The Problem -
Winter weather is no friend to leather, especially polluted rainwater. Microscopically, leather is made up of collagen fibers. During tanning, hides are soaked in chemicals to prevent its fibers and their bonds from decomposing. Natural fats and oils are tumbled with the hides to keep the protein bonds from drying out and to make the leather supple.
Protein bonds must be lubricated and kept supple, this is the key to long lasting leather. If the bonds dry out completely, they shrink, become brittle and break. Once broken, they are permanently weakened. Soaking leather in oil may make it supple again, but damaged fibers can’t be repaired or strength restored.
When your equipment gets drenched, the water forms temporary bonds with the lubricating oils. These vital oils float to the surface as the water evaporates. That’s why the leather feels stiffer.
The Solution -
Take action to get therapeutic oil back into that wet leather before its fibers completely dry. Remove dirt, sweat and mud from the wet leather with a damp rag. If the leather is really dirty or old conditioner has come to the surface, use a non-greasy, neutral pH leather cleaner to get the surface clean.
Wet leather needs to absorb conditioner deep within its fibers to replace oils flushed out by water. While the leather is still damp, apply a light coat of a penetrating, neutral pH leather conditioner. Capillary action will pull the conditioner down between the fibers. Thick or waxy conditioners tend to stay on or near the leather's surface, so look for conditioners with a neutral pH and avoid cleaners or conditioners with a harsh, alkaline pH. An alkaline pH, such as that of soaps, can damage and eventually weaken leather fibers.
An Ounce of Prevention -
Water can move dyes, leaving spots and splotches on leather once dry. Often, stripping and re-dying is the only recourse to restore even color or the depth of color.
Preventing the problem with a waterproofing product is much easier. Grease based dressings form a physical barrier that keeps mud and water away from leather's pores. However, they are sticky, attract dirt, and cannot be used on nappy leathers like suede.
Silicone sprays are non-greasy and can be used on both suede and smooth leather. However, they can make leather surfaces slippery and can affect the color of porous leathers, and can dry leather if overused.
Acrylic copolymer is the newest option for waterproofing. It forms a microscopic net too fine for water molecules to penetrate but porous enough to allow water vapor to pass through. It creates a unique, flexible coating that protects leather fibers from rain, maintains breathability, isn’t slippery, and acts to fix dyes in porous suede.
If you're caught out in the rain, don’t panic, look at it as an opportunity to stop putting off that leather conditioning and waterproofing you've meant to do but just haven't gotten around to yet and embrace the opportunity to care for your tack!