In preparing to bottle an English Barley Wine I brewed back at the first of the year, I decided to go back and check my refractometer’s FG reading against my hydrometer. Looking back at my notes, I saw that my refractometer gave an OG reading of 24* P or 1.101, and a FG reading of 12.2* P or 1.016. Today’s refractometer reading showed 12.2* P once again while the hydrometer read 1.018.
I felt pretty good about both of these readings being basically in the same ballpark, but got a little concerned when I ran the numbers through NB’s calculator (bottom of the page)
that estimates ABV & OG based on FG in Brix and SG. According to that calculator, the OG should have been 1.093 and not 1.101. This left me with two questions:
Which number should I believe, my refractometer’s reading or the calculator’s estimate? I do check regularly to make sure that the refractometer is properly calibrated, so I don’t think there were any issues related to poor maintenance.
Do refractometer OG readings become less reliable at higher gravities? The reason I ask is that I also had a suspicious refractometer reading a while back when measuring the OG of a Cabernet I was making. In that case, the refractometer gave a reading that was suspiciously low. In general, the calculator’s estimate has always agreed with my refractometer’s OG reading when brewing beers in the 1.048-1.060 range.
Any insight would be appreciated!