We didn't ferment in one, but we secondaried a Belgian Dark Strong in a used Jack Daniels barrel. After about 4 months in the barrel, we pulled off all the beer into kegs. I have actually yet to taste a carbed sample - trying to be super patient. I am also planning on bottling mine off - but anyway.
What we did was just get the barrel and put about 20 gallons of boiling water in it. Made sure it didn't leak, then rolled the barrel around. That was about all we did in terms of "sanitation." I mean, we put a 14% beer in there anyway - so I would assume infection risks are very minimal.
That is cool, ours was from Four Roses by way of Iron Hill lancaster. We plan to put Denny Conn's Vanilla Imperial Porter with madagascar vanilla bourbon beans in after secondary. I contacted Founders about it and they mentioned that they like to put the beer in when it as clear as possible.
The WHALES have been using barrels for all kinds of projects over the years but it's always been for secondary aging. The only one that was sort of done as a primary was a Cherry lambic. We racked all the batches in after only 3 days fermenting with WLP001. It continued fermenting in the barrel and had a resurgence when adding the 90lbs of Cherry.
I've been wanting to try brewing a bourbon stout for awhile, but my only experience was a spoiled batch from I'm guessing not getting the oak chips we used perfectly sanitized. Anyone who's using wood, how are you sanitizing your chips/barrels? Does boiling oak chips make them lose flavor?
Also, has anyone seen/brewed with the Jack Daniels smoking chips (made from Jack Daniels barrels)? I've been using them on the grill and in the smoker for a couple of summers, and it occurs to me they would probably be a great substitue for bourbon barrel aging for smaller batches.
If you read Wild Brews, there is a chapter on barrel aging, which is really good. I think he says the main thing to watch out for with bourbon barrels is the level of char within the barrel imparting a super heavy flavor on the beer. Bourbon barrels tend to be basically blackened on the insides, whereas wine barrels are toasted to a much lower extent.