Mike Tommasi's comments on a chestnut aged Brunello prompted me to query my barrel broker for details on chestnut barrels. Here are his comments:
"Chestnut is usually coated with paraffin or something similar. We did an experiment with untreated barrels at Mondavi in the early '80s. The results combined the worst of unripe persimmons, peanut butter and bad wine....something very tannic that stuck to the roof of your mouth."
I don't think I'll be conducting my own experiments anytime soon.
Tom S