Asking for a Bottle Bomb?

Well I'm bottling my Chocolate Stout tomorrow and just realized I may be bringing a great deal of suffering onto myself. My plan was to transfer the entire batch to the bottling bucket, add bottling sugar and bottle the first 22-24 as is. These will be the Chocolate Stout. I then planned on adding 20oz or so of cold espresso from the espresso maker my friend has. I would then bottle the remaining beer as a Mocha Stout. That way, on St. Patrick's Day, my friends will have a choice between Chocolate and Mocha. I figured it would be a fun experiment to try.

However, while sitting on the couch reading some Hunter S. Thompson, it occured to me that adding espresso just before bottling might introduce a substantial amount of fermentables before sealing the Mocha Stout in bottles. Am I asking for Bottle Bombs? Is there any fermentable sugar in espresso? Does anyone know? I would just add it to my secondary fermentor a few days before bottle, but I don't want the who batch to be Mocha.
-Ben

I can't imagine that there is any material amount of sugar in espresso (I'd wager that there is none at all). Lots of people add coffee at bottling, I wouldn't worry about it in the least.

Espresso is a method of brewing coffee. Unless you add sugar, post-brewing, there are no fermentables.

I didn't know coffee was fermentable.
If it is I'm making me some coffee beer.

Just a minor point. You may want to add the priming sugar solution to the bottling bucket before the beer. That way, wehn you rack the beer, the sugar will get evenly mixed.

-a.

oh, well yes. A typo on my part.
-Ben