I once heard a person say that they do not keep their shoes in a shoe box because they need to breathe.
While storing your shoes in a shoe box is a personal preference (or not), it has nothing to do with your shoes being able to breathe (unless it was air tight).
So, do shoes actually breathe, and if so how does that work?
When a shoe gets hot and sweaty its tongue doesn’t hang out like a dog’s does, but there are a lot of similarities between the two.
When dogs are hot they pant and let their tongue hang out to allow the moisture to evaporate and cool them down. Shoes breathe by allowing moisture to pass through the leather cellular structure to the outside exposed surface where it can evaporate.
When moisture cannot pass through the leather to evaporate it remains trapped in the cellular structure where it begins to slowly rot the protein bonds in the leather, and eventually destroys the shoe.
Since it is inherent in the structure of leather to pass moisture out to be evaporated it is important to know what can impede this process, and therefore damage your shoe.
There are two and a half culprits involved in suffocating shoes:
- Too much oil
- Too much wax [not as impactful as the other two]
The protein bonds in leather need oil to keep lubricated and flexible. However, too much oil can clog the cellular structure, allowing little to no water to pass through. In the past heavy applications of Mink oil was used as a type of weatherproofing. Heavy and frequent conditioning with oils can and will damage a shoe or boot over time, if they are not cleaned with a leather cleaner (like saddle soap or other leather cleaners) periodically.
It is also beneficial to get a shoe slightly moist with water before applying conditioning oils. This gives some “breathing” room to the cellular structure once the water evaporates out of the oil/water mix in the shoe as it dries. Of course oils can be washed out of leather (like stepping in a puddle, or standing in the rain), which is why a shoe should be conditioned after anytime it has been wet.
Silicone is probably the worst culprit, because it is included in so many leather protection products (mostly weatherproofing). Silicone makes a very good water barrier which is why it is used to protect leather from water damage (from the outside in, NOT the inside out). Because of this moisture introduced into the leather from an unprotected source (perspiration from your foot on the inside of the shoe) cannot escape to the exposed outer surface of the shoe (covered in silicone).
Due to the molecular makeup of wax it will actually allow moisture to pass through it to some degree, unless it is simply too thick (20 coats of wax is not good for your shoe, and you can actually get a better shine with 10 coats, or even less). Wax also does not go into the cellular structure of leather the way that oil and silicone can.
So, please allow your shoes to breathe, but if they start panting, take a picture and send it to me.