Originally Posted by RustyPitchfork
So measure with a refractometer when it's wort and the the hyrdometer when it's done fermenting?
Or convert using a brewing calculator. But hydrometer is most accurate, since it's closer to measuring what you actually want.
Fyi, water has an r.i. of 1.33, ethanol is 1.36, and sugar increases r.i of water, which is why alcohol makes it look like there's more sugar per the refractometer.