I use my refractometer for runnings and pre boil but my hydrometer for checking the sample from the CFC before I add the yeast and also after two weeks of fermentation.
I only use pre boil
Sounds like kind of a pricey investment if this is the only time you use it.
I just finally picked one up, and have used it on a couple of brews now. I’m using both the refractometer and the hydrometer each step of the way, so as to develop a solid correlation curve, based on information and a spreadsheet created by Sean Terrill, and to study for my self the benefits and limitations of both instruments. Science!
