Would it be safe to....

[JohnQ]

Fill half the barrel with 20 gallons of Vienna IPA, flush with CO2, put the bung in and leave it for 4 weeks before adding IIPA?

JQ

[jeffsmith]

Is it a used barrel? I'd be worried about it possibly drying out (and subsequently leaking).

[JohnQ]

I'm not worried about leakage, it's been empty for a while but is sealed tight with the bung and has a whisky coating on the inside, with another whisky coating to be applied prior to the beer going in. Though, maybe I should be worried about drying, not sure...fakr? Tom?
It will be fully sealed and stored at 55F, as it is now.
I'm more concerned about possible oxidization, but think that a full CO2 Flush should fix that. Especially since the beer will already be CO2 rich before going in and will likely be slowly giving up the CO2 from solution.
JQ

[Richard]

Tom and Fakr are the only ones with relevant experience here.

[fakr]

We flushed the keg with CO2 after adding the first 15GAL.  We added 15GAL every 2 weeks, with a CO2 flush after each.

I kegged the remaining of my half of the barrel 2.5 months after the first 15GAL was added.  No issues with the beer other than the whisky flavor becomming stronger and stronger with each keg I pulled out.

We also weren't able to keep the keg at a constant temp as it was in my garage.  The garage hit temps of up to 30C at times, which I think probably affected the taste of the beer, but it's still pretty damn good.

I wouldn't worry about the barrel drying out or being infected.  they are completely saturated with 60%+ Whisky.

If I could do it again, I would have started in the fall, so the temp wouldn't have reached so high in the garage.  Probably would have even built a quick box around it with a small space heater to keep it up around 10C.

Tom and I discussed reusing the barrel (if we can find a solid method for cleaning and sterilizing it) to make a lambic...and let it age all winterspring...bottling or kegging in the late spring when the temp gets up there in the garage.

[JohnQ]

Just added half a bottle of Talisker to the barrel, swished it...soaked it up...another quarter bottle...swish, soaked it up...what the hell, the rest of a new bottle in there...
Going to add the Vienna IPA later tonight or first thing tomorrow.

JQ