Yes you can tincture fresh coriander (cilantro)... The ratio widely used for tincture is 1:5... Meaning; for every one ounce of herb, use five ounces of grain spirits (vodka or Everclear are preferred) 100 PROOF EQUALS 50% ALCOHOL. 80 proof equals 40% alcohol... Etc. Different herbs require different alcohol content because of the different constituents of each plant, however, the 80 or 100 proof vodka or Everclear are widely used and accepted by many if not all that make tinctures. So, the water in the fresh herbs versus no water in the dried herbs means you will use less water (more alcohol/higher proof) a 200 proof grain alcohol AKA 100% will be used here, when using fresh herbs, and more water AKA 100 or 80 proof (50 to 40% alcohol)... What's the filler after alcohol? Water usually if it's clear... So that's where you get your water from when using dried as opposed to little to no water when using fresh because all fresh plants have water in them. Hopefully that cleared this up...