I had an oak cask and wanted to know what the care and feeding for one was like. It's a little different than staves since you're not aging the beer in the oak. Some of it might help.
I never got a consistent, concrete answer, but here are some of the discussions that folks sent to me:
From Mike at Northern Brewer in 1999:
Here is Acton and Duncan's procedure for breaking in an oak barrel, taken
from the book "Progressive Winemaking:"
1 - Fill the barrel with cold water and let stand for 24 - 48 hrs. This
saturates the wood with moisture, causing the staves to swell and makes the
barrel watertight.
2- Drain the barrel and refill it with a solution of hot water and washing
soda (sodium carbonate - we sell something called Barolkleen that's sodium
sesquicarbonate and is a very strong version of what Acton and Duncan talk
about). Leave it overnight.
3- Pour off the washing soda solution and rinse the cask briefly with two
changes of cold water to remove residual soda solution.
4- Fill the cask again with hot water and stand overnight. This extracts the
washing soda solution from the wood. Repeat this step two or three times, or
until the water running out of the cask is colorless or very pale brown.
Then rinse again with cold water. A & D say that at this point, the cask
should "look clean and smell sweet."
5- Now you can sterilize it. Make a dilute sulfite solution (Campden
tablets, sodium metabisulfate, or potassium metabisulfate plus water). Fill
the barrel about one fourth full, bung it up tightly, and roll it around.
Pour this out and rinse it with a few more changes of cold water.
Then, before you actually put any wine or beer in the barrel, condition it.
Since the cask is new, there are a lot of tannins left in the wood which
would make any beverage which had been stored in it taste quite harsh. They
need to be leached out with an acidified version of whatever kind of liquid
you'll be storing in the barrel. Take one or two bottles of cheap wine, or a
six pack or two of cheap beer, add a teaspoonful of citric acid, pour it
into the barrel, bung it up and roll it around. Pour this out (don't drink
it) and fill the cask up all the way with your own wine or beer.
After this point, it's extremely important to keep the cask full and not let
it dry out. As soon as you remove one batch, have another one ready to
siphon in immediately. If the barrel dries out, the staves will pull apart,
and then you'll have to go through this whole procedure again.
And this was from Kirk Annand at Siebel:
The use of oak casks without 'brewers pitch' is not and never has been very
common in brewing. When barrels were a standard way to deliver draught beer
to taverns they were always coated with a brewers pitch first. This was a
tar-like compound that was melted and then added to the barrel and rolled
around in the barrel to completely cover the wood. A lot of old breweries
burnt down because of fires when they were melting the pitch! The purpose
of this pitch was to seal the keg so that air would not get in and carbon
dioxide out of the beer but also to prevent the wood coming in contact with
the beer. Wood is not a good material to come in contact with beer since
because of it porous surface it is almost impossible to eliminate beer
spoiling organisms. The Michael Jackson 'Beer Hunter' video on Czech beers
shows them removing and adding pitch to the old fermenters and storage tanks
that used to be used at Pilsner Urquell.
Lambic brewers use casks but since their beers naturally ferment with yeast
and bacteria from the air the barrels are just another way to get some of
the fermentation going. Using a barrel to get an 'oaked' character to beer
is difficult to control. Wine usually has a higher alcohol content than
beer as well as a lower pH and higher acidity. Beer is a much more delicate
beverage and sanitation is more critical in breweries than it is in
wineries. Using the techniques that vintner's use to break in a barrel is
not really acceptable for beer. I know brewers who use old whisky barrels
to brew beer in but they often use them to get some of the whisky character
into their beers. These barrels are also charred inside and the remnants of
the highly alcoholic liquid inside reduces the chance of wayward bacteria
that could spoil their beer.
I know this has probably been of little help for your cask so maybe someone
else knows how to prepare the cask for what you want to do.
And from an email with Charlie Papazian:
regarding caring for barrels... the winemakers take the lead on
this one. Don't use bleach. Don't use iodophor. Do what winemakers do.
Use a sulphite solution.