Hi all. Apologies if this has been answered elsewhere, but if it was, I couldn’t find it.
During hydrolysis of sucrose, the angle of polarized light shone through a sample rotates (or “inverts”) from what it had been when the sample was still sucrose. Not sure what implications this has for an instrument that measures refractive index.
I see that Milwaukee, Hanna, and other manufacturers make designated meters specifically for measuring invert sugar content, which leads me to believe there’s something different here from measuring refraction through a disaccharide.
Reason I’m asking this is that I brewed a strong bitter yesterday and used a pound of #3 invert syrup. I used a refractometer to take my OG measurement and found that it was about five points lower than anticipated given my boil gravity and boil-off volume. However, when I backed the invert syrup out of my predicted OG calculation, the refractometer reading was spot on.
I know, I should have taken a hydrometer reading. Next time.
For the folks here who have used invert syrup, have you noticed any discrepancy in your refractometer and hydrometer readings?