Originally Posted by Pith
Is that testing OG and then FG (which was what?) and calculating the final abv? Not familiar with "triple scale".
*** EDIT *** Didn't realize that Pith's question was over a year old.. hope he got that question resolved..
Triple Scale hydrometers are almost standard.. they have three different scales. One for specific gravity, one for balling/brix, and one for potential alcohol.
Typically, we only use the SG scale. The others can be used.. for instance, Brix can be used to get specific gravity.. but, there is math involved or you have to go to a converter. Potential alcohol.. can give you a ball park based on expected final gravity..
However the Specific Gravity scale is what is most useful. You take an Original Gravity reading of your wort.. hopefully very near the calibration temperature that the hydrometer is calibrated to.. usually 60* or 68*. There are brewing calculators that will help you out there. For instance, if your wort is at 70* and your hydrometer is calibrated to 60*, you'll need the converter to find out what the true OG is based on that different temperature.
The OG is not necessarily helpful initially.. but, you should write it down along with the date of the brew process and keep it with the ferment. If you bought a kit, you should be very close to the OG specified in the kit. Then at the end of, or what you think should be the end of the ferment, take another gravity reading. It should be at or near the final gravity listed in the kit. Take this at, say, 10 days into the ferment.. when bubbling has ceased.. or, say, one bubble every minute. Write this down on your brew day notes with the OG. Then take another gravity reading two days later. If the readings are the same, you are ready to bottle.
You can then use the OG and FG readings to calculate your alcohol percentage by volume which is the most common calculation. (%ABV) This can be done by going to a calculator.
There are come great calculators on the web.. I usually use Brewers Friend
as there are a number of calculators available including the hydrometer temp correction and the ABV calculators mentioned in my post.
Good luck and ask away for any other concerns.