I did Randy Mosher's cold infusion from Radical Brewing, but I used a fine espresso grind (it was all I had) and it ended up being a thick sludge that was almost impossible to filter. I only ended up adding half of what I wanted to, but I also ended up getting some grounds in the coffee, which I think made it a bit bitter. However, after a few months it mellowed to a decent flavor. But I would maybe do a coarser grind if I did this again.