For The Love Of Port

I have two new oak barrels that i'd like to eventually age Port in. On is small (2 Litre) and the other is larger (5 Litre). They are new oak (not neutral) so looking for suggestions on what to age in them for a while to make them more "neutral" before I fill them with Port.

Any ideas?

The smaller the barrel, the faster it can add influence. You’ll want to be thorough with the conditioning or those barrels will quickly do things you may not like. I’m not sure how they do this in the wine world, but folks doing this for whisky aging often use grain alcohol for the first fill.

For the 2 liter (and maybe the 5 if you are ambitious), you could age cocktails in them. Echoing what Mike said, these small barrels will give a lot of character quickly. I like the bamboo recipe that follows, and think I made a barrel aged negroni as well:
https://www.foodandwine.com/recipes/aged-bamboo

Buy a bunch of very cheap port from the market. Change it out every few months for about two years.