Adding spices in secondary

I brewed an Imperial Pumpkin Ale a few weeks ago and racked it into secondary this past weekend on to some high quality vanilla extract.

While I intend to age this brew until mid/late October (haven't decided if I'll leave it in carboys or rack to corny kegs) I've read that extended aging for spiced beers can mute the spices.

If this is the case, would adding spices to the beer later in the aging process be able to bring back the spice character that is noticeable in it's younger state?

You're right on both counts: aging spiced beers will definitely cause the spices to mellow over time, and a later addition - after the beer has conditioned for a while - will avoid this issue.

The problem with a late addition, though, is that adding spices exposes your beer to oxygen. Doing so after an extended period of conditioning means that there are fewer yeast cells left in solution to consume the oxygen and prevent staling.

In my opinion, the best solution is to add enough spices later on. That takes some practice and experimentation, but it's really the best answer.

As for your beer, I wouldn't worry to much. Vanilla isn't a delicate flavor like apricot, so it shouldn't vanish. Instead, it should mellow into the other flavors, which is desirable.

Thanks for the feedback. Since I have kegs I was contemplating adding a small amount of spices to each keg and racking a third time into them on top of the spices. Figure i can purge withe co2 to prevent oxyidation and add the spices close to to the point I'm going to bottle.

I'll probably keep 5G kegged and bottle 5G so I suppose I could not keg 5G and instead rack to a bottling bucket on top of spices, priming sugar and new yeast and bottle condition that way. Thoughts?