The process you described Sheena is called 'swishing a barrel' and the results was called 'swish'. The first 'swish' had a very high alcohol content and it fueled many parties! :) Subsequent swishes could be done but each was less potent.
These barrels eventually become hard to get. I'm not sure if it was due to pressure from the Liquor Commission or the Board of Health! :)
Mavia