Virtually all syrup hydrometers work with the Murphy Cup as long as they have a BRIX scale.
Also, virtually all “standard size” hydrometers will fit inside the Murphy Cup. You just want to make sure that the bulb of your hydrometer can float freely inside the cup without getting hung up on anything.
Canadian Hydrometers vs US Hydrometers
We have received extremely positive feedback from our fellow sugar makers in Canada who are using Canadian hydrometers rather than US hydrometers.
That being said, to be absolutely technical, US hydrometers and Canadian hydrometers a hair different. If you look on the paper scale inside your hydrometer, it will indicate in fine print the temperature at which that hydrometer was calibrated. You will find that US hydrometers have been calibrated at 60ºF and Canadian hydrometers have been calibrated at 68ºF. All this means is that the US hydrometer will float at the 66.9º mark when the syrup is 60ºF while the Canadian hydrometers will do so at 68ºF.
This difference in calibration shifts the scale’s placement inside the hydrometer ever so slightly. 0.16 BRIX to be exact. Since the Murphy Dial is optimized for hydrometers calibrated at 60ºF, that is what will provide the best results.
If you are using a hydrometer that is calibrated at 68ºF (Canadian), you can add 0.16 BRIX to the dial reading to determine the most precise target value. That being said, most sugar makers cannot discern such a small difference between the readings. Hence, most users consider the difference to be negligible.