[eellis327]

I'm a newer brewer and just brewed my first bourbon barrel porter.  I will be adding 16oz of bourbon later in the fermentation process(about two weeks into secondary).  Will this effect my gravity readings at all?

[kramerog]

Yes, but it will be pretty small if you are making a 5-gal batch b/c 1 part bourbon to 40 parts beer.  You could measure the gravity of your bourbon which would likely be below that of your beer I'm guessing b/c the gravity of alcohol is much less than water.

[Jimmy K]

Wait for fermentation to complete before adding the bourbon (should be done at 2 weeks anyway) then it won't matter. Take a gravity reading before adding bourbon. It will change final gravity, but you probably care more about abv. 16oz of 80 proof bourbon added to 5G of beer will raise the abv by 0.97%.
 
The calculation is.
 
abv of bourbon * volume of bourbon
 ------------------------------------ 
   (volume of beer + bourbon)
 
so
 
(40%abv * 16oz) / (640oz + 16oz) = 0.97%abv

[Jeff M]

Yes, but it will be pretty small if you are making a 5-gal batch b/c 1 part bourbon to 40 parts beer.  You could measure the gravity of your bourbon which would likely be below that of your beer I'm guessing b/c the gravity of alcohol is much less than water.

1 part bourbon at 40% to 40 parts beer at 5% isnt a small change per say;)  Follow the equation MTN put up.