Passier, Stubben and Kieffer to my knowledge use vegetable tanned rather than chromium. I know for a fact that Passier is vegetable tanned. I’m pretty positive Kieffer is too, and Stubben, but would have to check.
First one must understand what tanning is - it’s basically, removing water molecules from collagen (the fibers in skin). Essentially, tannin molecules move through the leather (usually through soaking) and push out moisture/water. It’s much more complex than that but that’s the short and sweet. Leather undergoes tanning to produce longevity, elasticity, and pliability.
Chromium tanning (or mineral tanning) was the standard for a long time in leather goods - it’s probably what was used on the old Kieffer/Stubbens/Passiers. It’s very quick and convenient, easy to source, and much less expensive than vegetable tannins. It’s the same process – chromium tannins seep the leather, push out water/moisture, and produce a tanned leather hide. Leather tanned by chromium tanning is very soft and supple - it also makes the leather far more water resistant. It’s cheap, it’s obtainable, and it results in a hide that is supple even under duress, uniform in shade/surface area and available in a million and one colors and tones. The downside of having a million colors available is that the tanning process will typically strip the leather of its natural sheen, and you will not have an easy time darkening leather that was tanned by this process.
The drawback is that chromium cannot be recycled had has a significant negative impact on the environment because it is not biodegradable… and it gets dumped. India is a perfect example of that. The movement towards a more sustainable earth and the awareness of how negative chromium tanning is to the environment has caused some companies that are environmentally concerned/aware to shift towards vegetable tanning instead.
Vegetable tanning is tannins derived from plants – usually trees. Harvesting these tannins is incredibly time consuming and expensive, which is why so many companies shifted to chromium decades ago. Vegetable tanning creates a strong, sturdy hide - the base color can sometimes be inconsistent, and it is not as water or scuff resistant as chromium tanning products. The fibers in vegetable tanned leather are typically more visible, and it can be hard to shape/work with vegetable tanned leather – which is why it is usually used with craftsmen over produced en-masse. Vegetable tanning will make a leather that is more biodegradable, so extra care has to be taken to keep the leather soft and supple… but over time, the leather will get the rich patina that Horsemen All Long For. The trade-off is that vegetable tanning is very environmentally conscious.
Now… the reason why Leather Aint What It Used To Be – I think they’ve got the wool over your eyes – leather is better than ever… it just doesn’t come out with the same manufactured, silky feel that chromium tanned leather does. You have to earn your stripes (or your Patina) with these vegetable tanned leathers, but they last longer because they’re much sturdier and stretch less than their chromium counterparts.
A good example of a chromium tanned leather is Vespucci - and my god does that leather stretch… but it’s nice, soft, yummy leather. Some places say it is vegetable tanned but I really don’t think they’re right; Vespucci itself (WEB owned) mentions nothing about vegetable tanned. I think it was a buzzword used by Dover and other companies picked up on it. The Vespucci Veritas is the only Vespucci to my knowledge that is vegetable tanned.
Then there is hides…
A good hide is a good hide, no matter where it came from. Indian hides are actually much better than they used to be; India really has perfected the tanning industry (except for the wastage part) and I would not snub a leather that was Indian leather.
A good way to tell if it’s chromium vs vegetable tanned is to look closely at the cut edges of the leather. Chromium tanned leather HAS to be dyed as the chromium tanning process usually turns the leather a blueish to greyish color; manufacturers then will dye and paint it to get it the color they want. Vegetable tanned leather is usually flesh colored on the cut; it may be lighter or darker but will have no shade of blue.
Passier, last I checked, is German cowhide… but that doesn’t mean it does not get produced in India. I suspect that some of their strapgoods are. Stubben is German cowhide and made in Switzerland. Kieffer I am not up-to-date with.
In this day and age I don’t think where it is produced has as much to do with the quality as it used to.
Of the 3, I’d say Stubben is the best. Kieffer second. Passier is just ok.