For awhile now I've been aging pre-boiled oak cubes in white wine and red wine. Pre-boiled oak cubes are preferable to leech out some of the harsher aspects of the fresh wood. I've mostly used these cubes in saisons and wild beers. (I've also used a 3-gallon whiskey barrel for my Vesuvius Imperial Stout.) I've had moderate success with this method, and have decided that I'd like to expand my use of these cubes.
Inspired by beers that use more exotic barrels, I decided to pull some things out of our liquor cabinet and will eventually try some of the new oak variants in small batches of beer. First, I've restarted a bourbon jar. The bourbon cubes can be used in stouts, but I also plan to use them with some dark saisons, inspired by beers such as Tired Hands Guillemot Nebula and Prunus, as well as Stillwater Barrel-Aged Existent. Another option would be a wild quad with fruit, along the lines of Lost Abbey Cuvee de Tomme.
I also went with brandy, which will initially be used in a gallon of my whiskey barrel aged imperial stout. I'm interested in how the double barrel character will work out. Aside from that, I'm thinking it could also work well with a dark saison, or even with a portion of Citrine. This would fall along the lines of the cognac barrel-aged lambics that Cantillon has done, 50N4E and LH12.
After that, my choices are a little more obscure. I went with some oak cubes in Tanqueray gin. I think a blonde saison with lime peel could be a nice twist on the gin and tonic concept. I think the level of gin cubes would need to be lower than other beers, or could perhaps be split with some white wine soaked cubes. Upright in Portland has had success doing gin barrel saisons, e.g. Sole Composition Jaune Quatre. I think a key to this would also be to use a relatively mild saison strain at a lower temperature.
Finally, I'm aging some oak cubes in Jagermeister. This isn't traditional at all, and I'm not aware of any breweries using this, but I thought the anise/black licorice character could go well with a stout, or perhaps even with a dark saison or wild ale in small doses. Since I'm not sure what else I might do with the Jagermeister that's been sitting around since college, this seemed like it'd be worth doing a single gallon experiment with at some point.