Extra carbonation in spicy beer

I bottled some beer using a few different things to spice them up a few weeks ago. I only did this to about 8 bottles or so. When I opened any of the spicy beers, it foams up like crazy, but the beer that I didn't add spice to from the same batch is fine.

It is not a problem with head retention, because when you pour it into the glass, the head dissipates as you would expect. It just seems that there is something about adding spice to your beer that increases the amount of CO2 that the beer can dissolve.

Anyone else have this happen to them or know why this could be?

Having particles of any sort in your beer provides nucleation sites where CO2 can come out of solution. I have the same issue with beers that I bottle hop.

True. I expected this for the bottles I put crushed pepper in, but this still occurs in bottles with nothing more than 1/2 a jalepeno or 1/4 a habanero. I thought with larger items like these, the extra carbonation would be less pronounced.