title_body: What coarseness of grind works best for cold brew?
upvoted_answer: Two guides do have specific (though differing!) recommendations on coarseness of grind for cold brew. 
  
  
  Blue Bottle recommends a grind a bit finer than paper-filtered drip coffee (they compare it to the same grind as for AeroPress); they're using an immersion setup with a wool filter. 
  Kicking Horse recommends a medium-coarse grind, nearly like that of French press; they are using a similar setup but claim that a finer grind extracts more bitter compounds. 
  
  
  Personally, I use the latter because I find the filtering goes more easily with a coarser grind; see also this question about making cold brew easier to filter.
  
  This question also discusses the grind. See also related questions with the tag cold-brew.