title_body: Breville Smart Grinder Pro setting for cold drip
upvoted_answer: While I do not own a Smart Grinder Pro, most local places that make cold brew/drip use a medium-fine grind. This picture below can give you a good illustration on how coarse you want your bean. 
  
  
  It is really preference, however, I have found that too fine of a grind (like espresso) will usually muddy up a filter and make it harder to pass through due to the lack of pressure. I am sure there is a setting guide either that comes with the box or online that you can use for drip/cold drip. Just remember to keep it coarse enough so that it does not come out too "powdery".
  
  Image source: http://www.bruer.co/blogs/news/12222337-cold-bruer-experiments-with-grind-size
  
  Edit: My recommendation is to use the "Drip Grind" coarseness. That means, a grind that is not as powdered down as espresso; grinds should be no larger that ~1-1.5mm in diameter. Usually the finer a grind is, the more pressure is needed to account for the surface area created.