Not sure about the whole "smaller barrel=less time" thing after aging two beers in 5 gallon Journeyman Silver Cross barrels. I went 8 weeks. I tasted every week for the first few weeks, then decided to let it ride a couple more after each subsequent taste, as it wasn't where I wanted it quite yet.
As of kegging today, the beers have an amazing soft oak, vanilla, and very nice whiskey flavor. I plan on aging these beers in the keg for quite awhile, so I knew I was letting them go long for that reason as well.
One was a 7.5% Doppelbock and the other the same abv Xmas Ale. Refilled the doppelbock barrel after rinsing with distilled water with an American Barleywine, which I won't taste for a month.
Bottom line: Very good, very heavy flavor now. But great character. After aging time in keg, it will be great, I think.
Question: Any idea what contribution, in terms of abv, a first use whiskey barrel would have on the beer?