5th yr. of cold brewing. Costco Colombian whole bean which I ratio double strength. Water, fresh ground beans in 1 qt. plastic pitcher. In refrig. let slosh around for 24 hrs. while driving, pour thru filter and you have concentrate for 1/2 gal. makings. 1/2 cold brew/ 1/2 water and heat. Cold brew is never bitter with acid like hot brew coffee. Concentrate keeps for days refrigerated. I do a batch every 3/4 days when traveling, not daily. Usually a 16 oz. dose heated by micro or burner and I'm good to go. FYI, I have quadruple strengthened the ratio and prepped a weeks worth of camping coffee at home.