Used wine barrels?

Has anyone tried brewing Kombucha in used oak wine barrels? I've seen new barrels being marketed towards brewing, but I was wondering if it would be a problem using used ones, with their residue of wine and sulfites. I've been doing single gallon batches, but I'm now looking to start a continuous brewing process.

Whether used or new, using wood as the brewing vessel sounds appealing to me (keeps it dark, could add nice favor), but could end up being higher maintenance than a 5 gallon glass jar. Anyone had experience brewing in wood barrels?

If you buy a used barrel, you will need to ask questions about its cleaning/sanitation record as that will be the biggest issue. You need to check out Happy Herbalist's site, as there are many continuous brew containers available, and she even has oak kegs in smaller volumes (1gal-5 gal), and I could not find any prices better than that. Plus, that site has a wealth of information on culture/fermentation **Am in no way affiliated, just sharing the info*

Hey thanks for responding! I ended up ordering a 5 gallon glass jar. Just arrived yesterday. Gearing up to start my first continuous brew...