Hah! That was fast LOL. I thought I would check the articles at the website,
braintan.com and the first one I read had this,
The history of Brain Tan
The New World provided a seemingly endless supply of deer. The trade in buckskins, tanned and raw, boomed. Common laborers valued its durability. By the 1750's it was the style among the wealthy of Europe to wear yellow buckskin breeches and gauntlets. It was hunting and riding wear, fashionable in the most elite circles. Customs records indicate that between 1755 and 1773; 2,601,152 lbs. of deerskins were shipped to England from Savannah, Georgia, just one of many ports. Many of these skins had already been brain and smoke tanned by the Creek and Cherokee.
Now there is much, much more to the article and this is just a snippet but Matt Richards explains it, the buckskin "market"very well.