I've only used a few refractometers, but they have all been accurate to a calibrated Hydrometer. Most hydrometers that I have owned were inaccurate before calibration.
Be aware that there has long been a problem with many, if not all, dual-scale refractometers that have both an SG and Brix scale. There has been an ongoing problem where they all seemed to have an incorrect SG scale. Hopefully that has been fixed, but it may be why they are on sale.
For example (I think)
10# of 2 row should be about 370 points
Divided by 5 gallons mash water should be 1.074 max.
80% would be about 1.060 or 15°
So if I hit 15° and stay there 15 min I figure it's converted.
Am I wrong or crazy? Not experienced enough to really know, it's just how I've been doing it.
The math is wrong, since you don't account for the volume added by the dissolved sugar from the converted grain, but the answer is close enough.
Max gravity for 10# of base malt in 5 gallons of mash water is probably just under 1.065. You can figure out your target gravity with a pretty simple formula (I'd change the 37 to a 36 if there is much specialty malt in there):
Max points per gallon from mash = (# of grain*37)/(mash volume in gallons+(0.075 gallons*# of grain))
Topic: Refractometer Sale (Read 14066 times)
