O K people, I was at the United Distillers archive the other day and I copied a file from 1903 that was the grain bills for their products. I am still studying their contents but there is one thing that I would share with you now.
Tkae a look in your old liquor cabinets to see if you have any pre-prohibition Kentucky Tavern or Glenmore bourbons. If you do then you have a four grain bourbon. The bourbon mashbills (for 1903 through 1917) have corn, rye, barley and oats. Sometimes it is listed as oat malt and other times it is listed simply as oats. Any home brewers out there that can tell me if oat malt is more or less efficient than barley malt?
They also list rye malt for use in making rye whiskey, but even then they still use some barley malt. I have always heard that the reason for using barley malt is that it creates more of the enzymes needed than rye or corn malt thus giving a better yield per bushel.