Did the same thing but infused a couple oz's of KY straight bourbon with the coconut and vanilla for three days before adding to the secondary. An awesome cool weather brew even if the coconut came through a little heavier than I'd planned. Enjoy!
Excited about the brew I made last night. Used the american porter refill plus 1 cup brown sugar and 1 oz of toasted coconut flakes (in a hop sack). Going to add 1 tablespoon of vanilla extract in one week. It's basically a makeshift version of the Nilla Porter recipe just adding some coconut flakes. I did this same recipe without the coconut a few months ago and the beer was very good -- if anything, it just lacked a little flavor. Hoping the coconut helps this out.
I saw it mentioned on a video I watched, so I started the practice, dipping a Q-tip, in 1 Step solution and swab it. Being that the sample was taken and then the LBK was immediately place in the refrigerator, I think it will be Ok.