oils from the coat, and the air do this. A chestnut tan collar at eighteen months is a deeper, warmer colour than the one you unwrapped, and it is not a flaw — it is the whole reason people pay for this leather.
• It develops a surface. Small scratches burnish out rather than staying white. The grain gets a low sheen you cannot fake with a finish.

Chrome-tanned leather does none of this. It cracks along the fold, and the coating on top eventually flakes and shows the raw split underneath.

Full-grain, top-grain, genuine leather

Worth knowing, because the words are used to hide things.

• Full-grain is the outer surface of the hide with nothing sanded off. It is the strongest part, with the tightest fibre structure, and it is what we use.
• Top-grain has had the surface sanded to remove scars, then a finish sprayed on. Smoother, weaker, and the finish is the bit that fails.
• “Genuine leather” is a legal term meaning it contains leather. It is usually the split — the fuzzy underside — with a printed grain pressed onto it. It is the cheapest thing that can legally be called leather.

If a listing does not say full-grain, it is not full-grain. Nobody who has it stays quiet about it.

Why hand saddle-stitch, while we are here

A sewing machine makes a lockstitch: one thread on top, one underneath, looped together. Cut one stitch and the seam can unzip from that point.

A hand saddle-stitch uses two needles on one thread, passing through the same hole from both sides. Every stitch is independently knotted. Cut one and the two either side hold. It is perhaps ten times slower to make and it is the reason two-hundred-year-old harness in museums still has its seams.

How to look after it

Less than people think.

• Water is fine. Wipe off what is on the surface and let it dry slowly at room temperature. Rain does not ruin leather.
• Heat is what kills it. A radiator, a hairdryer, a hot car dashboard — heat drives the oils out of the fibres and they do not come back. That is what cracking actually is.
• Salt water gets rinsed the same day. Salt crystallises inside the fibres and cuts them from within.
• Condition twice a year. A little wax balm, worked in with a cloth, left overnight. Twice a year is plenty; more than that and you soften it past the point of being useful.

Do that and the collar outlasts the dog. Which is a strange thing to aim for, and also exactly the point.