I've done some research but...
Back on 11/1/2004 Ken Weber from BT posted here: "At Buffalo Trace Distillery, we first toast our barrels and afterward char them to a #4 level (55 second burn). We have experimented with several different char levels (going as high as a number 7 char, which just about destroyed the structural integrity of the barrel) to find the level that works best for us. The #4 level (in our opinion) yielded the best bourbon. By toasting the barrels (this was kind of an afterthought), we found that we could enhance the flavor of the #4 char."
Here's what Brad Boswell of Independent Stave told the Owensboro Bourbon Society on May 16, 2012 as posted on their site: "The seasoning of the barrel is key in bringing out the key flavors that each bourbon is striving to attain. Brad mentioned that on average, seasoning usually takes 6-9 months. In addition, roasting the barrel before charring can produce different flavor profiles. When discussing the 4 char levels Brad mentioned that all distilleries use either a 3 or 4 char for the barrel but many will use a 1 or 2 char for the barrel heads. Some artisan distillers are using a 2 char for their barrels however."
So what is meant or how are barrels specifically toasted before charring and who does this? Did you know barrel heads may have different char levels and who does that? Brown-Forman cooperage, in a video, says they kiln dry after air drying for up to a year. Independent Stave...do they also kiln dry after air drying? Finally, when did air drying come back in vogue as it appears that in the 50s and 60s kiln drying possibly replaced any air drying which then allowed Maker's Mark to market their return to air drying.
What got me thinking about all this is specifically is the comparison between BT and DSP 16 made wheaters and what I notice is a greater (not overwhelming but to me is there slightly) bitter wood almost soot taste in the BT wheaters versus that pure cotton candy (Randy's description and I agree) of DSP 16. Is that toasting and #4 char at BT the difference or do they do something different for the wheaters. Anybody know the barrel specs for DSP 16 even at their end run?