I recently did a chocolate banana Stout and added real banana in 2 places.
First I bought some banana chips, 4 lbs, from a heath food store (didnt want a bunch of preservatives) and ground them up in a food processor. Those were added to the mash. No clue what sugars were added there.
Next I added mashed up ripened bananas, apporx 3lbs, mixed with rum infused with vanilla beans to the secondary.
NOW, I do 10 gal batches and my secondaries are spilt up between 2 carboys. I kegged the first carboy after only 7 days in secondary, the babana slurry was still retaining some yellow color but I was excited to see how this worked. The first week of kegged beer was good with a solid aroma of banana and a good amount of chocolate. but as it aged the banana faded and the chocolate took over. My second carboy is scheduled to be kegged and filtered (banana parts everywhere) tonight. Im oping that the 21 day secondary with banana will promote longer banana aroma and flavor. Im still not sure if the dried banana in the mash did much but it sure didnt hurt. Will report tomorrow on the difference.
I thought of using hefe yeast but I really didn't want any clovey flavors in a stout.