Originally Posted by LilManBrewing
I have a recommendation for you. I've done an expresso stout in the past and here's what I did. I had the coffee beans ground to accommodate a French press. Boil the water, pour it over the beans then use the French press. Put the press in the fridge for 24 hours. Just pour in your carboy/conical when needed.
Depending on whether bitterness is of interest to you, you might also consider cold-brewing.How To Make Cold-Brew Coffee
Using hot water (boiled, I suppose) may give you a little coffee bitterness. I just finished up a chocolate coffee stout, and I used this cold-brew method instead of adding coffee to my boil as some do. I really like the result. It's not too bitter, and that coffee really hits you in the aftertaste. The method I linked above says you should dilute it to drink it, but... I just added the entire thing to the carboy. Remember to sanitize your French press before adding the coffee, etc. If you're still worried about sanitation, shake it up with some vodka before adding it in.
I'd mix up two or three batches of the above linked instructions (I think it's one cup by volume of coffee for that method), then add in each of them to taste. Sample it as you go.