I made an espresso porter (well komodo dragon porter to be exact) I just added coffee ground for french press at the five minute mark left in the boil. I suppose you could add it in the secondary too. just make sure you get the coffee to a ripping boil for at least a minute or two. Im betting you would need on the higher end. I'd say two cups of espresso (i put in a whole cup of french press coffee)
~"A fine beer may be judged with only one sip, but it's better to be thoroughly sure.
On Deck: Spruce APA, Chambord Fortified Chocolate Porter, Imperial IPA
Secondary: Belgian Dark Strong Ale
Kegged/Drinking: Cascade, Cent., Amarillo Pale Ale
Kegged/Drinking: Belgian Pale Ale (HG yeast for yeast cropping see above)