Leather Properties and Care
What Makes Leather Breathable?
Leather breathes because water vapor moves through its porous fiber network. See how finishes cut that 5 to 9 times and which leathers breathe best.
Leather is breathable because it is a porous network of fibers: water vapor can move into and through that network, while liquid water has a harder time. How much it breathes depends mostly on the surface. In one study, a polymer finish cut the water vapor permeability of the same leathers by 5 to 9 times.
This guide is part of our hub on leather properties and care.
What "breathable" means for leather
For leather, "breathing" is measured as water vapor, not air. Leather researchers test it in two ways:
- Water vapor permeability: how much vapor passes through the leather.
- Water vapor absorption: how much vapor the leather takes up and holds.
For shoe uppers, the aim is to keep liquid water out while letting vapor pass as freely as possible, or at least be absorbed. One study tested this to EN ISO 14268 and EN ISO 20344 and cites a combined water vapor coefficient of at least 15 mg/cm² as the requirement.
What makes leather more or less breathable
The pattern is simple: anything that seals the pores lowers breathability, and a thin or water-attracting layer lowers it less. That is also the trade-off behind is leather water-resistant?: treatments that keep water out can also hold vapor in.
| Factor | Effect on breathability | Fact |
|---|---|---|
| Unfinished, porous surface | High vapor permeability, low waterproofness | – |
| Acrylic/polyurethane finish | Permeability 5 to 9 times lower in one study | – |
| More water-attracting (hydrophilic) coating | Permeability only about 3 times lower in the same study | – |
| Any of these finishes | Did not change how much vapor the leather absorbs | – |
| "Open" waterproofing (repellent net around the fibers) | Vapor still enters the fiber network | – |
| "Closed" waterproofing (oils sealing the pores) | Lower permeability and absorption | – |
| Wax dressings | Can block surface porosity | – |
Which leathers breathe best?
Going by the finish study, the leathers with the least surface coating keep the most of leather's natural permeability:
- Aniline leather is dyed with soluble dyes only, without a topcoat or pigmented sealant.
- Semi-aniline leather adds a thin protective top coat.
- Suede and nubuck are open-pored leathers, which is why they need sprays that do not seal the surface.
Pigmented, heavily coated leathers sit at the other end. Leather with punched holes is a separate case, covered in what is perforated leather?.
Heavy oiling can also work against breathability, since sealed pores and wax both reduce it. For the wider debate on oiling, see what leather conditioner does.
Is "breathable leather" real leather?
Not always. Artificial leather can be porous and breathable or impermeable and waterproof, depending on how it is built. DuPont coined "poromeric" for porous synthetic leathers, starting with Corfam in 1963. Polyurethane faux leather is a fabric base with a plastic coating.
So "breathable" on a label does not prove a material is leather; check the material list, and see is leather a textile? for how leather and fabric-based materials differ.
Breathability in a leather jacket
The hide and its finish set the baseline, and the lining is a separate layer. Most Leather Collection men's leather jackets let you pick a regular lining, a printed lining or no lining.
FAQ
Which type of leather is the most breathable?
Leathers with little or no surface coating, such as aniline leather, since coatings cut vapor permeability.
Is breathable leather real leather?
It may or may not be. The word is also used for artificial leathers, which can be breathable or waterproof depending on construction.
HitKB Editorial Team
HitKB articles are researched from published sources, cited in the text, and reviewed before publication.