The alchemy of homemade vanilla extract

I had no idea that vanilla extract could be made from soaking bean pods in vodka or brandy, or that commercial extract must be 35% alcohol. So, what does soaking it longer (say a year) do for the flavor?

Ah, I can see you’re someone who believes that anything worth doing is worth overdoing!  Actually, though, maximum flavor extraction takes place in about seven weeks, so soaking the beans for a year won’t produce stronger flavor.  Furthermore, if the beans aren’t fully submerged in the alcohol (i.e., exposed to air), they could mold and foul the entire batch.