Description

The Haut à Courroies came first. Hermès built it around 1900 to carry a saddle and riding tack, and the Birkin descends from it rather than the other way round. The proportions still show the original job: taller through the body than a Birkin of the same number, with shorter handles sitting close to the frame, which makes it a bag to carry rather than to wear. At 40 it is a weekend format and was designed as one.

Porosus sits at the top of the Hermès skin hierarchy, marked on the leather with a caret beside the blind stamp and chosen for scales that run small and tightly symmetrical. The Lisse finish comes from burnishing the hide by hand with an agate stone until the natural proteins take a gloss, so the shine sits within the surface rather than over it. Poussière translates as dust and behaves like one: a sandy beige carrying gray underneath, warmer than Étoupe and less yellow than Gold, which on a high-gloss exotic reads as a shifting neutral rather than a fixed one.

Collector’s Insight:
The HAC is the rarer half of the pair by a wide margin, and most of what the house does produce lands at 32 and 36. A 40 in Porosus needs hides large enough to run the panels unbroken, which is the hardest raw material in the category to source. Poussière has not appeared in recent palettes, and Hermès rests colors rather than formally retiring them, so its absence is a supply condition rather than a permanent one. on a vintage high-gloss skin points to storage rather than use, which matters more here than it would on matte, since gloss records handling.

Insight:
HACs reach a narrower audience than Birkins, generally collectors who want the original format or the travel scale, and they price below comparably sized Porosus Birkins because the function is more specialized. Within that lane a rested neutral has an advantage over a bright one: the buyer for a large exotic is usually assembling a collection rather than making a statement, and neutral exotics move more readily in that group.