I got a refractometer for Christmas and was doing some reading to find out that gravity readings of fermented wort are nearly useless without conversion charts. Found this out the hard way after I was baffled my beer was still at 1.029 (refractometer reading) after nearly two weeks, so grab the hydrometer and found my gravity was much lower and finished right around where i should be at around 1.011.
Anyway, the question I'm trying to get at is: yes, the gravity reading is WAY off from what it should be with the refractometer, but can I take gravity readings with the refractometer to see if the gravity is stable? That is, if I read the same reading with the refractometer over 3 days is this a reliable measurement to know that its done fermenting?
Its much easier and less wasteful to draw a small (inaccurate) sample then to draw a bigger sample to get an accurate reading. I could always check the gravity when I get it out of the carboy to get a stable reading with the hydrometer for FG, right?